WO2014122599A1

WO2014122599A1 - Drug selection for colorectal cancer therapy using receptor tyrosine kinase profiling

Info

Publication number: WO2014122599A1
Application number: PCT/IB2014/058818
Authority: WO
Inventors: Phillip Kim; Sharat Singh
Original assignee: Nestec S.A.
Priority date: 2013-02-05
Filing date: 2014-02-05
Publication date: 2014-08-14
Also published as: EP2954328A1

Abstract

The present invention provides methods for selecting a suitable anticancer drug therapy, and for identifying and predicting response, for the treatment of colorectal cancer. The present invention also provides methods for monitoring the status of colorectal cancer and monitoring how a patient with colorectal cancer is responding to anticancer drug therapy. The present invention further provides methods for the rational selection of therapy with one or more anticancer drugs tailored to target signal transduction pathway components with dysregulated expression and/or activation levels in patients with somatic mutations in an oncogene.

Description

DRUG SELECTION FOR COLORECTAL CANCER THERAPY USING RECEPTOR TYROSINE KINASE PROFILING

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Application No. 13/800,777, filed March 13, 2013, and U.S. Provisional Application No. 61/761,026, filed February 5, 2013. The disclosures of each of these applications are hereby incorporated by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION

[0002] The process of signal transduction in cells is responsible for a variety of biological functions including, but not limited to, cell division and death, metabolism, immune cell activation, neurotransmission, and sensory perception to name but a few. Accordingly, derangements in normal signal transduction in cells can lead to a number of disease states such as diabetes, heart disease, autoimmunity, and cancer.

[0003] One well characteri zed signal transduction pathway is the MAP kinase pathway, which is responsible for transducing the signal from epidermal growth factor (EGF) to the promotion of cell proliferation in cells. EGF binds to a transmembrane receptor-linked tyrosine kinase, the epidermal growth factor receptor (EGFR), which is activated by the binding of EGF. The binding of EGF to EGFR activates the tyrosine kinase activity of the cytoplasmic domain of the receptor. One consequence of this kinase activation is the autophosphorylation of EGFR on tyrosine residues. The phosphoryiated tyrosine residues on the activated EGFR provide a docking site for the binding of SH2 domain containing adaptor proteins such as GRB2. In its function as an adaptor, GRB2 further binds to a guanine nucleotide exchange factor, SOS, by way of an SH3 domain on GRB2. The formation of the complex of EGFR-GRB2-SOS leads to SOS activation to a guanine nucleotide exchange factor that promotes the removal of GDP from Ras. Upon removal of GDP, Ras binds GTP and becomes activated.

[0004] Following activation, Ras binds to and activates the protein kinase activity of RAF kinase, a serine/threonine-specific protein kinase. What follows is the activation of a protein kinase cascade that leads to cell proliferation. In outline, RAF kinase then phosphorylates and activates MEK, another serine/threonine kinase. Activated MEK phosphorylates and activates mitogen -activated protein kinase (MAPK). Among the targets for further phosphorylation by MAPK are 40S ribosomal protein S6 kinase (RSK). The phosphorylation of RSK by MAPK results in activation of RSK, which in turn phosphorylates ribosomal protein S6. Another known target of MAPK is the proto-oncogene, c-Myc, a gene important for cell proliferation, which is mutated in a variety of cancers. M APK also phosphorylates and activates another protein kinase, MNK, which in turn phosphorylates the transcription factor, CREB. Indirectly, MAPK also regulates the transcription of the Fos gene, which encodes yet another transcription factor involved in cell proliferation. By altering the levels and activities of such transcription factors, MAPK transduces the original extracellular signal from EGF into altered transcription of genes that are important for cell cycle progression. [0005] Given the central role that signal transduction pathways play in cell growth, it is not surprising that many cancers arise as a result of mutations and other alterations in signal transduction components that result in aberrant activation of cell proliferation pathways. For example, overexpression or hyperactivity of EGFR has been associated with a number of cancers, including glioblastoma multiforme, colon cancer, and lung cancer. This has prompted the development of anticancer therapeutics directed against EGFR, including gefitinib and erlotinib for lung cancer, and cetuximab for colon cancer.

[0006] Cetuximab is an example of a monoclonal antibody inhibitor, which binds to the extracellular ligand binding domain of EGFR, thus preventing the binding of iigands which activate the EGFR tyrosine kinase. In contrast, gefitinib and erlotinib are small molecules which inhibit the intracellularly-located EGFR tyrosine kinase. In the absence of kinase activity, EGFR is unable to undergo autophosphorylation at tyrosine residues, which is a prerequisite for binding of downstream adaptor proteins, such as GRB2. By halting the signaling cascade in cells that rely on this pathway for growth, tumor proliferation and migration is diminished. [0007] Additionally, other studies have shown that about 70% of human melanomas and a smaller fraction of other tumors have a point mutation (V599E) in the Raf gene which leads to persistent activation of the MAPK pathway (see, e.g. , Davies et ai. , Nature, 417:949-954 (2002)). Such results suggest that mutations in particular signal transduction pathways may be characteristic of particular types of tumors and that such specific, altered signal transduction pathways may be a promising target for chemotherapeutic intervention.

[0008] Given that different cancer treatments, particularly cancer chemotherapy, may- function either directly or indirectly by means of either blocking or activating cellular signal transduction pathways involved in cell proliferation or death, respectively, the expression and/or activation of a given signal transduction pathway in a particular form of cancer such as, for example, colorectal cancer may serve as a good indicator of the efficacy of various cancer treatments. Accordingly, in addition to fulfilling other needs, the present invention provides a method for evaluating the effectiveness of potential anticancer therapies for an individual patient with colorectal cancer. As such, the present invention provides methods for assisting a physician in selecting a suitable cancer therapy for the treatment of colorectal cancer at the right dose and at the right time for every patient.

BRIEF SUMMARY OF THE INVENTION

[0009] The present invention provides compositions and methods for detecting the status (e.g., expression and/or activation levels) of components of signal transduction pathways in tumor cells from a colorectal cancer. Information on the expression and/or activation states of components of signal transduction pathways (e.g., HER1, HER2, HER3, cMET, cKIT, IGF-1R, ΡΪ3Κ, AKT, ERK, SHC, and other pathway proteins) derived from practice of the present invention can be used for colorectal cancer diagnosis, prognosis, and in the design of cancer treatments for colorectal cancer.

[0010] In particular embodiments, the present invention provides methods for therapy selection by detecting, quantifying, and comparing the expression levels and/or activation levels of a plurality of dysregulated signal transduction molecules in colorectal tumor tissue in a specific, multiplex, high-throughput assay, such as a Collaborative Enzyme Enhanced Reactive Immunoassay (CEER). The present invention also provides methods for the selection of appropriate therapy (e.g., single drugs or combinations of drugs) to down- regulate or shut down a dysregulated signaling pathway implicated in colorectal cancer. In certain embodiments, the present invention comprises signal transduction pathway profiling in combination with detecting (e.g., genotyping for) the presence (or absence) of one or more somatic mutations (e.g., detecting the presence or absence of one, two, three, four, or more mutations resident within the KRAS, BRAF, and/or PIK3CA oncogenes) in tumor tissues or other samples obtained from colorectal cancer patients. Thus, the present invention can advantageously be used to facilitate the design of personalized therapies for patients with colorectal cancer. [0011] The Collaborative Enzyme Enhanced Reactive Immunoassay (CEER) technology is described in the following patent documents, which are each herein incorporated by reference in their entirety for all purposes: PCT Publication Nos. WO 2008/036802, WO 2009/012140, WO 2009/108637, WO 2010/132723, WO 201 1/008990, and WO 201 1/050069; and PCT Application No. PCT/US201 1/066624. [0012] The present invention is based, in part, upon the surprising discover}⁷ that signal transduction pathway profiling of colorectal cancer cells using a specific, multiplex, high- throughput assay such as CEER can advantageously provide critical information for selecting the most effective targeted agents (e.g., for single, combination, or sequential therapy) for the treatment of colorectal cancer. Example 1 provides an exemplary comprehensive profiling of colorectal cancer patients via multiplexed functional pathway signature and somatic mutation analysis. Example 2 provides an exemplary comprehensive molecular analysis of oncogenic mutation and signaling pathway profile markers in primary and metastatic colorectal cancers.

[0013] The present invention is also based, in part, upon the surprising discovery that higher levels of expression and/or activation of non-ErbB receptor tyrosine kinases (RTKs) such as cMET and/or IGFIR were observed in KRAS mutant colorectal cancer patients when compared to KRAS wild-type colorectal cancer patients. See, Example 4 below. In certain aspects, the present invention provides method s for the rational selection of a combination of targeted agents based upon a combination of signal transduction pathway profiling and somatic mutation analysis. In particular embodiments, the present invention enables the identification of KRAS mutant patients with both ErbB -driven and ErbB-independent RTK expression and/or activation who would benefit from combination therapy and the selection of appropriate therapies targeting ErbB RTKs (e.g., HER1, HER2, HERS, and/or HER4) and non-ErbB RTKs (e.g., cMET and/or IGFIR). [0014] In sum, the methods of the present invention provide accurate prediction, selection, and monitoring of patients w ith colorectal cancer most likely to benefit from targeted therapy by performing pathway profiling using multiplexed, antibody-based proximity assays, alone or in combination with somatic mutation analysis, and comparing the pathway profile and/or somatic mutation analysis to prognostic molecular profiles predictive of a patient's response to particular anticancer therapies.

[0015] Other objects, features, and advantages of the present invention will be apparent to one of skill in the art from the following detailed description and figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 shows the KRAS and BRAF mutations that were identified in tumor samples obtained from colorectal cancer patients as described in Example 1.

[0017] Figure 2 shows the expression and/or activation levels of components of signal transduction pathways including HER1, cMET, HER2, HERS, IGF-1R, cKIT, PI3K, AKT, ERK, and SHC in tumor samples obtained from colorectal cancer patients as described in Example 1.

[0018] Figure 3 shows that the expression levels of cMET and IGF1R were significantly higher in KRAS mutant CRC patients than in KRAS WT CRC patients. [0019] Figure 4 shows that the activation (i. e., phosphorylation) level of cMET was significantly higher in KRAS mutant CRC patients than in KRAS WT CRC patients.

DETAILED DESCRIPTION OF THE INVENTION

I. introduction

[0020] The present invention provides methods for detecting the status (e.g., expression and/or activation levels) of one or a plurality of components of signal transduction pathways in tumor cells derived from colorectal tumor tissue or circulating cells of a colorectal tumor with an assay such as a specific, multiplex, high-throughput proximity assay as described herein (e.g. , Collaborative Enzyme Enhanced Reactive Immunoassay (CEER)). In certain embodiments, the present invention comprises signal transduction pathway profiling in combination with genotyping for the presence or absence of one or more somatic mutations in genes such as KRAS, BRAF, and/or P1K3CA (e.g., at one, two, three, four, five, or more polymorphic sites such as a single nucleotide polymorphism (SNP) in one or more of these genes) in tumor tissues or other samples obtained from colorectal cancer patients. In some particular embodiments, the signal transduction pathway profiling of the invention comprises determining the expression level (e.g., total amount) of at least one or more of FIERI, HER2, HERS, cMET, cKIT, TGF-1R, and/or CK (i.e., cytokeratin) and/or determining the activation level (e.g., level of phosphorylation ("p") or complex formation) of at least one or more of HER1 (e.g., pHERl), HER2 (e.g.. pHER2), HERS (e.g., pHER3), cMET (e.g., pcMET), cKIT (e.g., pcKIT), IGF-1R (e.g.. pIGF-lR), PI3K (e.g.. PI3K complex), AKT (e.g., pAKT), ERK (e.g., pERK), and/or SHC (e.g., pSHC).

[0021] The present invention also provides methods for the rational selection of anticancer drug therapy tailored to target one or more specific signal transduction pathway components (e.g., non-ErbB receptor tyrosine kinases (RTKs) and/or ErbB RTKs) with higher levels of expression and/or activation detected in a cancer cell obtained from a patient with a somatic mutation in an oncogene. In certain embodiments, the methods of the present invention rely- on the detection or measurement of higher levels of expression and/or activation of non-Erb B RTKs such as cMET and/or IGF1R in KRAS mutant patients compared to KRAS wild-type patients. In particular embodiments, the present invention enables the identification of KRAS mutant patients with both ErbB-driven and ErbB-independent RT expression and/or activation who would benefit from combination therapy and the selection of appropriate therapies targeting ErfaB RTKs (e.g., HER1 , HER2, HER3, and/or HER4) and non-ErbB RTKs (e.g., cMET and/or IGF 1R). [0022] Accordingly, the present invention also provides methods for selecting appropriate therapies to downregulate one or more deregulated signal transduction pathways involved in colorectal cancer. Therefore, the present invention may be used to facilitate the design of personalized therapies based on the particular molecular signature provided by the collection of total and/or activated signal transduction proteins, alone or in combination with somatic mutation analysis, in a given patient's colorectal tumor.

II. Definitions

[0023] The term "cancer" is intended to include any member of a class of diseases characterized by the uncontrolled growth of aberrant cells. The term includes all known cancers and neoplastic conditions, whetlier characterized as malignant, benign, soft tissue, or solid, and cancers of all stages and grades including pre- and post-metastatic cancers.

Examples of different types of cancer include, but are not limited to, digestive and gastrointestinal cancers such as colorectal cancer, gastric cancer (e.g. , stomach cancer), gastrointestinal stromal tumors (GIST), gastrointestinal carcinoid tumors, colon cancer, rectal cancer, anal cancer, bile duct cancer, small intestine cancer, and esophageal cancer; breast cancer; lung cancer (e.g.. non-small cell lung cancer (NSCLC)); gallbladder cancer; liver cancer; pancreatic cancer; appendix cancer; prostate cancer, ovarian cancer; renal cancer (e.g., renal cell carcinoma); cancer of the central nervous system; skin cancer; lymphomas; gliomas; choriocarcinomas; head and neck cancers; osteogenic sarcomas; and blood cancers. As used herein, a '^"tumor" comprises one or more cancerous cells. [0024] The term "analyte" includes any molecule of interest, typically a macromolecule such as a polypeptide, whose presence, amount (expression level), activation state, and/or identity is determined.

[0025] Hie term '^'signal transduction molecule" or "signal transducer" includes proteins and other molecules that cany out the process by which a cell converts an extracellular signal or stimulus into a response, typically involving ordered sequences of biochemical reactions inside the cell. Examples of signal transduction molecules include, but are not limited to, receptor tyrosine kinases such as EGFR (e.g., EGFR HERl/ErbB l, HER2/Neu/ErbB2, HER3/ErbB3, HER4/ErbB4), VEGFRl /FLTl, VEGFR2/FLK 1 / DR, VEGFR3/FLT4, FLT3/FLK2, PDGFR . (e.g., PDGFRA, PDGFRB), c-KIT/SCFR, INSR (insulin receptor), TGF-IR, IGF-IIR, IRR (insulin receptor-related receptor), CSF-1R, FGFR 1 -4, HGFR 1-2, CCK4, TRK A-C, c-MET, RON, EPHA 1-8, EPHB 1-6, AXL, MER, TYR03, TIE 1-2, ΊΈΚ, RYK, DDR 1-2, RET, c-ROS, V-cadherin, LTK (leukocyte tyrosine kinase), ALK (anaplastic lymphoma kinase), ROR 1-2, MUSK, AATYK 1 -3, and RTK 106; truncated forms of receptor tyrosine kinases such as truncated HER2 receptors with missing amino- terminal extracellular domains (e.g., p95ErbB2 (p95m), pi 10, p95c, p95n, etc.), truncated cMET receptors with mi ssing amino-terminal extracellular domains, and truncated HER3 receptors with missing ammo-terminal extracellular domains; receptor tyrosine kinase dimers (e.g., p95HER2/HER3; p95HER2/HER2; truncated HER3 receptor with HER1, HER2, HER3, or HER4; HER2/HER2; HER3/HER3; HER2 HER3; HER1/HER2; HER1/HER3; HER2/HER4; HER3 ER4; etc.); non-receptor tyrosine kinases such as BCR-ABL, Src, Frk, Btk, Csk, Abl, Zap70, Fes/Fps, Fak, Jak, Ack, and LIMK; tyrosine kinase signaling cascade components such as AKT (e.g., AKTL AKT2, AKT3), MEK (MAP2K1), ERK2 (MAPK1), ERKl (MAPK3), PI3K (e.g., PIK3CA (pi 10), PIK3R1 (p85)), PDK1, PDK2, phosphatase and tensin homolog (PTE ), SGK3, 4E-BP1, P70S6K (e.g., p70 S6 kinase splice variant alpha I), protein tyrosine phosphatases (e.g., PTP1 B, PTPN13, BDP1, etc.), RAF, PLA2, MEKK, JNKK, JNK, p38, She (p66), Ras (e.g., K-Ras, N-Ras, H-Ras), Rho, Racl, Cdc42, PLC, PKC, p53, cyclin D i, STATi, STAT3, phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 3,4,5-trisphosphate (PIP3), mTOR, BAD, p21, p27, ROCK, IP3, TSP- 1 , NOS, GSK-3P, RSK 1-3, JNK, c-Jun, Rb, CREB, Ki67, and paxilim; nuclear hormone receptors such as estrogen receptor (ER), progesterone receptor (PR), androgen receptor, glucocorticoid receptor, mineralocorticoid receptor, vitamin A receptor, vitamin D receptor, retinoid receptor, thyroid hormone receptor, and orphan receptors; nuclear receptor coactivators and repressors such as amplified in breast cancer- 1 (AIB1) and nuclear receptor corepressor I (NCOR), respectively; and combinations thereof,

[0026] The term "activation state" refers to whether a particular signal transduction molecule is activated. Similarly, the term "activation level" refers to what extent a particular signal transduction molecule is activated. The activation state typically corresponds to the phosphorylation, ubiquitination, and/or complexation status of one or more signal transduction molecules. Non-limiting examples of activation states (listed in parentheses) include: HERl EGFR (EGFRvITI, phosphorylated (p-) EGFR, EGFR: She, ubiquitinated (u~) EGFR, p-EGFRvlll); ErbB2 (p-ErbB2, p95HER2 (truncated ErbB2), p-p95HER2,

ErbB2:Shc, ErbB2:PI3K, ErbB2:EGFR, ErbB2:ErbB3, ErbB2:ErbB4); ErbB3 (p-ErbB3, trancated ErbB3, ErbB3 :PI3K, p-ErbB3 :PI3K, ErbB3 : She); ErbB4 (p-ErbB4, ErbB4: Shc); c- MET (p-c-MET, truncated c-MET, c-Met:HGF complex); AKTl (p-AKTl); AKT2 (p- AKT2); AKT3 (p-AKT3); PTEN (p-PTEN): P70S6K (p-P70S6K); MEK (p-MEK); KRK I (p-ERK l); ERK2 (p-ERK2); PDK1 (p-PDKl); PDK2 (p-PDK2); SGK3 (p-SGK3); 4E-BP1 (p-4E-BPl ); PIK3R1 (p-PIK3Rl); c-KTT (p-c-KTT); ER (p-ER); IGF- 1 R (p-IGF- lR, IGF- 1RIRS, IRS:PI3K, p-IRS, IGF-1R:PI3K); INSR (p-INSR); FLT3 (p-FLT3); HGFR1 (p- HGFR1); HGFR2 (p-HGFR2); RET (p-RET); PDGFRA (p-PDGFRA); PDGFRB (p- PDGFRB); VEGFR1 (p-VEGFRl, VEGFREPLCy, VEGFRE Src); VEGFR2 (p-VEGFR2, VEGFR2:PLCy, VEGFR2:Src, VEGFR2 heparin sulphate, VEGFR2:VE-cadhenn);

VEGFR3 (P-VEGFR3); FGFR1 (p-FGFRl); FGFR2 (p-FGFR2); FGFR3 (p-FGFR3);

FGFR4 (P-FGFR4); TTEl (p-TTEl); I l l -.2 (p-TIE2); EPHA (p-EPHA); EPHB (p-EPHB); 08Κ-3β (p-GSK-3P); NFKB (p-NFKB), 1KB (p-IKB, p-P65 :IKB); BAD (p-BAD, BAD: 14- 3-3); mTOR (p-mTOR); Rsk- 1 (p-Rsk-1 ); Jnk (p-Jnk); P38 (p-P38); STAT1 (p-STATl ); STAT3 (p-STAT3); FAK (p-FAK); RB (p-RB); Ki67; p53 (p-p53); CREB (p-CREB); c-Jun (p-c-Jun); c-Src (p-c-Src); paxiliin (p-paxillin); GRB2 (p-GRB2), She (p-Shc), Ras (p-Ras), GAB ! (p-GAB l), SHP2 (p-SHP2), GRB2 (p-GRB2), CRKL (p-CRKL), PLCy (p-PLCy), PKC (e.g., p-PKC , ρ-ΡΚΟβ, p-PKC5), adducm (p-adducin), RB I (p-RB l), and PYK2 (p- PYK2),

[0027] Hie term '^"oncogene" includes a gene that has the potential to cause cancer. Non- limiting examples of oncogenes include growth factors or mitogens such as c-Sis; receptor tyrosine kinases such as EGFR, HER2, PDGFR, and VEGFR; cytoplasmic tyrosine kinases such as Abl and kinases in die Src-family, Syk-ZAP-70 family, and BT family of tyrosine kinases; cytoplasmic serine/threonine kinases and their regulatory subunits such as P1K3CA, PIK3R1 , and RAF (e.g.. RAF- 1 , A-RAF, B-RAF); regulatory GTPases such as RAS (e.g., KRAS); transcription factors such as MYC; and combinations thereof.

[0028] The term "KRAS mutation" includes any one or more mutations in the KRAS (which can also be referred to as KRAS2 or RASK2) gene. Examples of KRAS mutations include, but are not limited to, G 12S, G12D, G12A, G12V, G 12R, G12C, G 13D, and combinations thereof. [0029] The term "BRAF mutation" includes any one or more mutations in the BRAF (which can also be referred to as serine/threonine-protein kinase B-Raf or B-Raf) gene. Examples of BRAF mutations include, but are not limited to, V600E, R461I, I462S, G463E, G463V, G465A, G465E, G465V, G468A, G468E, N580S, E585K, D593V, F594L, G595R, L596V, T598I, V599D, V599E, V599K, V599R, K600E, A727V, and combinations thereof. [0030] The term "PIK3CA mutation" includes any one or more mutations in the PIK3CA (which can also be referred to as PI3K or p 1 10-alpha) gene. Examples of PIK3CA mutations include, but are not limited to, E545A, E545G, E545K, Q546E, Q546K, H1047R, H1047L, 3204insA, and combinations thereof. [0031] Hie term ''EGFR mutation" includes any one or more mutations in the EGFR (which can also be referred to as HER1 or ErbBl) gene. Examples of EGFR mutations include, but are not limited to, deletions in exon 19 such as L858R, G719S, G719S, G719C, L861Q and S768I, as well as insertions in exon 20 such as T790M, and combinations thereof.

[0032] As used herein, the term "dilution series" is intended to include a series of descending concentrations of a particular sample (e.g., cell lysate) or reagent (e.g., antibody). A dilution series is typically produced by a process of mixing a measured amount of a starting concentration of a sample or reagent with a diluent (e.g. , dilution buffer) to create a lower concentration of the sample or reagent, and repeating the process enough times to obtain the desired number of serial dilutions. The sample or reagent can be serially diluted at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 500, or 1000-fold to produce a dilution series comprising at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 1 7, 18, 19, 20, 25, 30, 35, 40, 45, or 50 descending concentrations of the sample or reagent. For example, a dilution series comprising a 2-fold serial dilution of a capture antibody reagent at a 1 mg/ml starting concentration can be produced by mixing an amount of the starting concentration of capture antibody with an equal amount of a dilution buffer to create a 0.5 mg/ml concentration of the capture antibody, and repeating the process to obtain capture antibody concentrations of 0.25 mg/ml, 0.125 mg/ml, 0.0625 mg/ml, 0.0325 mg/ml, etc.

[0033] The term '^'superior dynamic range" as used herein refers to the ability of an assay to detect a specific analyte in as few as one cell or in as many as thousands of cells. For example, the immunoassays described herein possess superior dynamic range because they advantageously detect a particular signal transduction molecule of interest in about 1-10,000 cells (e.g.. about 1, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, or 10,000 cells) using a dilution series of capture antibody concentrations.

[0034] The term '^"sample" as used herein includes any biological specimen obtained from a patient. Samples include, without limitation, whole blood, plasma, serum, red blood cells, white blood cells (e.g., peripheral blood mononuclear cells), ductal lavage fluid, ascites, pleural efflux, nipple aspirate, lymph (e.g., disseminated tumor cells of the lymph node), bone marrow aspirate, saliva, urine, stool (i. e., feces), sputum, bronchial lavage fluid, tears, fine needle aspirate (e.g., harvested by random periareolar fine needle aspiration), any other bodily fluid, a tissue sample (e.g., tumor tissue) such as a biopsy of a tumor (e.g., needle biopsy) or a lymph node (e.g., sentinel lymph node biopsy), a tissue sample (e.g., tumor tissue) such as a surgical resection of a tumor, and cellular extracts thereof. In some embodiments, the sample is whole blood or a fractional component thereof such as plasma, semm, or a cell pellet. In other embodiments, the sample is obtained by isolating circulating cells of a solid tumor from whole blood or a cellular fraction thereof using any technique known in the art. In yet other embodiments, the sample is a formalin fixed paraffin embedded (FFPE) tumor tissue sample, e.g., from a solid tumor such as colorectal cancer. In particular embodiments, the sample is a tumor lysate or extract prepared from frozen tissue obtained from a subject having colorectal cancer.

[0035] Hie term '"subject" or '"patient" or "individual" typically includes humans, but can also include other animals such as, e.g., other primates, rodents, canines, felines, equities, ovines, porcines, and the like. [0036] An "array" or "microarray" comprises a distinct set and/or dilution series of capture antibodies immobilized or restrained on a solid support such as, for example, glass (e.g., a glass slide), plastic, chips, pins, filters, beads (e.g., magnetic beads, polystyrene beads, etc.), paper, membrane (e.g., nylon, nitrocellulose, polyvinyiidene fluoride (PVDF), etc.), fiber bundles, or any other suitable substrate. The capture antibodies are generally immobilized or restrained on the solid support via covalent or noncovalent interactions (e.g., ionic bonds, hydrophobic interactions, hydrogen bonds, Van der Waals forces, dipole-dipole bonds). In certain instances, the capture antibodies comprise capture tags which interact with capture agents bound to the solid support. The arrays used in the assays described herein typically comprise a plurality of different capture antibodies and/or capture antibody concentrations that are coupled to the surface of a solid support in different known/addressable locations.

[0037] The term "capture antibody" is intended to include an immobilized antibody which is specific for (i.e., binds, is bound by, or forms a complex with) one or more analytes of interest in a sample such as a cellular extract. In particular embodiments, the capture antibody is restrained on a solid support in an array. Suitable capture antibodies for immobilizing any of a variety of signal transduction molecules on a solid support are available from Upstate (Temecula, CA), Biosource (Camanllo, CA), Cell Signaling

Technologies (Danvers, MA), R&D Systems (Minneapolis, MN), Lab Vision (Fremont, CA), Santa Cruz Biotechnology (Santa Cruz, CA), Sigma (St. Louis, MO), and BD Biosciences (San Jose, CA). [0038] The term "detection antibody" as used herein includes an antibody comprising a detectable label which is specific for (i. e., binds, is bound by, or forms a complex with) one or more analytes of interest in a sample. The term also encompasses an antibody which is specific for one or more analytes of interest, wherein the antibody can be bound by another species that comprises a detectable label . Examples of detectable labels include, but are not limited to, biotin/streptavidin labels, nucleic acid (e.g., oligonucleotide) labels, chemically reactive labels, fluorescent labels, enzyme labels, radioactive labels, and combinations thereof. Suitable detection antibodies for detecting the activation state and/or total amount of any of a variety of signal transduction molecules are available from Upstate (Temecula, CA), Biosource (Camarillo, CA), Cell Signaling Technologies (Danvers, MA), R&D Systems

(Minneapolis, MN), Lab Vision (Fremont, CA), Santa Cruz Biotechnology (Santa Cruz, CA), Sigma (St. Louis, MO), and BD Biosciences (San Jose, CA). As a non-limiting example, phospho-specific antibodies against various phosphorylated forms of signal transduction molecules such as EGFR, c-KIT, c-Src, FLK- 1, PDGFRA, PDGFRB, AKT, MAPK, PTEN, Raf, and MEK are available from Santa Cruz Biotechnology.

[0039] The term ^"'activation state-dependent antibody" includes a detection antibody which is specific for (i. e., binds, is bound by, or forms a complex with) a particular activation state of one or more analytes of interest in a sample. In preferred embodiments, the activation state-dependent antibody detects the phosphorylation, ubiquitination, and/or cornplexation state of one or more analytes such as one or more signal transduction molecules. In some embodiments, the phosphoiylation of members of the EGFR family of receptor tyrosine kinases and/or the formation of heterodimeric complexes between EGFR family members is detected using activation state -dependent antibodies. In particular embodiments, activation state-dependent antibodies are useful for detecting one or more sites of phosphoiylation in one or more of the following signal transduction molecules (phosphoiylation sites correspond to the position of the amino acid in the human protein sequence): EGFR/HERl/ErbB l (e.g. , tyrosine (Y) 1068); ErbB2/HER2 (e.g., YI248); ErbB3/HER3 (e.g., Y1289); ErbB4/HER4 (e.g., Y1284); c-Met (e.g., Y 1003, Y1230, Y1234, Y1235, and/or Yl 349); SGK3 (e.g., threonine (T) 256 and/or serme (S) 422); 4E-BP1 (e.g., T70); ERKl (e.g., T185, Y187, T202, and/or Y204); ERK2 (e.g., T185, YI 87, T202, and/or Y204); MEK (e.g. , S217 and/or S221); PIK3R1 (e.g., Y688); PDK1 (e.g., S2/41); P70S6K (e.g. , T229, T389, and/or S421); ΡΤΈΝ (e.g., S380); AKTi (e.g., S473 and/or T308); AKT2 (e.g., S474 and/or T309); AKT3 (e.g., S472 and/or T305); 08Κ-3β (e.g., S9); NFKB (e.g.. S536); 1KB (e.g.. S32); BAD (e.g., S I 12 and/or S 136); mTOR (e.g., S2448); Rsk- 1 (e.g., T357 and/or S363); Ink (e.g., T183 and/or Y 185); P38 {e.g., T180 and/or Y182); STAT3 (e.g., Y 705 and/or S727); FAK (e.g.. Y397, Y576, S722, Y861, and/or S910); RB (e.g., S249, T252, S612, and/or S780); RB I (e.g., S780); adducin (e.g., S662 and/or S724); PYK2 (e.g.. Y402 and/or Y881); PKCa (e.g., S657); PKCa β (e.g., T368 and/or T641): PRC o (e.g., T505); p53 (c. S392 and/or S20); CREB (e.g., S 133); c-Jun (e.g., S63); c-Src (e.g., Y416); and paxillm (e.g., Y31 and/or Y 1 18).

[0040] The term "activation state-independent antibody" includes a detection antibody which is specific for (i. e., binds, is bound by, or forms a complex with) one or more analytes of interest in a sample irrespective of their activation state. For example, the activation state- independent antibody can detect both phosphorylated and unphosphoryiated forms of one or more analytes such as one or more signal transduction molecules.

[0041] The term "incubating" is used synonymously with "contacting" and "exposing" and does not imply any specific time or temperature requirements unless otherwise indicated.

[0042] "Receptor tyrosine kinases" or "RTKs" include a family of fifty-six (56) proteins characterized by a transmembrane domain and a tyrosine kinase motif. RTKs function in cell signaling and transmit signals regulating growth, differentiation, adhesion, migration, and apoptosis. The mutational activation and/or overexpression of receptor tyrosine kinases transforms cells and often plays a crucial role in the development of cancers. RTKs have become targets of various molecularly targeted agents such as trastuzumab, cetuximab, gefitinib, erlotinib, sunitinib, imatinib, niiotmib, and the like. One we 11 -characterized signal transduction pathway is the MAP kinase pathway, which is responsible for transducing the signal from epidermal growth factor (EOF) to the promotion of cell proliferation in cells.

[0043] The term "gene" and variants thereof includes the segment of DNA involved in producing a polypeptide chain; it includes regions preceding and following the coding region, such as the promoter and 3 '-untranslated region, respectively, as well as intervening sequences (introns) between individual coding segments (exons).

[0044] The term "genotype" and variants thereof refers to the genetic composition of an organism, including, for example, whether a diploid organism is heterozygous or

homozygous for one or more variant alleles of interest. [0045] The term "poly morphism" and variants thereof refers to the occurrence of tw^fo or more genetically determined alternative sequences or alleles in a population. A

"polymorphic site" refers to the locus at which divergence occurs. Preferred polymorphic sites have at least two alleles, each occurring at a particular frequency in a population. A polymorphic locus may be as small as one base pair (e.g. , single nucleotide polymorphism or SNP). Polymorphic markers include restriction fragment length polymorphisms, variable number of tandem repeats (VNTR's), hypervariable regions, minisatellites, dinueleotide repeats, trinucleotide repeats, tetranucleotide repeats, simple sequence repeats, and insertion elements such as Alu. The first identified allele is arbitrarily designated as the reference allele, and other alleles are designated as alternative alleles, "variant alleles," or "variances." The allele occurring most frequently in a selected population can sometimes be referred to as the "wild-type" allele. Diploid organisms may be homozygous or heterozygous for the variant alleles. The variant allele may or may not produce an observable physical or biochemical characteristic ("phenotype") in an individual carrying the variant allele. For example, a variant allele may alter the enzymatic activity of a protein encoded by a gene of interest or in the alternative the variant allele may have no effect on the enzymatic activity of an encoded protein. [0046] The term "single nucleotide polymorphism (SNP)" and variants thereof refers to a change of a single nucleotide within a polynucleotide, including within an allele. This can include the replacement of one nucleotide by another, as well as deletion or insertion of a single nucleotide. Most typically, SNPs are biallelic markers, although tri- and tetra-allelic markers can also exist. By way of non-limiting example, a nucleic acid molecule comprising SNP A\C may include a C or A at the polymorphic position. For combinations of SNPs, the term "haplotype" is used, e.g., the genotype of the SNPs in a single DNA strand that are linked to one another. In some embodiments, the tenn "haplotype" can be used to describe a combination of SNP alleles, e.g. , the alleles of the SNPs found together on a single DNA molecule. In further embodiments, the SNPs in a haplotype can be in linkage disequilibrium with one another.

III. Description of the Embodiments

[0047] The present invention provides compositions and methods for detecting the status [e.g., expression and/or activation levels) of components of signal transduction pathways in tumor cells from a colorectal cancer. In certain embodiments, the present invention further comprises detecting (e.g., genotyping for) the presence (or absence) of one or more somatic mutations (e.g., single nucleotide polymorphisms (SNPs)) in tumor ceils from a colorectal cancer. In certai n aspects, the present invention also provides compositions and methods for selecting appropriate therapies to downregulate or shut down one or more deregulated signal transduction pathways. Thus, certain embodiments of the invention may be used to facilitate the design of personalized therapies based on the particular molecular signature provided by the collection of total and activated signal transduction proteins and/or somatic mutations in a given patient's tumor {e.g., colorectal cancer).

[0048] In particular aspects, the present invention provides molecular markers (biomarkers) that enable the determination or prediction of whether a colorectal cancer can respond or is likely to respond favorably to an anticancer drug. In specific embodiments, measuring the level of expression and/or activation of at least one or more of HERl, HER2, HER3, cMET, cKIT, IGF-IR, PI3K, AKT, ERK, and/or SHC is particularly useful for selecting a suitable anticancer drug and/or identifying or predicting a response thereto in cells such as colorectal cancer cells {e.g., isolated cancer cells from a colorectal tumor). In other embodiments, the methods of the invention further comprise genotyping for the presence or absence of one or more variant alleles (e.g., somatic mutations) in genes such as KRAS, BRAF, and/or PIK3CA (e.g., at one, two, three, four, five, or more polymorphic sites such as a SNP in one or more of these genes). In particular embodiments, the determination of the presence or absence of the variant allele in conjunction with the determination of the expression level and/or activation level of one or more analytes further aids or improves the selection of a suitable anticancer drag and/or the identification or prediction of a response thereto in cells such as colorectal cancer cells (e.g., isolated cancer cells from a colorectal tumor).

[0049] In one aspect, the present invention provides a method for selecting a suitable anticancer drug for the treatment of a colorectal cancer, the method comprising:

(a) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HERL HER2, HER3, cMET, cKIT, IGF- I R, PI3K, AKT, ERK, SHC, and combinations thereof in a cellular extract produced from an isolated cancer cell; and

(b) selecting a suitable anticancer drug for the treatment of the colorectal cancer based upon the expression level and/or activation level of the one or more analytes determined in step (a).

[0050] In another aspect, the present invention provides a method for identifying the response of a colorectal cancer to treatment with an anticancer drag, the method comprising:

(a) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HERl, HER2, HER3, cMET, cKIT, IGF- IR, PI3K, AKT, ERK, SHC, and combinations thereof in a cellular extract produced from an isolated cancer cell; and (b) identifying the response of the colorectal cancer to treatment with an anticancer drug based upon the expression level and/or activation level of the one or more analytes determined in step (a).

[0051] In yet another aspect, the present invention provides a method for predicting the response of a subject having a colorectal cancer to treatment with an anticancer drug, the method comprising:

(a) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HER 1, HER2, HER3, cMET, cKIT, IGF- 1R, PI3K, AKT, ERK, SHC, and combinations thereof in a cellular extract produced from, an isolated cancer cell; and

(b) predicting the response of the subject having the colorectal cancer to treatment with an anticancer drug based upon the expression level and/or activation level of the one or more analytes determined in step (a).

[0052] In some embodiments, the expression level and/or activation level of the one or more analytes is expressed as a relative fluorescence unit (RFU) value that corresponds to the signal intensity for a particular analyte of interest that is determined using, e.g., a proximity assay such as the Collaborative Enzyme Enhanced Reactive Immunoassay (CEER) described herein. In other embodiments, the expression level and/or activation level of the one or more analytes is expressed as "±", "+", "++", "+++", or "++++" that corresponds to increasing signal intensity for a particular analyte of interest that is determined using, e.g., a proximity- assay such as CEER. In some instances, an undetectable or minimally detectable level of expression or activation of a particular analyte of interest that is determined using, e.g., a proximity assay such as CEER, may be expressed as "-" or "±". In other instances, a low level of expression or activation of a particular analyte of interest that is determined using, e.g., a proximity assay such as CEER, may be expressed as "+". In yet other instances, a moderate level of expression or activation of a particular analyte of interest that is determined using, e.g., a proximity assay such as CEER, may be expressed as "++", In still yet other instances, a high level of expression or activation of a particular analyte of interest that is determined using, e.g., a proximity assay such as CEER, may be expressed as "+++". In further instances, a very high level of expression or activation of a particular analyte of interest thai is determined using, e.g., a proximity assay such as CEER, may be expressed as "++++".

[0053] In yet other embodiments, the expression level and/or activation level of the one or more analytes is quantitated by calibrating or normalizing the RFU value that is determined using, e.g., a proximity assay such as CEER, against a standard curve generated for the particular analyte of interest. In certain instances, a computed units (CU) value can be calculated based upon the standard curve. In other instances, the CU value can be expressed as "±", "+", "++", "+++", or "++++" in accordance with the description above for signal intensity. Example 3 provides a non-limiting example of data analysis for the quantitation of signal transduction pathway proteins in cells such as cancer cells.

[0054] In certain embodiments, the expression or activation level of a particular analyte of interest, when expressed as "±", "+", "++", "+++", or "++++", may correspond to a level of expression or activation that is at least about 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9,5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100-fold higher or lower (e.g., about 1.5-3, 2-3, 2-4, 2-5, 2-10, 2-20, 2-50, 3-5, 3-10, 3-20, 3-50, 4-5, 4-10, 4-20, 4-50, 5-10, 5-15, 5-20, or 5-50-fold higher or lower) than a reference expression level or activation level, e.g., when compared to a negative control such as an IgG control, when compared to a standard curve generated for the analyte of interest, when compared to a positive control such as a pan-CK control, when compared to an expression or activation level determined in the presence of a anticancer drug, and/or when compared to an expression or activation level determined in the absence of an anticancer drug. In some instances, the correlation is analyte-specific. As a non-limiting example, a "+" level of expression or activation determined using, e.g., a proximity assay such as CEER, may correspond to a 2-fold increase in expression or activation for one analyte and a 5-fold increase for another analyte when compared to a reference expression or activation level,

[0055] In some embodiments, the cancer cell is isolated from a subject having the colorectal cancer after administration of an anticancer drug to the subject. In other embodiments, the isolated cancer cell is contacted with an anticancer drug. In either of these embodiments, the suitable anticancer drag may be selected by comparing the expression level and/or activation level of the one or more analytes to a reference expression and/or acti vation profile of the one or more analytes generated in the absence of the anticancer drag. In some embodiments, the colorectal cancer has metastasized.

[0056] In certain embodiments, step (b) comprises applying the expression level and/or activation level of the one or more analytes determined in step (a) to select a suitable anticancer drag for the treatment of the colorectal cancer, to identify the response of the colorectal cancer to treatment with an anticancer drag, or to predict the response of a subject having the colorectal cancer to treatment with an anticancer drug. [0057] In some aspects, the methods of the invention further comprise genotyping nucleic acid obtained from the cancer cell to determine the presence or absence of a variant allele in an oncogene.

[0058] In particular embodiments, the methods of the present invention further comprise the following step:

(a') genotyping for the presence or absence of a variant allele {e.g., somatic mutation) at a polymorphic site in an oncogene such as KRAS, BRAF, PIK3CA, and/or EGFR {e.g.. one or more somatic mutations at one, two, three, four, five, or more polymorphic sites such as a single nucleotide polymorphism (SNP) in one or more of these genes) in a cellular extract produced from an isolated cancer cell {e.g.. an aliquot of the cellular extract used in step (a)).

[0059] In other words, the genotyping step (a') comprises analyzing the cellular extract to determine the presence or absence of a variant allele {e.g., SNP) in one or more oncogenes such as KRAS, BRAF, PIK3CA, and/or EGFR. In these aspects, step (b) of the methods of the present invention comprise selecting a suitable anticancer drag for the treatment of the colorectal cancer, identifying the response of the colorectal cancer to treatment with an anticancer drug, or predicting the response of a subject having the colorectal cancer to treatment with an anticancer drug based upon the expression level and/or activation level of the one or more analytes determined in step (a) in combination with the presence or absence of the one or more variant alleles {e.g., somatic mutations) at the one or more polymorphic sites in the one or more oncogenes genotyped in step (a').

[0060] The presence or absence of a variant allele {e.g., somatic mutation) in an oncogene of interest can be determined using an assay described in Section VI below. Assays that can be used to determine somatic mutation or variant allele status include, but are not limited to, electrophoretic analysis, restriction length polymorphism analysis, sequence analysis, hybridization analysis, PGR analysis, allele-specific hybridization, oligonucleotide ligation allele-specific elongation/iigation, allele-specific amplification, single-base extension, molecular inversion probe, invasive cleavage, selective termination, restriction length polymorphism, sequencing, single strand conformation polymorphism (SSCP), single strand chain polymorphism, mismatch-cleaving, denaturing gradient gel electrophoresis, and combinations thereof. These assays have been well-described and standard methods are known in the art. See, e.g., Ausubei et al., Current Protocols in Molecular Biology, John Wiley & Sons, Inc. New York ( 1984-2008), Chapter 7 and Supplement 47; Theophilus et l , "PCR Mutation Detection Protocols," Humana Press, (2002); Innis et al, PCR Protocols, San Diego, Academic Press, Inc. ( 1990): Maniatis, et al. , Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Lab., New York, (1982); Ausubel et al., Current Protocols in Genetics and Genomics, John Wiley & Sons, Inc. New York (1984-2008); and Ausubel et ah, Current Protocols in Human Genetics, John Wiley & Sons, Inc. New Y ork (1984-2008); all incorporated herein by reference in their entirety for all purposes. In particular embodiments, the presence or absence of one or more variant alleles (e.g., one or more somatic mutations) in one or more genes of interest (e.g., oncogenes such as KRAS, BRAF, P1K3CA, and/or EGFR) is determined using a genotyping assay as described in U.S. Provisional Application No. 61/525,137, filed August 18, 2011, and U.S. Provisional Application No. 61/588,151 , filed January 18, 2012, the disclosures of which are herein incorporated by reference in their entirety for all purposes.

[0061] In some embodiments, the methods of the present invention may be useful to aid or assist in the selection of a suitable anticancer drug for the treatment of a colorectal tumor, to identify the response of a coiorectal cancer to treatment with an anticancer drug, or to predict the response of a subject having a colorectal cancer to treatment with an anticancer drug. In other embodiments, the methods of the invention may be useful for improving the selection of a suitable anticancer drug for the treatment of a colorectal tumor, to identify the response of a colorectal cancer to treatment with an anticancer drug, or to predict the response of a subject having a colorectal cancer to treatment with an anticancer drug. [0062] In one particular embodiment, the present invention provides a method for selecting a suitable anticancer drug for the treatment of a colorectal cancer, the method comprising:

(a) isolating a cancer cell after administration of an anticancer drug, or prior to

incubation with an anticancer drug;

(b) lysing the isolated cell to produce a cellular extract;

(c) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HER 1, HER2, HER3, cMET, cKIT, IGF- 1R, PI3K, AKT, ERK, SHC, and combinations thereof in the cellular extract; and

(d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of the anticancer drug to determine whether the anticancer drug is suitable or unsuitable for the treatment of the colorectal cancer. [0063] In another particular embodiment, the present invention provides a method for selecting a suitable anticancer drug for the treatment of a colorectal cancer, the method comprising:

(a) contacting a cancer cell obtained from a sample of the colorectal cancer with an anticancer drug;

(b) lysing the isolated cell to produce a cellular extract;

(c) determining the expression level and/or acti vation level of one or more analytes selected from the group consisting of HER 1, HER2, HER3, cMET, cKIT, IGF- 1R, PI3K, AKT, ERK, SHC, and combinations thereof in the cellular extract; (d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of the anticancer drug; and (e) indicating that the anticancer drug is suitable for the treatment of the colorectal cancer when the expression level and/or activation level determined for the one or more analytes is changed (e.g., substantially decreased) compared to the reference expression and/or activation profile,

[0064] In one particular embodiment, the present invention provides a method for identifying the response of a colorectal cancer to treatment with an anticancer drug, the method comprising:

(a) isolating a cancer cell after administration of an anticancer drag, or prior to

incubation with an anticancer drug;

(b) lysing the isolated cell to produce a cellular extract;

(c) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HER1, HER2, HERS, cMET, cKIT, IGF- 1 R, PI3K, AKT, ERK, SHC, and combinations thereof in the cellular extract; and

(d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of the anticancer drug to identify whether the colorectal cancer is responsive or non-responsive to treatment with the anticancer drag.

[0065] In another particular embodiment, the present invention provides a method for identifying the response of a colorectal cancer to treatment with an anticancer drag, the method comprising: (a) contacting a cancer cell obtained from a sample of the colorectal cancer with an anticancer drug;

(b) lysing the isolated cell to produce a cellular extract;

(c) determining the expression level and/or activation level of one or more analytes selected from the group consisting of FIERI, HER2, HERS, cMET, cKIT, IGF-

1 R, PI3K, AKT, ERK, SHC, and combinations thereof in the cellular extract;

(d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of the anticancer drug; and (e) indicating that the colorectal cancer is responsive to treatment with the anticancer drag (e.g., the colorectal tumor has an increased likelihood or probability of response to treatment with the anticancer drug) when the expression level and/or activation level determined for the one or more analytes is changed (e.g., substantially decreased) compared to the reference expression and/or activation profile,

[0066] In one particular embodiment, the present invention provides a method for predicting the response of a subject having a colorectal cancer to treatment with an anticancer drug, the method comprising:

incubation with an anticancer drug;

(b) lysing the isolated cell to produce a cellular extract;

(c) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HERE HER2, HER3, cMET, cKIT, IGF- 1R, ΡΪ3Κ, AKT, ERK. SHC, and combinations thereof in the cellular extract; and (d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of the anticancer drag to predict the likelihood that the subject having the colorectal cancer will respond to treatment with the anticancer drag. [0067] In another particular embodiment, the present invention provides a method for predicting the response of a subject having a colorectal cancer to treatment with an anticancer drag, the method comprising:

(a) contacting a cancer cell obtained from a sample of the colorectal cancer with an anticancer drag; (b) lysing the isolated ceil to produce a cellular extract:

(c) determining the expression level and/or activation level of one or more analytes selected from the group consisting of HERL HER2, HERS, cMET, cKIT, IGF- 1R, ΡΪ3Κ, AKT, ERK, SHC, and combinations thereof in the cellular extract;

(d) comparing the expression level and/or activation level of the one or more analytes determined in step (c) to a reference expression and/or activation profile of the one or more analytes that is generated in the absence of tiie anticancer drag to predict the likelihood that the subject will respond to treatment with the anticancer drug; and

(e) indicating that the subject having the colorectal cancer will likely respond to

treatment with the anticancer drug (e.g., the subject having the colorectal cancer has an increased likelihood or probability of response to treatment with the anticancer drug) when the expression level and/or activation level determined for the one or more analytes is changed (e.g., substantially decreased) compared to the reference expression and/or activation profile.

58] In some aspects, the methods of the invention further comprise genotyping nucleic acid obtained from the cancer cell to determine the presence or absence of a variant allele in an oncogene.

[0069] In certain embodiments, the methods of the present invention further comprise the following step:

(c') genotyping for the presence or absence of a variant allele (e.g., somatic mutation) at a polymorphic site in an oncogene such as KRAS, BRAF, PIK3CA, and/or EGFR (e.g., one or more somatic mutations at one, two, three, four, five, or more polymorphic sites such as a single nucleotide polymorphism (SNP) in one or more of these genes) in a cellular extract produced from an isolated cancer cell (e.g., an aliquot of the cellular extract used in step (c)).

[0070] In other words, the genotyping step (c') comprises analyzing the cellular extract to determine the presence or absence of a variant allele (e.g., SNP) in one or more oncogenes such as KRAS, BRAF, PIK3CA, and/or EGFR, In these aspects, the comparison of step (d) is used in combination with the genotyping of step (c') to detennine whether the anticancer drag is suitable or unsuitable for the treatment of the colorectal cancer, to identify whether the colorectal cancer is responsive or non-responsive to treatment with the anticancer drag, or to predict the likelihood that the subject having the colorectal cancer will respond to treatment with the anticancer drug. [0071] In certain instances, the methods of the present invention may further comprise a step of providing the result of the comparison obtained in step (d) to a user (e.g., a clinician such as an oncologist or a general practitioner) in a readable format. In some instances, the method may further comprise sending or reporting the result of the comparison obtained in step (d) to a clinician, e.g., an oncologist or a general practitioner. In other instances, the method may further comprise recording or storing the result of the comparison obtained in step (d) in a computer database or other suitable machine or device for storing information, e.g., at a laboratory.

[0072] In some embodiments, the expression [e.g., total) level and/or activation [e.g., phosphorylation) level of the one or more analytes is con sidered to be "changed" in the presence of an anticancer drug when it is at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% more or less activated than in the absence of the anticancer drug. In other embodiments, the expression (e.g., total) level and/or activation (e.g., phosphoiylation) level of the one or more analytes is considered to be "substantially decreased" in the presence of an anticancer drug when it is at least about 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% less activated than in the absence of the anticancer drag. In further embodiments, the expression (e.g., total) level and/or activation (e.g., phosphoiylation) level of the one or more analytes is considered to be "substantially decreased" in the presence of an anticancer drug (1 ) when there is a change from high or strong expression and/or activation of the analyte without the anticancer drug to medium, weak, low, or very weak expression and/or activation of the analyte with the anticancer drug, or (2) when there is a change from medium expression and/or activation of the analyte without the anticancer drag to weak, low, or very weak expression and/or activation of the analyte with the anticancer drug. [0073] To preserve the in situ activation states, signal transduction proteins are typically extracted shortly after the cells are isolated, preferably within 96, 72, 48, 24, 6, or 1 hr, more preferably within 30, 15, or 5 minutes. The isolated cells may also be incubated with growth factors usually at nanomolar to micromolar concentrations for about 1-30 minutes to resuscitate or stimulate signal transducer activation (see, e.g., Irish et al, Cell, 118:217-228 (2004)). Stimulatory growth factors include epidermal growth factor (EGF), heregulin

(HRG), TGF-a, PIGF, angiopoietin (Ang), NRG1, PGF, TNF-a, VEGF, PDGF, IGF, FGF, HGF, cytokines, and the like. To evaluate potential anticancer therapies for an individual patient, the isolated cells can be incubated with one or more anticancer drags of varying doses prior to, during, and/or afte growth factor stimulation. Growth factor stimulation can be performed for a few minutes or hours (e.g., about 1-5 minutes to about 1-6 hours). After isolation, treatment with the anticancer drug, and/or growth factor stimulation, the cells are lysed to extract the signal transduction proteins using any technique known in the art.

Preferably, the cell lysis is initiated between about 1-360 minutes after growth factor stimulation, and more preferably at two different time intervals: (1) at about 1-5 minutes after growth factor stimulation; and (2) between about 30-180 minutes after growth factor stimulation. Alternatively, the lysate can be stored at -80°C until use.

[0074] In some embodiments, the anticancer drug comprises an agent that interferes with the fimction of one or more activated signal transduction pathway components in cancer cells. Non-limiting examples of such agents include those listed below in Table 1.

Table 1

"""(Microtubule De-stabilizers)

[0075] In certain embodiments, the anticancer drug comprises an anti-signaling agent (i. e., a cytostatic drug) such as a monoclonal antibody or a tyrosine kinase inhibitor; an antiproliferative agent; a chemotherapeutic agent (i.e., a cytotoxic drug); a hormonal therapeutic agent; a radiotherapeutic agent; a vaccine; and/or any other compound with the ability to reduce or abrogate the uncontrolled growth of aberrant cells such as cancerous cells. In some embodiments, the isolated cells are treated with one or more and -signaling agents, antiproliferative agents, and/or hormonal therapeutic agents in combination with at least one chemotherapeutic agent.

[0076] Examples of anti-signaling agents suitable for use in the present invention include, without limitation, monoclonal antibodies such as trastuzumab (Herceptin®), pertuzumab (2C4), alemtuzumab (Campalh ^' ).. bevacizumab (Avastm®), cetuximab (Erbitux^®), gemtuzumab (Mylotarg*), panitumumab (Vectibix™), rituximab (Rituxan*), and tositumomab (BEXXAR®); tyrosine kinase inhibitors such as gefitinib { iressa ). sunitinib (Sutent¹^), eriotimb (Tarceva®), lapatinib (GW-572016: Tykerb**), canertinib (CI 1033), semaximb (SU5 16), vatalanib (PTK787/ZK222584), sorafemb (BAY 43-9006; Nexavar®), imatinib mesylate (Gleevec®), leflunomide (SU101 ), vandetanib (ZACTIMA™; ZD6474), pelitinib, CP-654577, CP-724714, HKI-272, PKI- 166, AEE788, BMS-599626, HKI-357, BIBW 2992, ARRY-334543, JNJ-26483327, and JNJ-26483327; and combinations thereof. [0077] Exemplary anti-proliferative agents include mT^'QR inhibitors such as sirolimus (rapamycin), temsirolimus (CCI-779), everolimus (RAD001), BEZ235, and XL765; AKT inhibitors such as lL6 iydroxymethyl-chiro-inositoI-2"(R)-2-0-methyl~3-0-octadecyi-s^,«- glycerocarbonate, 9-methoxy -2-methylellipticinium acetate, 1 ,3 -dihydro- 1 -( 1 -((4-(6-phenyl- lH-imidazo[4,5-g]quinoxalin-7-yl)phenyl)methyl)-4-piperidinyl)-2H-benzimi

10-(4'-(N-diethylamino)but>'l)-2-chlorophenoxazine, 3-formylchromone thiosemicarbazone (Cu(ll)Cl₂ complex), API-2, a 15-mer peptide deri v ed from amino acids 10-24 of the proto- oncogene TCL1 (Hironiura et al. , J. Biol, Chem., 279:53407-53418 (2004), KP372-1, and the compounds described in Kozikowski et a!., J. Am. Chem. Soc, 125: 1144-1 145 (2003) and Kau (· .:;/'.. Cancer Cell, 4:463-476 (2003); PI3K inhibitors such as PX-866, wortmannin, LY 294002, quercetin, tetrodotoxin citrate, thioperamide maleate, GDC-0941 (957054-30-7), IC87114, PI-103, PIK93, BEZ235 (NVP-BEZ235), TGX-1 15, ZSTK474, (-)-deguelin, NU 7026, myricetin, tandutmib, GDC-0941 bismesylate, GSK690693, KU-55933, MK-2206, OSU-03012, perifosme, tricinbine, XL- 147, PIK75, TGX-221, NU 7441, PI 828, XL- 765, and WHI-P 154; MEK inhibitors such as PD98059, ARRY-162, RDEA119, U0126, GDC - 0973, PD ! 84161, AZD6244, AZD8330, PD0325901, and ARRY-142886; and combinations thereof.

[0078] Non-limiting examples of pan -HER inhibitors include PF-00299804, neratinib (HKI-272), AC480 (BMS-599626), BMS-690154, PF-02341066, HM781-36B, CI-1033, BIBW-2992, and combinations thereof.

[0079] Non-limiting examples of chemotherapeutic agents include platinum-based drugs {e.g., oxaliplatin, cisplatin, carboplatin, spiroplatin, iproplatin, satraplatin, etc. ), alkylating agents (e.g., cyclophosphamide, ifosfamide, chlorambucil, busulfan, melphalan, mechlorethamine, uramustine, thiotepa, nitrosoureas, etc.), anti-metabolites (e.g., 5- fluorouracil, azatliioprme, 6-mercaptopurine, methotrexate, leucovorin, capecitabme, cytarabine, floxuridine, fiudarabine, gemcitabine (Gemzar*), pemetrexed (ALIMTA^®), raltitrexed, etc.), plant alkaloids (e.g., vincristine, vinblastine, vinorelbine, vindesine, podophyllotoxin, paclitaxel (Taxol^¾), docetaxel i^'l^'axoies ^' ). etc.), topoisomerase inhibitors (e.g., irinotecan, topotecan, amsacrine, etoposide (VPI6), etoposide phosphate, teniposide, etc.), antitumor antibiotics (e.g., doxorubicin, adriamycin, daunorubicin, epirubicin, actinomycin, bleomycin, mitomycin, mitoxantrone, plicamycin, etc.), pharmaceutically acceptable salts thereof, stereoisomers thereof, derivatives thereof, analogs thereof, and combinations thereof. [0080] Examples of hormonal therapeutic agents include, without limitation, aromatase inhibitors (e.g., aminoglutethimide, anastrozole (Arimidex*), letrozole (Femara*), vorozole, exemestane (Aromasin*), 4-androstene-3,6, 17-trione (6-OXO), I,4,6-androstatrien-3, 17- dione (ATD), formestane (Lentaron*), etc.), selective estrogen receptor modulators (e.g., bazedoxifene, clomifene, fulvestrant, lasofoxifene, raloxifene, tamoxifen, toremifene, etc.), steroids (e.g., dexamethasone), finasteride, and gonadotropin -releasing hormone agonists (GnRH) such as gosereiin, pharmaceutically acceptable salts thereof, stereoisomers thereof, derivatives thereof, analogs thereof, and combinations thereof.

[0081] Non-limiting examples of cancer vaccines useful in the present invention include ANYARA from Active Biotech, DCVax-LB from Northwest Biotherapeutics, EP-2101 from IDM Pharma, GV i OOl from Pharmexa, IO-2055 from Idera Pharmaceuticals, INGN 225 from Inirogen Tlierapeutics and Stimuvax from Biomira Merck.

[0082] Examples of radiotherapeutic agents include, but are not limited to, radionuclides such as ⁴⁷Sc, ⁶⁴Cu, ⁶⁷Cu, ⁸⁹Sr, ⁸⁶Y, ⁸⁷Y, ^9CY, ¹⁰⁵Rh, ^{! 11}Ag, ^{i i !}In, ^117mSn, ⁱ⁴⁹Pm, ¹⁵³Sm, ¹⁶⁶Ho, ^" L , " Re, " ' Re, ^" 'At, and ^{" '}Bi, optionally conjugated to antibodies directed against tumor antigens.

[0083] Non-limiting examples of HER2 inhibitors include monoclonal antibodies such as trastuzumab (Herceptin*) and pertuzumab (2C4); small molecule tyrosine kinase inhibitors such as gefitinib (Iressa^®), erlotinib (Tarceva^®), pelitinib, CP-654577, CP-724714, canertinib (CI 1033), HKI-272, lapatinib (GW-572016; Tykerb^®), PK1-166, AEE788, BMS-599626,

HKI-357, BIBW 2992, ARRY-334543, JNJ-26483327, and JNJ-26483327; and combinations thereof.

[0084] Non-limiting examples of c-Met inhibitors include monoclonal antibodies such as AMG102 and MetMAb; small molecule inhibitors of c-Met such as ARQ 197, JNJ-38877605, PF-04217903, SGX523, GSK 1363089/XL880, XL184, MGCD265, and MK-2461 ; and combinations thereof.

[0085] In certain embodiments, a reference expression or activation level of the one or more anaiytes is obtained from a normal cell such as a non-cancerous cell from a healthy individual not having a cancer such as colorectal cancer. In certain other embodiments, a reference expression or activation level of the one or more anaiytes is obtained from a tumor cell such as a colorectal cancer cell from a patient with a cancer such as colorectal cancer. [0086] In some em bodiments, the reference expression or activation level of the one or more analyles is obtained from a cell (e.g., a tumor cell such as a colorectal cell obtained from a sample) that is not treated with the anticancer drug. In particular embodiments, the cell that is not treated with the anticancer drug is obtained from the same sample that the isolated cell (e.g.. a test cell to be interrogated) that is used to produce the cellular extract is obtained. In certain instances, the presence of a low er level of expression or activation of the one or more analytes compared to the reference expression or activation level indicates that the anticancer drag is suitable for the treatment of the colorectal cancer (e.g., the colorectal tumor has an increased likelihood of response to the anticancer drug). In certain instances, the presence of an identical, similar, or higher level of expression or activation of the one or more analytes compared to the reference expression or activation level indicates that the anticancer drug is unsuitable for the treatment of the colorectal cancer (e.g., the colorectal tumor has a decreased likelihood of response to the anticancer drug).

[0087] In alternative embodiments, the reference expression or activation level of the one or more analytes is obtained from a cell sensitive to the anticancer drug that is treated with the anticancer drag. In such embodiments, the presence of an identical, similar, or lower level of expression or activation of the one or more analytes compared to the reference expression or activation level indicates that the anticancer drug is suitable for the treatment of the colorectal cancer (e.g., the colorectal tumor has an increased likelihood of response to the anticancer drag). In certain other alternative embodiments, the reference expression or activation level of the one or more analytes is obtained from a cell resistant to the anticancer drug that is treated with the anticancer drug. In such embodiments, the presence of an identical, similar, or higher level of expression or activation of the one or more analytes compared to the reference expression or activation level indicates that the anticancer drag is unsuitable for the treatment of the colorectal cancer (e.g., the colorectal tumor has a decreased likelihood of response to the anticancer drug).

[0088] In certain embodiments, a higher level of expression or activation of the one or more analytes is considered to be present in a cell or cellular extract when the expression or activation level is at least about 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100-fold higher (e.g., about 1.5-3, 2-3, 2-4, 2-5, 2- 10, 2- 20, 2-50, 3-5, 3-10, 3-20, 3-50, 4-5, 4-10, 4-20, 4-50, 5-10, 5-15, 5-20, or 5-50-fold higher) than the reference expression or activation level of the corresponding anaiyte in a cell (e.g., a colorectal cancer cell obtained from a patient sample) not treated with the anticancer drag, in an anticancer drug-sensitive cell treated with the anticancer drug, or in an anticancer drag- resistant cell treated with the anticancer drug.

[0089] In other embodiments, a lower level of expression or activation of the one or more analytes is considered to be present in a cell or cellular extract when the expression or activation level is at least about 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100-fold lower (e.g., about 1.5-3, 2-3, 2-4, 2-5, 2-10, 2- 20, 2-50, 3-5, 3-10, 3-20, 3-50, 4-5, 4-10, 4-20, 4-50, 5-10, 5-15, 5-20, or 5-50-fold lower) than the reference expression or activation level of the corresponding anaiyte in a cell (e.g., a colorectal cancer cell obtained from a patient sample) not treated with the anticancer drug, in an anticancer drag-sensitive cell treated with the anticancer drug, or in an anticancer drug- resistant cell treated with the anticancer drug.

[0090] Non-limiting examples of signal transduction molecules and pathways that may be interrogated using the present invention include those shown in Table 2.

Table 2

[0091] Non-limiting examples of analvtes such as signal transduction molecules that can be interrogated for expression (e.g., total amount) levels and/or activation (e.g., phosphorylation) levels in a cellular extract include receptor tyrosine kinases, non-receptor tyrosine kinases, tyrosine kinase signaling cascade components, nuclear hormone receptors, nuclear receptor coactivators, nuclear receptor repressors, and combinations thereof.

[0092] In one embodiment, the methods of the present invention comprise determining the expression level (e.g.. total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of at least one or more of the following analvtes in a cellular extract: ( 1) HER 1 /EGFR/ErbB 1 ; (2) HER2/ErbB2; (3) p95HER2 (truncated HER2); (4) HER3/ErbB3 ; (5) c-Met; (6) IGF 1 ; (7) cKit; (8) PT3K (e.g., PIK3CA and/or PIK3R1); (9) She; (10) Akt; (11) p70S6K; (12) VEGFR {e.g., VEGFRl, VEGFR2, and/or VEGFR3) and/or PDGFR (e.g., PDGFRA and/or PDGFRB); and (13) Erk {e.g., Erkl (MAPK3) and/or Erk2 (MAPK1)).

[0093] In another embodiment, the present invention comprises determining the expression level {e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of one of the following pairs of two anaiytes in a cellular extract, wherein "1" = HER1, "2" = HER2, "3" = p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF1R, "7" = cKit, "8" = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11" = p70S6K, "12" = VEGFR (e.g., VEGFRl, 2, and/or 3) and/or PDGFR (e.g.. PDGFRA and/or B), and "13" = Erk: 1,2; 1,3; 1,4; 1,5; 1,6; 1,7; 1,8; 1,9; 1,10; 1,11; 1,12; 1,13; 2,3; 2,4; 2,5; 2,6; 2,7; 2,8; 2,9; 2,10; 2,11; 2,12; 2,13; 3,4; 3,5; 3,6; 3,7; 3,8; 3,9; 3,10; 3,11; 3,12; 3,13; 4,5; 4,6; 4,7; 4,8; 4,9; 4,10; 4,11; 4,12; 4,13; 5,6; 5,7; 5,8; 5,9; 5,10; 5,1 ; 5,12; 5,13; 6,7; 6,8; 6,9; 6,10; 6,11; 6,12; 6,13; 7,8; 7,9; 7,10; 7,11; 7,12; 7,13; 8,9; 8,10; 8,11; 8,12; 8,13; 9,10; 9,11; 9,12; 9,13; 10,11; 10,12; 10,13; 11,12; 11,13; and 12,13.

[0094] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of one of the following sets of three anaiytes in a cellular extract, wherein "I" =

FIERI, "2" = HER2, "3" = p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF1R, "7" = cKit,

"8" = PI3K (e.g., PIK3CA and/or PIK3RI), "9" = She, "10" = Akt, "11" = p70S6K, "12" =

VEGFR (e.g., VEGFRl, 2, and/or 3) and/or PDGFR (e.g. PDGFRA and/or B), and "13" = Erk: 1,2,3; 1,2,4; 1,2,5; 1,2,6; 1,2,7; 1,2,8; 1,2,9; 1,2,10; 1,2,11; 1,2,12; 1,2,13; 1,3,4; 1,3,5;

1,3,6; 1,3,7; 1,3,8; 1,3,9; 1,3,10; 1,3,11; 1,3,12; 1,3,13; 1,4,5; 1,4,6; 1,4,7; 1,4,8; 1,4,9;

1,4,10; 1,4,11; 1,4,12; 1,4,13; 1,5,6; 1,5,7; 1,5,8; 1,5,9; 1,5,10; 1,5,11; 1,5,12; 1,5,13; 1,6,7;

1,6,8; 1,6,9; 1,6,10; 1,6,11; 1,6,12; 1,6,13; 1,7,8; 1,7,9; 1,7,10; 1,7,11; 1,7,12; 1,7,13; 1,8,9;

1,8,10; 1,8,11; 1,8,12; 1,8,13; 1,9,10; 1,9,11; 1,9,12; 1,9,13; 1,10,11; 1,10,12; 1,10,13;

1,11,12; 1,11,13; 1,12,13, 2,3,4; 2,3,5; 2,3,6; 2,3,7; 2,3,8; 2,3,9; 2,3,10; 2,3,11; 2,3,12; 2,3,13;

2,4,5; 2,4,6; 2,4,7; 2,4,8; 2,4,9; 2,4,10; 2,4,11; 2,4,12; 2,4,13; 2,5,6; 2,5,7; 2,5,8; 2,5,9;

2,5,10; 2,5,11; 2,5,12; 2,5,13; 2,6,7; 2,6,8; 2,6,9; 2,6,10; 2,6,11 ; 2,6,12; 2,6,13; 2,7,8; 2,7,9;

2,7,10; 2,7,11; 2,7,12; 2,7,13; 2,8,9; 2,8,10; 2,8,11; 2,8,12; 2,8,13; 2,9,10; 2,9,11; 2,9,12;

2,9,13; 2,10,11; 2,10,12; 2,10,13; 2,11,12; 2,11,13; 2,12,13; 3,4,5; 3,4,6; 3,4,7; 3,4,8; 3,4,9; 3,4,10; 3,4,11; 3,4,12; 3,4,13; 3,5,6; 3,5,7; 3,5,8; 3,5,9; 3,5,10; 3,5,11; 3,5,12; 3,5,13; 3,6,7;

3,6,8; 3,6,9; 3,6,10; 3,6,11; 3,6,12; 3,6,13; 3,7,8; 3,7,9; 3,7,10; 3,7,11; 3,7,12; 3,7,13; 3,8,9;

3,8,10; 3,8,11; 3,8,12; 3,8,13; 3,9,10; 3,9,11; 3,9,12; 3,9,13; 3,10,11; 3,10,12; 3,10,13;

3,11,12; 3,11,13; 3,12,13; 4,5,6; 4,5,7; 4,5,8; 4,5,9; 4,5,10; 4,5,11; 4,5,12; 4,5,13; 4,6,7; 4,6,8;

4,6,9; 4,6,10; 4,6,11; 4,6,12; 4,6,13; 4,7,8; 4,7,9; 4,7,10; 4,7,11 ; 4,7,12; 4,7,13; 4,8,9; 4,8,10; 4,8,11; 4,8,12; 4,8,13; 4,9,10; 4,9,11; 4,9,12; 4,9,13; 4,10,11; 4,10,12; 4,10,13; 4,11,12; 4,11,13; 4,12,13; 5,6,7; 5,6,8; 5,6,9; 5,6,10; 5,6,11; 5,6,12; 5,6,13; 5,7,8; 5,7,9; 5,7,10; 5,7,1 ; 5,7,12; 5,7,13; 5,8,9; 5,8,10; 5,8,11; 5,8,12; 5,8,13; 5,9,10; 5,9,11; 5,9,12; 5,9,13; 5,10,11; 5,10,12; 5,10,13; 5,11,12; 5,11,13; 5,12,13, 6,7,8; 6,7,9; 6,7,10; 6,7,11; 6,7,12; 6,7,13; 6,8,9; 6,8,10; 6,8,11; 6,8,12; 6,8,13; 6,9,10; 6,9, 1; 6,9,12; 6,9,13; 6,10,11; 6,10,12; 6,10,13;

6,11,12; 6,11,13; 6,12,13; 7,8,9; 7,8,10; 7,8,11; 7,8,12; 7,8,13; 7,9,10; 7,9,11; 7,9,12; 7,9,13; 7,10,11; 7,10,12; 7,10,13; 7,11,12; 7,11,13; 7,12,13; 8,9,10; 8,9,11; 8,9,12; 8,9,13; 8,10,11; 8,10,12; 8,10,13; 8,11,12; 8,11,13; 8,12,13; 9,10,11; 9,10,12; 9,10,13; 9,11,12; 9,11,13; 9,12,13; 10,11,12; 10,11,13; 10,12,13; and 11,12,13. [0095] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of one of the following sets of four analvtes in a cellular extract, wherein "1" =

HER1, "2" = HER2, "3" = p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF1R, "7" = cKit,

"8" = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11" = p70S6K, "12" = VEGFR (e.g., VEGFRl, 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" =

Erk: 1,2,3,4; 1,2,3,5; 1,2,3,6; 1,2,3,7; 1,2,3,8; 1,2,3,9; 1,2,3,10; 1,2,3,11; 1,2,3,12; 1,2,3,13;

1,3,4,5; 1,3,4,6; 1,3,4,7; 1,3,4,8; 1,3,4,9; 1,3,4,10; 1,3,4,11; 1,3,4,12; 1,3,4,13; 1,4,5,6;

1,4,5,7; 1,4,5,8; 1,4,5,9; 1,4,5,10; 1,4,5,11; 1,4,5,12; 1,4,5,13; 1,5,6,7; 1,5,6,8; 1,5,6,9;

1,5,6,10; 1,5,6,11; 1,5,6,12; 1,5,6,13; 1,6,7,8; 1,6,7,9; 1,6,7,10; 1,6,7,11; 1,6,7,12; 1,6,7,13; 1,7,8,9; 1,7,8,10; 1,7,8,11; 1,7,8,12; 1,7,8,13; 1,8,9,10; 1,8,9,11; 1,8,9,12; 1,8,9,13; 1,9,10,11;

1,9,10,12; 1,9,10,13; 1,10,11,12; 1,10,11,13; 1,11,12,13; 2,3,4,5; 2,3,4,6; 2,3,4,7; 2,3,4,8;

2,3,4,9; 2,3,4,10; 2,3,4,11; 2,3,4,12; 2,3,4,13; 2,4,5,6; 2,4,5,7; 2,4,5,8; 2,4,5,9; 2,4,5,10;

2,4,5,11; 2,4,5,12; 2,4,5,13; 2,5,6,7; 2,5,6,8; 2,5,6,9; 2,5,6,10; 2,5,6,11; 2,5,6,12; 2,5,6,13;

2,6,7,8; 2,6,7,9; 2,6,7,10; 2,6,7,11; 2,6,7,12; 2,6,7,13; 2,7,8,9; 2,7,8,10; 2,7,8,11; 2,7,8,12; 2,7,8,13; 2,8,9,10; 2,8,9,11; 2,8,9,12; 2,8,9,13; 2,9,10,11; 2,9,10,12; 2,9,10,13; 2,10,11,12;

2,10,11,13; 2,11,12,13; 3,4,5,6; 3,4,5,7; 3,4,5,8; 3,4,5,9; 3,4,5,10; 3,4,5,11; 3,4,5,12; 3,4,5,13;

3,5,6,7; 3,5,6,8; 3,5,6,9; 3,5,6,10; 3,5,6,11; 3,5,6,12; 3,5,6,13; 3,6,7,8; 3,6,7,9; 3,6,7,10;

3,6,7,11; 3,6,7,12; 3,6,7,13; 3,7,8,9; 3,7,8,10; 3,7,8,11; 3,7,8,12; 3,7,8,13; 3,8,9,10; 3,8,9,11;

3,8,9,12; 3,8,9,13; 3,9,10,11; 3,9,10,12; 3,9,10,13; 3,10,11,12; 3,10,11,13; 3,11,12,13;

4,5,6,7; 4,5,6,8; 4,5,6,9; 4,5,6,10; 4,5,6,11; 4,5,6,12; 4,5,6,13; 4,6,7,8; 4,6,7,9; 4,6,7,10;

4,6,7,11; 4,6,7,12; 4,6,7,13; 4,7,8,9; 4,7,8,10; 4,7,8,11; 4,7,8,12; 4,7,8,13; 4,8,9,10; 4,8,9,1 ;

4,8,9,12; 4,8,9,13; 4,9,10,11; 4,9,10,12; 4,9,10,13; 4,10,11,12; 4,10,11,13; 4,11,12,13;

5,6,7,8; 5,6,7,9; 5,6,7,10; 5,6,7,11; 5,6,7,12; 5,6,7,13; 5,7,8,9; 5,7,8,10; 5,7,8,11; 5,7,8,12;

5,7,8,13; 5,8,9,10; 5,8,9,11; 5,8,9,12; 5,8,9,13; 5,9,10,11; 5,9,10,12; 5,9,10,13; 5,10,11,12; 5,10,11,13; 5,11,12,13; 6,7,8,9; 6,7,8,10; 6,7,8,11; 6,7,8,12; 6,7,8,13; 6,8,9,10; 6,8,9,11; 6,8,9,12; 6,8,9,13; 6,9,10,11; 6,9,10,12; 6,9,10,13; 6,10,11,12; 6,10,11,13; 6,11,12,13;

7,8,9,10; 7,8,9,11; 7,8,9,12; 7,8,9,13; 7,9,10,11; 7,9,10,12; 7,9,10,13; 7,10,11,12; 7,10,11,13; 7,11,12,13; 8,9,10,11; 8,9,10,12, 8,9,10,13; 8,10,11,12; 8,10,11,13; 8,11,12,13; 9,10,11,12; 9,10,11,13; 9,11,12,13; and 10,11,12,13.

[0096] In another embodiment, the present invention comprises determining the expression level {e.g., total amount) and/or activation level {e.g., level of phosphorylation or complex formation) of any possible combination of five of the following analytes: "1" ^:=: FIERI, "2" = HER2, "3" - p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF1R, "7" - cKit, "8" = PI3K {e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11" = p70S6K, "12" = VEGFR {e.g., VEGFRI , 2, and/or 3) and/or PDGFR {e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of five analytes may comprise one of the following: 1,2,3,4,5; 2,3,4,5,6; 3,4,5,6,7; 4,5,6,7,8; 5,6,7,8,9; 6,7,8,9,10; 7,8,9,10,11; 8,9,10,11,12; or 9,10,11,12,13. [0097] In another embodiment, the present invention comprises determining the expression level {e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of six of the following analytes: "1" = HER1, "2" = HER2, "3" = p95HER2, "4" = HER3, "5^"' = c-Met, "6" = 1GF1R, "7" = cKit, "8^"' = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11" = p70S6K, "12" = VEGFR (e.g., VEGFRI, 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of six analytes may comprise one of the following:

1,2,3,4,5,6; 2,3,4,5,6,7; 3,4,5,6,7,8; 4,5,6,7,8,9; 5,6,7,8,9,10; 6,7,8,9,10,11; 7,8,9,10,11,12; or 8,9,10,11,12,13.

[0098] In another embodiment, the present invention comprises determining the expression level (e.g.. total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of seven of the following analytes: "1" = HER1, "2" = HER2, "3" = p95HER2, "4" = HERS, "5" = c-Met, "6" = IGFIR, "7" = cKt, "8" = PI3K {e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11" = p70S6K, "12" = VEGFR (e.g., VEGFRI , 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of seven analytes may comprise one of the following:

1,2,3,4,5,6,7; 2,3,4,5,6,7,8; 3,4,5,6,7,8,9; 4,5,6,7,8,9,10; 5,6,7,8,9,10,11; 6,7,8,9,10,11,12; or 7,8,9,10,11,12,13. [0099] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of eight of the following analytes: "1" = HER1, "2" = HER2, "3" = p95HER2, "4" = HERS, "5" = c-Met, "6" = IGF 1R, "7" = cKit, "8" = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "11 " = p70S6K, "12" = VEGFR (e.g., VEGFRl , 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of eight analytes may comprise one of the following: 1,2,3,4,5,6,7,8; 2,3,4,5,6,7,8,9: 3,4,5,6,7,8,9, 10; 4,5,6,7,8,9, 10, 1 1 ; 5,6,7,8,9, 10, 1, 12; or 6,7,8,9, 10, 1 1 , 12, 13. [0100] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of nine of the following analytes: "1" = FIERI, "2" = HER2, "3" = p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF 1R, "7" = cKit, "8^"' = PI3K (e.g., PIK3CA and/or PIK3R1 ), "9" = She, "10" = Akt, "1 1" = p70S6 , "12" = VEGFR (e.g., VEGFRl, 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of nine analytes may comprise one of the following: 1,2,3,4,5,6,7,8,9; 2,3,4,5,6,7,8,9, 10; 3,4,5,6,7,8,9, 10, 1 1 ; 4,5,6,7,8,9, 10, 1 1 , 12; or

5,6,7,8,9, 10, 1 1, 12, 13.

[0101] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of ten of the following analytes: "1 " = HER1 , "2" = HER2, "3" - p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF 1R, "7" - cKit, "8" = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "1 1 " = p70S6K, "12" = VEGFR (e.g., VEGFRl , 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination often analytes may comprise one of the following:

1,2,3,4,5,6,7,8,9, 10; 2,3,4,5,6,7,8,9, 10, 1 1 ; 3,4,5,6,7,8,9, 10, 1 1, 12; or 4,5,6,7,8,9, 10, 1 1 , 12, 13.

[0102] In another embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of any possible combination of eleven of the following analytes: "1" = HER1, "2" - FIER2, "3" = p95HER2, "4" = HER3, "5" - c-Met, "6" = IGFIR, "7" = cKit, "8" - PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "1 1" = p70S6K, "12" = VEGFR (e.g. , VEGFRl, 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. As non- limiting examples, the combination of eleven analytes may comprise one of the following: 1,2,3,4,5,6,7,8,9, 10, 1 1; 2,3,4,5,6,7,8,9, 10, 1 1, 12; or 3,4,5,6,7,8,9, 10, 1 1, 12, 13. [0103] In yet another embodiment, the present invention comprises determ ining the expression level {e.g.. total amount) and/or activation level {e.g., level of phosphorylation or complex formation) of any possible combination of twelve of the following analytes: '^"1" =^: HERl, "2" = HER2, "3" = p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF IR, "7" = cKit, "8" = PI3K {e.g., PIK3CA and/or PIK3R1 ), "9" = She, "10" = Akt, "1 1" = p70S6 , "12" = VEGFR {e.g., VEGFR1 , 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" - Erk. As non-limiting examples, the combination of twelve analytes may comprise one of the following: 1,2,3,4,5,6,7,8,9, 10, 1 1 , 12; or 2,3,4,5,6,7,8,9, 10, 1 1, 12, 13 ,

[0104] In still yet another embodiment, the present invention comprises determining the expression level {e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of all thirteen of the following analytes: " I " = HER ! , "2" = HER2, "3" - p95HER2, "4" = HER3, "5" = c-Met, "6" = IGF IR, "7" - cKit, "8" = PI3K (e.g., PIK3CA and/or PIK3R1), "9" = She, "10" = Akt, "1 1" = p70S6K, "12" = VEGFR (e.g., VEGFR 1, 2, and/or 3) and/or PDGFR (e.g., PDGFRA and/or B), and "13" = Erk. [0105] In one particular embodiment, the present invention comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of at least one, two, three, four, five, six, seven, eight, nine, or ten of the following analytes: HERl, HER2, HER3, cMET, cKIT, IGF-1R, PI3K (e.g.. P1K3CA and/or PIK3R1), AKT, ERK (e.g., ERKl (MAPK3) and/or ERK2 (MAPKl )), and SHC, [0106] In certain preferred embodiments, the present invention comprises (i) determining the expression level of at least one or more of HER l, HER2, HER3, cMET, cKIT, and/or IGF- 1 R and/or (ii) determining the activation level of at least one or more of HERl , HER2, HER3, cMET, cKIT, IGF-1R, PI3K, AKT, ERK, and/or SHC. In some embodiments, the activation level corresponds to a level of phosphorylation of HERl, HER2, HER3, cMET, cKIT, IGF-1R, AKT, ERK, and/or SHC. In certain other embodiments, the activation level corresponds to a level of a PI3K complex. Examples of PI3 complexes include, without limitation, one or more complexes comprising a dimerized receptor tyrosine kinase pair, a PI3K p85 subunit (e.g., PIK3R1), and a PI3K p i 10 subunit (e.g., an a or β subunit such as PIK3CA or PIK3CB); see, for example, U.S. Provisional Application No. 61 /530,621 , filed September 2, 201 1, the disclosure of which is herein incorporated by reference in its entirety for ail purposes.

[0107] In certain embodiments, the present invention further comprises determining the expression level (e.g., total amount) and/or activation level {e.g., level of phosphorylation or complex formation) of one or more (e.g. , at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, or more) additional analytes in a cellular extract. In some embodiments, the one or more (e.g., at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, or more) additional analytes comprises one or more signal transduction molecules selected from the group consisting of receptor tyrosine kinases, nonreceptor tyrosine kinases, tyrosine kinase signaling cascade components, nuclear hormone receptors, nuclear receptor coactivators, nuclear receptor repressors, and combinations thereof. [0108] In particular embodiments, the present invention further comprises determining the expression level (e.g., total amount) and/or activation level (e.g., level of phosphorylation or complex formation) of one or any combination of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, or more of the following additional analytes in a cellular extract: HER4, MEK, PTEN, SGK3, 4E-BP1, PDK1 , PDK2, GSK-3P, Raf, SRC, NFkB-IkB, niTOR, EPH-A, EPH-B, EPH-C, EPH-D, FLT-3, TIE-1, TIE-2, c-FMS, Abl, FTL 3, RET, FGFR1, FGFR2, FGFR3, FGFR4, ER, PR, NCOR, AIBL RON, PIP2, ΡΪΡ3, p27, protein tyrosine phosphatases (e.g., PTP1B, PTPN13, BDP1, etc.), receptor dimers, and combinations thereof,

[0109] In certain aspects, the present invention provides methods for the rational selection of one or a combination of anticancer drugs tailored to target one or more signal transduction pathway components with higher levels of expression and/or activation detected in a cancer cell obtained from a patient with a somatic mutation in an oncogene. In some embodiments, the methods of the present invention rely on the detection or measurement of higher levels of expression and/or activation of non-ErbB receptor tyrosine kinases (RTKs) such as cMET and IGF IR in KRAS mutant patients compared to KRAS wild-type patients. In particular embodiments, the present invention enables the identification of KRAS mutant patients with both ErbB-driven and ErbB-independent RTK expression and/or activation who would benefit from combination therapy and the selection of appropriate therapies targeting ErbB RTKs (e.g., HERL HER2, HERS, and/or HER4) and non-ErbB RTKs (e.g., cMET and/or IGF1R).

[0110] In one aspect, the present invention provides a method for determining whether an anticancer drug targeting one or more non-ErbB receptor tyrosine kinases (RTKs) should be administered for the treatment of colorectal cancer in a subject with a. KRAS mutation, the method comprising: (a) detecting the expression level and/or activation level of one or more non- ErbB RTKs in a cancer cell obtained from the subject; and

(b) determining that an anticancer drug targeting one or more non-ErbB RTKs should be administered to the subject when a higher expression level or activation level of one or more non-ErbB RTKs is detected compared to the expression level or activation level of the same non-ErbB RTKs in a cancer cell from a KRAS wild-type subject.

[0111] In certain embodiments, a higher expression level or activation level of one or more non-ErbB RTKs is considered to be present in the cancer cell from the KRAS mutant subject when the expression or activation level is at least about 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8,5, 9, 9.5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 100-fold higher (e.g., about 1.5-3, 2- 3, 2-4, 2-5, 2-10, 2-20, 2-50, 3-5, 3-10, 3-20, 3-50, 4-5, 4-10, 4-20, 4-50, 5-10, 5-15, 5-20, or 5-50-fold higher) than the expression level or activation level of the same non-ErbB RTKs in the cancer cell from the ATMS wild-type subject. In some embodiments, a higher expression level or activation level of one or more non-ErbB RTKs is considered to be present in the cancer cell from the KRAS mutant subject when there is a statistically significant difference between the expression or activation level of the same non-ErbB RTKs in the KRAS mutant subject compared to the KRA S ^' wild-type subject. In certain instances, the differences can be considered as being statistically significant when the P value is less than about 0.1 {e.g., P < 0.1, /' < 0.05, P < 0.01, P≤ 0.005, P≤ 0.001, etc.).

[0112] In some embodiments, the one or more non-ErbB RTKs include, but are not limited to, cMET, IGFIR, FGFRs (e.g., FGFR1, FGFR2, FGFR3, and/or FGFR4), VEGFRs (e.g.. VEGFRI, VEGF 2, and/or VEGFRS), and combinations thereof. In certain instances, the expression level of cMET and/or IGFI R is higher in the cancer cell obtained from the KRAS mutant subject compared to the cancer ceil from the KIMS wild-type subject. In certain other instances, the activation level of cMET is higher in the cancer cell obtained from the KRAS mutant subject compared to the cancer ceil obtained from the KRAS wild-type subject. In yet other instances, the KRAS mutation is selected from the group consisting of G12S, G12D, G12A, G12V, G12R, G12C, G13D, and combinations thereof. [0113] In certain embodiments, the cancer cell is a circulating tumor cell (CTC) or a fine needle aspirate (FNA) ceil obtained from a colorectal tumor. In some instances, the tumor is primary tumor tissue or metastatic tumor tissue. [0114] In other embodiments, the method further comprises detecting the expression level and/or activation level of one or more ErbB receptor tyrosine kinases (RTKs). In particular embodiments, the expression level and/or activation level of the one or more ErbB RTKs is higher in the cancer cell obtained from, the KRAS mutant subject as compared to a reference expression level and/or activation level of the same ErbB RTKs, e.g., in a cancer cell from a KRAS wild-type subject, in a normal (e.g., non-cancerous) cell from a KRAS mutant subject, etc. In certain instances, the one or more ErbB RTKs include, but are not limited to, HERI, HER2, HER3, HER , and combinations thereof. In other embodiments, the method further comprises determining that an anticancer drug targeting one or more ErbB RTKs should be administered to the subject.

[0115] In further embodiments, the anticancer drug targeting one or more non-ErbB RTKs and/or targeting one or more ErbB RTKs includes, but is not limited to, any of the anticancer drags described herein, such as, e.g., monoclonal antibodies, tyrosine kinase inhibitors, antiproliferative agents, chemotherapeutic agents, and combinations thereof. As a non-limiting example, a combination of ErbB RT -targeting therapy with cMET-targeting therapy (e.g.. one or more cMET inhibitors) may benefit subjects with concomitant ErbB RTK and cMET expression and/or activation .

[0116] In other embodiments, the method further comprises administering the anticancer drag targeting one or more of the non-ErbB RTKs to the KRAS mutant subject when a higher expression or activation level of the non-ErbB RTKs is detected compared to the expression or activation level of the same non-ErbB RTKs in the cancer cell from the KIMS wild-type subject. In aspects of the present invention wherein the method further comprises detecting the expression level and/or activation level of one or more ErbB RTKs in the cancer cell from the KRAS mutant subject, the method can further comprise administering the anticancer drug targeting one or more of the ErbB RTKs to the subject when a higher expression or activation level of the ErbB RTKs is detected compared to the expression or activation level of the same ErbB RTKs.

[0117] In some embodiments, determining the expression level of the one or m ore analytes comprises detecting the total amount of each of the one or more analytes in the cellular extract with one or more antibodies specific for the corresponding analyte. In particular embodiments, the antibodies bind to the analyte irrespective of the activation state of the analyte to be detected, i.e., the antibodies detect both the non-activated and activated forms of the analyte. [0118] Total expression level and/or status can be determined using any of a variety of techniques. In certain embodiments, the total expression level and/or status of each of the one or more analytes such as signal transduction molecules in a sample is detected with an immunoassay such as a single detection assay or a proximity dual detection assay (e.g., a Collaborative Enzyme Enhanced Reactive Immunoassay (CEER)) as described herein.

[0119] In certain embodiments, determining the expression (e.g.. total) levels of the one or more analytes comprises:

(i) incubating (e.g., contacting) a cellular extract produced from the cell with one or a plurality of dilution series of capture antibodies (e.g., capture antibodies specific for one or more analytes) to fonn a plurality of captured analytes, wherein the capture antibodies are restrained on a solid support (e.g., to transform the analytes present in the cellular extract into complexes of captured analytes comprising the analytes and capture antibodies);

(ii) incubating (e.g., contacting) the plurality of captured analytes with detection antibodies comprising one or a plurality of first and second activation state- independent antibodies specific for the corresponding analytes (e.g., first and second activation state-independent antibodies specific for the one or more analytes) to fonn a plurality of detectable captured analytes (e.g., to transform the complexes of captured analytes into complexes of detectable captured analytes comprising the captured analytes and detection antibodies), wherein the first activation state-independent antibodies are labeled with a

facilitating moiety, the second activation state -independent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(iii) incubating (e.g., contacting) the plurality of detectable captured analytes with a second member of the signal amplification pair to generate an amplified signal; and

(iv) detecting the amplified signal generated from the first and second members of the signal amplification pair.

[0120] In certain other embodiments, determining the expression (e.g., total) levels of the one or more analytes that are truncated receptors (e.g., p95HER2) comprises: (i) incubating (e.g., contacting) a cellular extract produced from the cell with a plurality of beads specific for an extracellular domain (ECD) binding region of a full-length receptor (e.g., full -length HER2);

(is) removing the plurality of beads from the cellular extract, thereby removing the full-length receptor (e.g., full-length HER2)to form a cellular extract devoid of the full-length receptor (e.g.. full-length HER2) (e.g., to transform the cellular extract into a cellular extract devoid of a specific full-length receptor or family of full-length receptors);

(iii) incubating (e.g., contacting) the cellular extract devoid of the full-length

receptor (e.g., full-length HER2) with one or a plurality of capture antibodies specific for an intracellular domain (ICD) bin ding region of the full -length receptor (e.g., full-length HER2) to form a plurality of captured truncated receptors, wherein the capture antibodies are restrained on a solid support (e.g., to transform the truncated receptors present in a full-length receptor- depleted cellular extract into complexes of truncated receptors and capture antibodies);

(iv) incubating the plurality of captured truncated receptors with detection

antibodies comprising one or a plurality of first and second activation state- independent antibodies specific for an ICD binding region of the full-length receptor (e.g., full-length HER2) to form a plurality of detectable captured truncated receptors (e.g.. to transform the complexes of captured truncated receptors into complexes of detectable captured truncated receptors comprising the captured truncated receptors and detection antibodies), wherein the first activation state -independent antibodies are labeled with a

facilitating moiety, the second activation state-independent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(v) incubating (e.g., contacting) the plurality of detectable captured truncated receptors with a second member of the signal amplification pair to generate an amplified signal; and

(vi) detecting the amplified signal generated from the first and second members of the signal amplification pair. [0121] The first activation state-independent antibodies may be directly labeled with the facilitating moiety or indirectly labeled with the facilitating moiety, e.g., via hybridization between an oligonucleotide conjugated to the first activation state-independent antibodies and a complementary oligonucleotide conjugated to the facilitating moiety. Similarly, the second activation state-independent antibodies may be directly labeled with the first member of the signal amplification pair or indirectly labeled with the first member of the signal

amplification pair, e.g., via binding between a first member of a binding pair conjugated to the second activation state-independent antibodies and a second member of the binding pair conjugated to the first member of the signal amplification pair. In certain instances, the first member of the binding pair is biotin and the second member of the binding pair is an avidin such as streptavidm or neutravidin.

[0122] In some embodiments, the facilitating moiety may be, for example, glucose oxidase. In certain instances, the glucose oxidase and the first activation state-independent antibodies can be conjugated to a sulfhydry] -activated dextran molecule as described in, e.g., Examples 16-17 of PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes. The sulfhydryl-activated dextran molecule typically has a molecular weight of about 500kDa (e.g., about 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, or 750kDa). In other embodiments, the oxidizing agent may be, for example, hydrogen peroxide (H₂O₂). In yet other embodiments, the first member of the signal amplification pair may be, for example, a peroxidase such as horseradish peroxidase (HRP). In further embodiments, the second member of the signal amplification pair may be, for example, a tyramide reagent {e.g., biotin-tyramide). Preferably, the amplified signal is generated by peroxidase oxidization of biotin-tyramide to produce an activated tyramide (e.g., to transform the biotin-tyramide into an activated tyramide). The activated tyramide may be directly detected or indirectly detected, e.g., upon the addition of a signal-detecting reagent. Non-limiting examples of signal-detecting reagents include streptavidin-labeled fluorophores and combinations of streptavidin-labeled peroxidases and chromogenic reagents such as, e.g., 3,3',5,5'-tetramethylbenzidine (TMB).

[0123] In certain instances, the horseradish peroxidase and the second activation state- independent antibodies can be conjugated to a sulfhydry] -activated dextran molecule. The sulfhydryl-activated dextran molecule typically has a molecular weight of about 70kDa (e.g., about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or lOOkDa).

[0124] The truncated receptor is typically a fragment of the full-length receptor and shares an intracellular domain (ICD) binding region with the full-length receptor. In certain embodiments, the full-length receptor compr ses an extracellular domain (ECD) binding region, a transmembrane domain, and an intracellular domain (ICD) binding region. Without being bound to any particular theory, the trancated receptor may arise through the proteolytic processing of the ECD of the full-length receptor or by alternative initiation of translation from methionine residues that are located before, within, or after the transmembrane domain, e.g., to create a truncated receptor with a shortened ECD or a truncated receptor comprising a membrane-associated or cytosolic 1CD fragment.

[0125] In certain preferred embodiments, the truncated receptor is p95HER2 and the corresponding full-length receptor is HER2. However, one skilled in the art will appreciate that the methods described herein for detecting truncated proteins can be applied to a number of different proteins including, but not limited to, the EGFR VIIT mutant (implicated in glioblastoma, colorectal cancer, etc.), other truncated receptor tyrosine kinases, caspases, and the like. Example 12 of PCX Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes, provides an exemplary embodiment of the assay methods of the present invention for detecting truncated receptors such as p95HER2 in cells using a multiplex, high-throughput, proximity dual detection microarray ELISA having superior dynamic range.

[0126] In some embodiments, the plurality of beads specific for an ECD binding region comprises a streptavidin-biotin pair, wherein the streptavidin is attached to the bead and the biotin is attached to an antibody. In certain instances, the antibody is specific for the ECD binding region of the full-length receptor {e.g., full-length HER2).

[0127] In some embodiments, each dilution series of capture antibodies comprises a series of descending capture antibody concentrations. In certain instances, the capture antibodies are serially diluted at least 2-fold (e.g., 2, 5, 10, 20, 50, 100, 500, or 1000-fold) to produce a dilution series comprising a set number (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or more) of descending capture antibody concentrations which are spotted onto an array. Preferably, at least 2, 3, 4, 5, or 6 replicates of each capture antibody dilution are spotted onto the array.

[0128] In other embodiments, the solid support comprises glass (e.g., a glass slide), plastic, chips, pins, filters, beads, paper, membrane (e.g.. nylon, nitrocellulose, polyvinyiidene fluoride (PVDF), etc.), fiber bundles, or any other suitable substrate. In a preferred embodiment, the capture antibodies are restrained (e.g., via covalent or noncovalent interactions) on glass slides coated with a nitrocellulose polymer such as, for example, FAST^® Slides, which are commercially available from Whatman Inc. (Florham Park, NJ). Exemplary methods for constructing antibody arrays suitable for use in the invention are described, e.g., in PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes.

[0129] In further embodiments, determining the activation levels of the one or more analytes comprises detecting a phosphorylation level of the one or more analytes in the cellular extract with antibodies specific for the phosphorylated form of each of the analytes to be detected.

[0130] Phosphorylation levels and/or status can be determined using any of a variety of techniques. For example, it is well known in the art that phosphorylated proteins can be detected via immunoassays using antibodies that specifically recognize the phosphorylated form of the protein (see, e.g., Lin et al, Br. J. Cancer, 93: 1372-1381 (2005)). Immunoassays generally include immunoblotting (e.g. , Western blotting), RIA, and ELISA. More specific types of immunoassays include antigen capture/antigen competition, antibody capture/antigen competition, two-antibody sandwiches, antibody capture/antibody excess, and antibody capture/antigen excess. Methods of making antibodies are described herein and in Harlow and Lane, Antibodies: A Laborator ' Manual, 1988, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, LISA. Phospho-specifc antibodies can be made de novo or obtained from commercial or noncommercial sources. Phosphorylation levels and/or status can also be determined by metabolically labeling cells with radioactive phosphate in the form of [y- ³²P]ATP or jv~^j3P]ATP. Phosphorylated proteins become radioactive and hence traceable and quantifiable through scintillation counting, radiography, and the like (see, e.g., Wang et al. , J. Biol. Chem., 253:7605-7608 (1978)). For example, metabolically labeled proteins can be extracted from cells, separated by gel electrophoresis, transferred to a membrane, probed with an antibody specific for a particular analyte and subjected to autoradiography to detect ³²P or ³³P. Alternatively, the gel can be subjected to autoradiography prior to membrane transference and antibody probing.

[0131] In particular embodiments, the activation (e.g., phosphorylation) level and/or status of each of the one or more analytes in a sample is detected with an immunoassay such as a single detection assay or a proximity dual detection assay (e.g.. a Collaborative Enzyme Enhanced Reactive Immunoassay (CEER)) as described herein.

[0132] In certain embodiments, determining the activation (e.g., phosphorylation) level of the one or more analytes comprises: (i) incubating (e.g., contacting) a cellular extract produced from, the cell with a dilution series of capture antibodies (e.g., capture antibodies specific for one or more analytes) to form a plurality of captured analytes, wherein the capture antibodies are restrained on a solid support (e.g., to transform the analytes present in the cellular extract into complexes of captured analytes comprising the analytes and capture antibodies);

(ii) incubating (e.g., contacting) tlie plurality of captured analytes with detection antibodies comprising activation state-independent antibodies specific for the corresponding analytes (e.g.. activation state-independent antibodies specific for tlie one or more analytes) and activation state -dependent antibodies specific for the corresponding analytes (e.g., activation state-dependent antibodies specific for the one or more analytes) to form a plurality of detectable captured analytes (e.g., to transform the complexes of captured analytes into complexes of detectable captured analytes comprising the captured analytes and detection antibodies),

wherein the activation state-independent antibodies are labeled with a facilitating moiety, the activation state -dependent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(iii) incubating (e.g., contacting) tlie plurality of detectable captured analytes with a second member of the signal amplification pair to generate an amplified signal; and

[0133] In certain other embodiments, determining the activation (e.g., phosphorylation) level of tlie one or more analytes that are truncated receptors (e.g., p95HER2) comprises:

(i) incubating (e.g., contacting) a cellular extract produced from the cell with a plurality of beads specific for an extracellular domain (ECD) binding region of a full-length receptor (e.g., full-length HER2);

(ii ) removing the plurality of beads from the cellular extract, thereby removing the full-length receptor (e.g., full-length HER2) to form a cellular extract devoid of the full-length receptor (e.g., full-length HER2) (e.g., to transform the cellular extract into a cellular extract devoid of a specific full -length receptor or family of full-length receptors);

(iii) incubating (e.g.. contacting) the cellular extract devoid of the full-length receptor (e.g., full-length HER2) with a plurality of capture antibodies specific for an intracellular domain (ICD) binding region of the full-length receptor (e.g., full-length HER2) to form a plurality of captured truncated receptors, wherein the capture antibodies are restrained on a solid support (e.g., to transform the truncated receptors present in a full-length receptor-depleted cellular extract into complexes of truncated receptors and capture antibodies);

(iv) incubating (e.g.. contacting) the plurality of captured truncated receptors with detection antibodies comprising activation state-independent antibodies and activation state-dependent antibodies specific for an ICD binding region of the full-length receptor (e.g., full-length HER2) to form a plurality of detectable captured truncated receptors (e.g., to transform the complexes of captured truncated receptors into complexes of detectable captured truncated receptors comprising the captured truncated receptors and detection antibodies), wherein the activation state-independent antibodies are labeled with a facilitating moiety, the activation state-dependent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(vi) detecting the amplified signal generated from the first and second members of the signal amplification pair.

The activation state-mdependent antibodies may be directly labeled with the facilitating moiety or indirectly labeled with the facilitating moiety, e.g., via hybridization between an oligonucleotide conjugated to the activation state-independent antibodies and a complementary oligonucleotide conjugated to the facilitating moiety. Similarly, the activation state-dependent antibodies may be directly labeled with the fi rst member of the signal amplification pair or indirectly labeled with the first member of the signal amplification pair, e.g., via binding between a first member of a binding pair conjugated to the activation state -dependent antibodies and a second member of the binding pair conjugated to the first member of the signal amplification pair. In certain instances, the first member of the binding pair is biotin and the second member of the bind ing pair is an avidin such as streptavidin or neutravidin.

[0135] In some embodiments, the facilitating moiety may be, for example, glucose oxidase. In certain instances, the glucose oxidase and the activation state-independent antibodies can be conjugated to a sulfhydryl-activated dextran molecule as described in, e.g., Examples 16- 17 of PCT Publication No. WQ2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes. The suimydryl-activated dextran molecule typically has a molecular weight of about 500kDa (e.g., about 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, or 750kDa). In other embodiments, the oxidizing agent may be, for example, hydrogen peroxide (H₂O₂). In yet other embodiments, the first member of the signal amplification pair may be, for example, a peroxidase such as horseradish peroxidase (HRP), In further embodiments, the second member of the signal amplification pair may be, for example, a tyramide reagent (e.g., biotin-tyramide). Preferably, the amplified signal is generated by peroxidase oxidization of biotin-tyramide to produce an activated tyramide (e.g., to transform the biotin-tyramide into an activated tyramide). The activated tyramide may be directly detected or indirectly detected, e.g.. upon the addition of a signal-detecting reagent. Non-limiting examples of signal-detecting reagents include streptavidin-labeled fluorophores and combinations of streptavidin-labeled peroxidases and chromogenic reagents such as, e.g., 3,3',5,5'-tetramethyibenzidine (TMB).

[0136] In certain instances, the horseradish peroxidase and the activation state-dependent antibodies can be conjugated to a sulfhydryl-activated dextran molecule. The sulfhydryl- activated dextran molecule typically has a molecular weight of about 70kDa (e.g., about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or lOOkDa). [0137] The truncated receptor is typically a fragment of the full-length receptor and shares an intracellular domain (ICD) binding region with the full-length receptor. In certain embodiments, the full-length receptor comprises an extracellular domain (BCD) binding region, a transmembrane domain, and an intracellular domain (ICD) binding region. Without being bound to any particular theory, the truncated receptor may arise through the proteolytic processing of the ECD of the full-length receptor or by alternative initiation of translation from methionine residues that are located before, within, or after the transmembrane domain, e.g., to create a truncated receptor with a shortened ECD or a truncated receptor comprising a membrane-associated or cytosolic ICD fragment. [0138] In certain preferred embodiments, the truncated receptor is p95HER2 and the corresponding full-length receptor is HER2. However, one skilled in the art will appreciate that the methods described herein for detecting tamcated proteins can be applied to a number of different proteins including, but not limited to, the EGFR VIII mutant (implicated in glioblastoma, colorectal cancer, etc.), other truncated receptor tyrosine kinases, caspases, and the like. Example 12 of PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes, provides an exemplary em bodiment of the assay methods of the present invention for detecting tamcated receptors such as p95HER2 in cells using a multiplex, high-throughput, proximity dual detection microarray ELISA having superior dynamic range.

[0139] In some embodiments, the plurality of beads specific for an ECD binding region comprises a streptavidin-hiotin pair, wherein the strepiavidin is attached to the bead and the biotin is attached to an antibody. In certain instances, the antibody is specific for the ECD binding region of the full-length receptor (e.g. , full-length HER2). [0140] In some embodiments, each dilution series of capture antibodies comprises a series of descending capture antibody concentrations. In certain instances, the capture antibodies are serially diluted at least 2-fold (e.g., 2, 5, 10, 20, 50, 100, 500, or 1000-fold) to produce a dilution series comprising a set number (e.g.. 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or more) of descending capture antibody concentrations which are spotted onto an array. Preferably, at least 2, 3, 4, 5, or 6 replicates of each capture antibody dilution are spotted onto the array.

[0141] In other embodiments, the solid support comprises glass (e.g., a glass slide), plastic, chips, pins, filters, beads, paper, membrane (e.g., nylon, nitrocellulose, polyvinyl idene fluoride (PVDF), etc. ), fiber bundles, or any other suitable substrate. In a preferred embodiment, the capture antibodies are restrained (e.g.. via covalent or noncovalent interactions) on glass slides coated with a nitrocellulose polymer such as, for example,

FAST® Slides, which are commercially available from Whatman Inc. (Florham Park, NJ). Exemplary methods for constructing antibody arrays suitable for use in the invention are described, e.g., in PCX Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes, IV. Single Detection Assays

[0142] In some embodiments, the assay for detecting the expression and/or activation level of one or more anaiytes of interest in a cellular extract of cells such as tumor cells is a multiplex, high-throughput two-antibody assay having superior dynamic range. As a non- limiting example, the two antibodies used in the assay can comprise: (1) a capture antibody specific for a particular analyte of interest; and (2) a detection antibody specific for an activated form of the analyte (i.e., activation state-dependent antibody). The activation state- dependent antibody is capable of detecting, for example, the phosphorylation, ubiquitination, and/or complexation state of the analyte. Alternatively, the detection antibody comprises an activation state-independent antibody, which detects the total amount of the analyte in the cellular extract. The acti vation state-independent antibody is generally capable of detecting both the activated and non-activated forms of the analyte.

[0143] In one particular embodiment, the two-antibody assay for detecting the expression or activation level of an analyte of interest comprises:

(i) incubating the cellular extract with one or a plurality of dilution series of capture antibodies to form a plurality of captured analytes;

(ii) incubating the plurality of captured analytes with detection antibodies specific for the corresponding analytes to form a plurality of detectable captured analytes, wherein the detection antibodies comprise activation state-dependent antibodies for detecting the activation (e.g., phosphorylation) level of the analyte or activation state-independent antibodies for detecting the expression level (e.g., total amount) of the analyte;

(iii) incubating the plurality of detectable captured analytes with first and second members of a signal amplification pair to generate an amplified signal; and

[0144] The two-antibody assays described herein are typically antibody -based arrays which comprise a plurality of different capture antibodies at a range of capture antibody concentrations that are coupled to the surface of a solid support in different addressable locations. Examples of suitable solid supports for use in the present invention are described above.

[0145] The capture antibodies and detection antibodies are preferably selected to minimize competition between them with respect to analyte binding (i. e., both capture and detection antibodies can simultaneously bind their corresponding signal transduction molecules).

[0146] In one embodiment, the detection antibodies comprise a first member of a binding pair (e.g., biotin) and the first member of the signal amplification pair comprises a second member of the binding pair (e.g., streptavidin). The binding pair members can be coupled directly or indirectly to the detection antibodies or to the fi rst member of the signal amplification pair using methods well-known in the art, in certain instances, the first member of the signal amplification pair is a peroxidase (e.g., horseradish peroxidase (HRP), catalase, chloroperoxidase, cytochrome c peroxidase, eosinophil peroxidase, glutathione peroxidase, lactoperoxidase, myeloperoxidase, thyroid peroxidase, deiodinase, etc. ), and the second member of the signal amplification pair is a tyramide reagent (e.g., biotin-tyramide). In these instances, the amplified signal is generated by peroxidase oxidization of the tyramide reagent to produce an activated tyramide in the presence of hydrogen peroxide (H₂O₂).

[0147] The activated tyramide is either directly detected or detected upon the addition of a signal -detecting reagent such as, for example, a streptavidin-labeled fluorophore or a combination of a streptavidin-labeled peroxidase and a chromogenic reagent. Examples of fluorophores suitable for use in the present invention include, but are not limited to, an Alexa Fluor¹* dye (e.g., Alexa Fluor*^' 555), fluorescein, fluorescein isothiocyanate (FITC), Oregon Green™; rhodamine, Texas red, tetrarhodamine isothiocynate (TRITC), a CyDye™ fluor (e.g., Cy2, Cy3, Cy5), and the like. The streptavidin label can be coupled directly or indirectly to the fluorophore or peroxidase using methods well-known in the art. Non- limiting examples of chromogenic reagents suitable for use in the present invention include 3,3 ',5,5 '-tetramethylbenzidine (TMB), 3,3 '-diaminobenzidine (DAB), 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid) (ABTS), 4-chloro-l-napthol (4CN), and/or

porphyrinogen.

[0148] An exemplary protocol for performing the two-antibody assays described herein is provided in Example 3 of PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes.

[0149] In another embodiment of a two-antibody approach, the present invention provides a method for detecting the expression or activation level of a truncated receptor, the method comprising:

(i) incubating the cellular extract with a plurality of beads specific for an

extracellular domain (ECD) binding region of a full-length receptor;

(ii) removing the plurality of beads from the cellular extract thereby removing the full-length receptor to form a cellular extract devoid of the full-length receptor;

(iii) incubating the cellular extract devoid of the full-length receptor with a dilution series of one or a plurality of capture antibodies specific for an intracellular domain (ICD) binding region of the full-length receptor to form a plurality of captured truncated receptors;

(iv) incubating the plurality of captured truncated receptors with detection

antibodies specifi c for an ICD binding region of the full-length receptor to form a plurality of detectable captured truncated receptors, wherein the detection antibodies comprise activation state-dependent antibodies for detecting the activation (e.g., phosphorylation) level of the truncated receptor or activation state-independent antibodies for detecting the expression level (e.g., total amount) of the truncated receptor;

(v) incubating the plurality of detectable captured truncated receptors with first and second members of a signal amplification pair to generate an amplified signal; and

(vi) detecting an amplified signal generated from the first and second members of the signal amplification pair. [0150] In certain embodiments, the truncated receptor is p95HER2 and the full-length receptor is HER2. In certain other embodiments, the plurality of beads specific for an extracellular domain (ECD) binding region comprises a streptavidin-biotin pair, wherein the biotin is attached to the bead and the biotin is attached to an antibody (e.g., wherein the antibody is specific for the ECD binding region of the full-length receptor). [0151] Figure 14A of PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes, shows that beads coated with an antibody directed to the extracellular domain (ECD) of a receptor of interest binds the full- length receptor (e.g., HER2), but not the truncated receptor (e.g., p95HER2) to remove any full-length receptor from the assay. Figure 14B of PCT Publication No. WO2009/108637 shows that the trancated receptor (e.g., p95HER2), once bound to a capture antibody, may then be detected by a detection antibody that is specific for the intracellular domain (ICD) of the full-length receptor (e.g. , HER2). The detection antibody may be directly conjugated to horseradish peroxidase (HRP). Tyramide signal amplification (TSA) may then be performed to generate a signal to be detected. The expression level or activation state of the truncated receptor (e.g., p95HER2) can be interrogated to determine, e.g., its total concentration or its phosphorylation state, ubiquitination state, and/or complexation state.

[0152] In another embodiment, the present invention provides kits for performing the two- antibody assays described above comprising: (a) a dilution series of one or a plurality of capture antibodies restrained on a solid support; and (b) one or a plurality of detection antibodies (e.g., activation state-independent antibodies and/or activation state-dependent antibodies). In some instances, the kits can further contain instructions for methods of using the kit to detect the expression levels and/or activation states of one or a plurality of signal transduction molecules of cells such as tumor cells. The kits may also contain any of the additional reagents described above with respect to performing the specific methods of the present invention such as, for example, first and second members of the signal amplification pair, tyramide signal amplification reagents, wash buffers, etc.

V. Proximity Dual Detection Assays

[0153] In some embodiments, the assay for detecting the expression and/or activation level of one or more analytes of interest in a cellular extract of cells such as tumor cells is a multiplex, high-throughput proximity {i.e., three -antibody) assay having superior dynamic range. As a non-limiting example, the three antibodies used in the proximity assay can comprise: (1) a capture antibody specific for a particular analyte of interest; (2) a detection antibody specific for an activated form of the analyte {i.e., activation state-dependent antibody); and (3) a detection antibody which detects the total amount of the analyte (i.e., activation state-independent antibody). The activation state -dependent antibody is capable of detecting, e.g., the phosphorylation, ubiquitination, and/or complexation state of the analyte, while the activation state-independent antibody is capable of detecting the total amount (i.e., both the activated and non-activated forms) of the analyte. [0154] In one particular embodiment, the proximity assay for detecting the activation level or status of an analyte of interest comprises:

(i) incubating the cellular extract with one or a plurality of dilution series of

capture antibodies to form a plurality of captured analytes;

(ii) incubating the plurality of captured analytes with detection antibodies

comprising one or a plurality of activation state-independent antibodies and one or a plurality of activation state-dependent antibodies specific for the corresponding analytes to form a plurality of detectable captured analytes, wherein the activation state-independent antibodies are labeled with a facilitating moiety, the activation state-dependent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(iii) incubating the plurality of detectable captured analytes with a second member of the signal amplification pair to generate an amplified signal; and (iv) detecting the amplified signal generated from, the first and second members of the signal amplification pair.

[0155] In another particular embodiment, the proximity assay for detecting the activation level or status of an analyte of interest that is a truncated receptor comprises:

(i) incubating the cellular extract with a plurality of beads specific for an

extracellular domain (ECD) binding region of a full-length receptor;

(ii) removing the plurality of beads from the cellular extract, thereby removing the full-length receptor to form a cellular extract devoid of the full-length receptor;

( in ) incubating the cellular extract devoid of the full-length receptor with one or a plurality of capture antibodies specific for an intracellular domain (ICD) binding region of the full-length receptor to form a plurality of captured truncated receptors;

(iv) incubating the plurality of captured truncated receptors with detection

antibodies comprising one or a plurality of activation state-independent antibodies and one or a plurality of activation state -dependent antibodies specifi c for an ICD binding region of the full-length receptor to form a plurality of detectable captured truncated receptors,

wherein the activation state-independent antibodies are labeled with a facilitating moiety, the activation state-dependent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(v) incubating the plurality of detectable captured truncated receptors with a second member of the signal amplification pair to generate an amplified signal; and

[0156] In certain embodiments, the truncated receptor is p95HER2 and the full-length receptor is HER2. In certain other embodiments, the plurality of beads specific for an extracellular domain (ECD) binding region comprises a streptavidin-biotin pair, wherein the biotin is attached to the bead and the biotin is attached to an antibody (e.g., wherein the antibody is specific for the ECD binding region of the full-length receptor). [0157] In alternative embodiments, the activation state-dependent antibodies can be labeled with a facilitating moiety and the activation state-independent antibodies can be labeled with a first member of a signal amplification pair.

[0158] As another non-limiting example, the three antibodies used in the proximit ' assay can comprise: (1) a capture antibody specific for a particular analyte of interest; (2) a first detection antibody which detects the total amount of the analyte (i.e., a first activation state- independent antibody); and (3) a second detection antibody which detects the total amount of the analyte (i.e., a second activation state-independent antibody). In preferred embodiments, the first and second activation state-independent antibodies recognize different (e.g., distinct) epitopes on the analyte.

[0159] In one particular embodiment, the proximity assay for detecting the expression level of an analyte of interest comprises:

capture antibodies to form a plurality of captured analytes;

(ii) incubating the plurality of captured analytes with detection antibodies

comprising one or a plurality of first and second activation state-independent antibodies specific for the corresponding analytes to form a plurality of detectable captured analytes,

wherein the first activation state-independent antibodies are labeled with a

facilitating moiety, the second activation state-mdependent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair;

(iii) incubating the plurality of detectable captured analytes with a second member of the signal amplification pair to generate an amplified signal; and

(iv) detecting the amplified signal generated from, the first and second members of the signal amplification pair.

[0160] In another particular embodiment, the proximity assay for detecting the expression level of an analyte of interest that is a truncated receptor comprises:

(i) incubating the cellular extract with a plurality of beads specific for an

extracellular domain (ECD) binding region of a full-length receptor;

(ii) removing the plurality of bead s from the cellular extract, thereby removing the full-length receptor to form a cellular extract devoid of the full-length receptor; (iii) incubating the cellular extract devoid of the full-length receptor with one or a plurality of capture antibodies specific for an intracellular domain (TCD) binding region of the full-length receptor to form a plurality of captured truncated receptors;

(iv) incubating the plurality of captured truncated receptors with detection

antibodies comprising one or a plurality of first and second activation state- independent antibodies specific for an 1CD binding region of the full-length receptor to form a plurality of detectable captured truncated receptors, wherein the first activation state-independent antibodies are labeled with a

facilitating moiety, the second activation state -independent antibodies are labeled with a first member of a signal amplification pair, and the facilitating moiety generates an oxidizing agent which channels to and reacts with the first member of the signal amplification pair:

(v) incubating the plurality of detectable captured truncated receptors with a second m em ber of the sign al amplifi cation pair to generate an amplified signal; and

[0161] In certain embodiments, the truncated receptor is p95HER2 and the full-length receptor is HE 2. In certain other embodiments, the plurality of beads specifi c for an extracellular domain (ECD) binding region comprises a streptavidin-biotin pair, wherein the biotin is attached to the bead and the biotin is attached to an antibody (e.g., wherein the antibody is specific for the ECD binding region of the full-length receptor).

[0162] In alternative embodiments, the first activation state-independent antibodies can be labeled with a first member of a signal amplification pair and the second activation state- independent antibodies can be labeled with a facilitating moiety.

[0163] The proximity assays described herein are typically antibody-based arrays which comprise one or a plurality of different capture antibodies at a range of capture antibody concentrations that are coupled to the surface of a solid support in different addressable locations. Examples of suitable solid supports for use in the present invention are described above.

[0164] The capture antibodies, activation state-independent antibodies, and activation state- dependent antibodies are preferably selected to minimize competition between them with respect to analyte binding (i. e., all antibodies can simultaneously bind their corresponding signal transduction molecules) ,

[0165] In some embodiments, activation state-independent antibodies for detecting activation levels of one or more of the analytes or, alternatively, first activation state- independent antibodies for detecting expression levels of one or more of the analytes further comprise a detectable moiety. In such instances, the amount of the detectable moiety is coiTelative to the amount of one or more of the analytes in the cellular extract. Examples of detectable moieties include, but are not limited to, fluorescent labels, chemically reactive labels, enzyme labels, radioactive labels, and the like. Preferably, the detectable moiety is a fluorophore such as an Alexa Fluor® dye (e.g., Alexa Fluor* 647), fluorescein, fluorescein isothiocyanate (FITC), Oregon Green™; rhodamine, Texas red, tetrarhodamine isothiocynate (TRITC), a CyDye™ fluor (e.g. , Cy2, Cy3, Cy5), and the like. The detectable moiety can be coupled directly or indirectly to the activation state-independent antibodies using methods well-known in the art. [0166] In certain instances, activation state -independent antibodies for detecting activation levels of one or more of the analytes or, alternatively, first activation state-independent antibodies for detecting expression levels of one or more of the analytes are directly labeled with the facilitating moiety. The facilitating moiety can be coupled to activation state - independent antibodies using methods well-known in the art. A suitable facilitating moiety for use in the present invention includes any molecule capable of generating an oxidizing agent which channels to (i.e., is directed to) and reacts with (i.e., binds, is bound by, or forms a complex with) another molecule in proximity (i.e., spatially near or close) to the facilitating moiety. Examples of facilitating moieties include, without limitation, enzymes such as glucose oxidase or any other enzyme that catalyzes an oxidation/reduction reaction involving molecular oxygen (O_?.) as the electron acceptor, and photosensitizers such as methylene blue, rose bengal, porphyrins, squarate dyes, phthalocyanines, and the like. Non-limiting examples of oxidizing agents include hydrogen peroxide (H₂O₂), a singlet oxygen, and any other compound that transfers oxygen atoms or gains electrons in an oxidation/reduction reaction. Preferably, in the presence of a suitable substrate (e.g., glucose, light, etc. ), the facilitating moiety (e.g., glucose oxidase, photosensitizer, etc. ) generates an oxidizing agent (e.g., hydrogen peroxide (H₂O₂), single oxygen, etc. ) which channels to and reacts with the first member of the signal amplification pair (e.g., horseradish peroxidase (HRP), hapten protected by a protecting group, an enzyme inactivated by thioether linkage to an enzyme inhibitor, etc.) when the two moieties are in proximity to each other. [0167] In certain other instances, activation state-independent antibodies for detecting activation levels of one or more of the analytes or, alternatively, first activation state- independent antibodies for detecting expression levels of one or more of the analytes are indirectly labeled with the facilitating moiety via hybridization between an oligonucleotide linker conjugated to the activation state-independent antibodies and a complementary oligonucleotide linker conjugated to the facilitating moiety. The oligonucleotide linkers can be coupled to the facilitating moiety or to the activation state -independent antibodies using methods well-known in the art. In some embodiments, the oligonucleotide linker conjugated to the facilitating moiety has 100% complementarity to the oligonucleotide linker conjugated to the activation state-independent antibodies. In other embodiments, the oligonucleotide linker pair comprises at least one, two, three, four, five, six, or more mismatch regions, e.g., upon hybridization under stringent hybridization conditions. One skilled in the art will appreciate that activation state-independent antibodies specific for different analytes can either be conjugated to the same oligonucleotide linker or to different oligonucleotide linkers. [0168] The length of the oligonucleotide linkers that are conjugated to the facilitating moiety or to the activation state-independent antibodies can vary. In general, the linker sequence can be at least about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, or 100 nucleotides in length. Typically, random nucleic acid sequences are generated for coupling. As a non- limiting example, a library of oligonucleotide linkers can be designed to have three distinct contiguous domains: a spacer domain; signature domain; and conjugation domain.

Preferably, the oligonucleotide linkers are designed for efficient coupling without destroying the function of the facilitating moiety or activation state -independent antibodies to which they are conjugated.

[0169] The oligonucleotide linker sequences can be designed to prevent or minimize any secondary structure formation under a variety of assay conditions. Melting temperatures are typically carefully monitored for each segment within the linker to allow their participation in the overall assay procedures. Generally, the range of melting temperatures of the segment of the linker sequence is between 1-10°C. Computer algorithms (e.g., OLIGO 6.0) for determining the melting temperature, secondary structure, and hairpin structure under defined ionic concentrations can be used to analyze each of the three different domains within each linker. The overall combined sequences can also be analyzed for their structural

characterization and their comparability to other conjugated oligonucleotide linker sequences, e.g., whether they will hybridize under stringent hybridization conditions to a complementary oligonucleotide linker. [0170] The spacer region of the oligonucleotide linker provides adequate separation of the conjugation domain from the oligonucleotide crosslinking site. The conjugation domain functions to link molecules labeled with a complementary oligonucleotide linker sequence to the conjugation domain via nucleic acid hybridization. The nucleic acid-mediated hybridization can be performed either before or after antibody-analyte (i.e., antigen) complex formation, providing a more flexible assay format. Unlike many direct antibody conjugation methods, linking relatively small oligonucleotides to antibodies or other molecules has minimal impact on the specific affinity of antibodies towards their target analyte or on the function of the conjugated molecules. [0171] In some embodiments, the signature sequence domain of the oligonucleotide linker can be used in complex multiplexed protein assays. Multiple antibodies can be conjugated with oligonucleotide linkers with different signature sequences. In multiplex immunoassays, reporter oligonucleotide sequences labeled with appropriate probes can be used to detect cross-reactivity between antibodies and their antigens in the multiplex assay format. [0172] Oligonucleotide linkers can be conjugated to antibodies or other molecules using several different methods. For example, oligonucleotide linkers can be synthesized with a thiol group on either the 5' or 3' end. The thiol group can be deprotected using reducing agents (e.g., TCEP-HCl) and the resulting linkers can be purified by using a desalting spin column. The resulting deprotected oligonucleotide linkers can be conjugated to the primary amines of antibodies or other types of proteins using heterobifunctional cross linkers such as SMCC. Alternatively, 5 '-phosphate groups on oligonucleotides can be treated with water- soluble carbodiimide EDC to form phosphate esters and subsequently coupled to amine- containing molecules. In certain instances, the diol on the 3'-ribose residue can be oxidized to aldehyde groups and then conjugated to the amine groups of antibodies or other types of proteins using reductive animation. In certain oilier instances, the oligonucleotide linker can be synthesized with a biotin modification on either the 3' or 5' end and conjugated to streptavi din-label ed molecules .

[0173] Oligonucleotide linkers can be synthesized using any of a variety of techniques known in the art, such as those described in Usman et al., J. Am. Chem. Soc, 109:7845 (1987); Scaringe ei al, Nucl. Acids Res., 18:5433 ( 1990); Wincott et al., Nucl. Acids Res., 23:2677-2684 (1995); and Wincott et al, Methods Mol. Bio. , 74:59 (1997). In general, the synthesis of oligonucleotides makes use of common nucleic acid protecting and coupling groups, such as dimethoxytrityl at the 5 '-end and phosphoramidites at the 3 '-end. Suitable reagents for oligonucleotide synthesis, methods for nucleic acid deprotection, and methods for nucleic add purification are known to those of skill in the art.

[0174] In certain instances, activation state-dependent antibodies for detecting activation levels of one or more of the analytes or, alternatively, second activation state-independent antibodies for detecting expression levels of one or more of the analytes are directly labeled with the first member of the signal amplification pair. The signal amplification pair member can be coupled to activation state-dependent antibodies to detect activation levels or second activation state-independent antibodies to detect expression levels using methods well-known in the art. In certain other instances, activation state-dependent antibodies or second activation state-independent antibodies are indirectly labeled with the first member of the signal amplification pair via binding between a first member of a binding pair conjugated to the activation state -dependent antibodies or second activation state-independent antibodies and a second member of the binding pair conjugated to the first member of the signal amplification pair. Tire binding pair members (e.g., biotin/streptavidin) can be coupled to the signal amplification pair member or to the activation state -dependent antibodies or second activation state-independent antibodies using methods well-known in the art. Examples of signal amplification pair members include, but are not limited to, peroxidases such horseradish peroxidase (HRP), catalase, chloroperoxida.se, cytochrome c peroxidase, eosinophil peroxidase, glutathione peroxidase, lactoperoxidase, myeloperoxidase, thyroid peroxidase, deiodinase, and the like. Other examples of signal amplification pair members include haptens protected by a protecting group and enzymes inactivated by thioether linkage to an enzyme inhibitor.

[0175] In one example of proximity channeling, the facilitating moiety is glucose oxidase (GO) and the first member of the signal amplification pair is horseradish peroxidase (HRP). When the GO is contacted with a substrate such as glucose, it generates an oxidizing agent (i.e., hydrogen peroxide ( \ i.O.>)). If the HRP is within channeling proximity to the GO, the H₂O₂ generated by the GO is channeled to and complexes with the HRP to form an HRP- H₂O₂ complex, which, in the presence of the second member of the signal amplification pair (e.g., a chemiluminescent substrate such as lummoi or isolummoi or a fluorogenic substrate such as tyramide (e.g., biotin-tyramide), homovanillic acid, or 4-hydroxyphenyl acetic acid), generates an amplified signal. Methods of using GO and HRP in a proximity assay are described in, e.g., Langry et a I. , U.S. Dept. of Energy Report No. UCRL-ID-136797 (1999). When biotin-tyramide is used as the second member of the signal amplification pair, the HRP-H₂O₂ complex oxidizes the tyramide to generate a reactive tyramide radical that covalently binds nearby nucleophilic residues, lire activated tyramide is either directly detected or detected upon the addition of a signal-detecting reagent such as, for example, a streptavidin-labeled fluorophore or a combination of a streptavidin-labeled peroxidase and a chromogenic reagent. Examples of fluorophores suitable for use in the present invention include, but are not limited to, an Alexa Fluor* dye (e.g., Alexa Fluor"⁵¹ 555), fluorescein, fluorescein isothiocyanate (FITC), Oregon Green™; rhodamine, Texas red, tetrarhodamine isothiocynate (TR1TC), a CyDye™ fluor (e.g., Cy2, Cy3, Cy5), and tlie like. The streptavidin label can be coupled directly or indirectly to the fluorophore or peroxidase using methods well-known in the art. Non-limiting examples of chromogenic reagents suitable for use in the present invention include 3,3',5,5'-tetramethylbenzidine (1MB), 3,3 '- diaminobenzidine (DAB), 2,2'~azino-bis(3-ethylbenzothiazo3ine-6~sulfonic acid) (ABTS), 4- chloro-l-napthol (4CN), and/or porphyrinogen.

[0176] In another example of proximity channeling, the facilitating moiety is a

photosensitizer and the first member of the signal amplification pair is a large molecule labeled with multiple haptens that are protected with protecting groups that prevent binding of tlie haptens to a specific binding partner (e.g., ligand, antibody, etc.). For example, the signal amplification pair member can be a dextran molecule labeled with protected biotin, coumarin, and/or fluorescein molecules. Suitable protecting groups include, but are not limited to, phenoxy-, analino-, olefin-, thioether-, and selenoether-protecting groups.

Additional photosensitizers and protected hapten molecules suitable for use in the proximity assays of the present invention are described in U.S. Patent No. 5,807,675. When the photosensitizer is excited with light, it generates an oxidizing agent (i.e., singlet oxygen). If the hapten molecules are within channeling proximity to the photosensitizer, tlie singlet oxygen generated by the photosensitizer is channeled to and reacts with thioethers on the protecting groups of the haptens to yield carbonyl groups (ketones or aldehydes) and sulphinic acid, releasing the protecting groups from the haptens. The unprotected haptens are then available to specifically bind to tlie second member of the signal amplification pair (e.g., a specific binding partner that can generate a detectable signal). For example, when the hapten is biotin, tlie specific binding partner can be an enzyme-labeled streptavidin.

Exemplary enzymes include alkaline phosphatase, β-gaiactosidase, HRP, etc. After washing to remove unbound reagents, the detectable signal can be generated by adding a detectable (e.g., fluorescent, chemiluminescent, chromogenic, etc.) substrate of the enzyme and detected using suitable methods and instrumentation known in the art. Alternatively, tlie detectable signal can be amplified using tyramide signal amplification and the activated tyramide either directly detected or detected upon the addition of a signal-detecting reagent as described above.

[0177] In yet another example of proximity channeling, the facilitating moiety is a photosensitizer and the first member of the signal amplification pair is an enzyme-inhibitor complex. The enzyme and inhibitor (e.g., phosphonic acid-labeled dextran) are linked together by a cleavable Sinker (e.g., thioether). When the photosensitizer is excited with light, it generates an oxidizing agent (i.e., singlet oxygen). If the enzyme-inhibitor complex is within channeling proximity to the photosensitizer, the singlet oxygen generated by the photosensitizer is channeled to and reacts with the cleavable linker, releasing the inhibitor from the enzyme, thereby activating the enzyme. An enzyme substrate is added to generate a detectable signal, or alternatively, an amplification reagent is added to generate an amplified signal.

[0178] In a further example of proximity channeling, the facilitating moiety is HRP, the first member of the signal amplification pair is a protected hapten or an enzyme-inhibitor complex as described above, and the protecting groups comprise p-alkoxy phenol. The addition of phenylenediamine and H₂O₂ generates a reactive phenylene diimine which channels to the protected hapten or the enzyme-inhibitor complex and reacts with p-alkoxy phenol protecting groups to yield exposed haptens or a reactive enzyme. The amplified signal is generated and detected as described above (see, e.g., U.S. Patent Nos. 5,532,138 and 5,445,944),

[0179] An exemplary protocol for performing the proximity assays described herein is provided in Example 4 of PCT Publication No. WO2009/108637, the disclosure of which is herein incorporated by reference in its entirety for all purposes.

[0180] In another embodiment, the present invention provides kits for performing the proximity assays described above comprising: (a) a dilution series of one or a plurality of capture antibodies restrained on a solid support; and (b) one or a plurality of detection antibodies (e.g., a combination of activation state-independent antibodies and activation state- dependent antibodies for detecting activation levels and/or a combination of first and second activation state -independent antibodies for detecting expression levels). In some instances, the kits can further contain instructions for methods of using the kit to detect the expression and/or activation status of one or a plurality of signal transduction molecules of cells such as tumor cells. The kits may also contain any of the additional reagents described above with respect to performing the specific methods of the present invention such as, for example, first and second members of the signal amplification pair, tyramide signal amplification reagents, substrates for the facilitating moiety, wash buffers, etc.

VI. Methods of Genotyping

[0181] A variety of means can be used to genotype an individual at a polymorphic site in an oncogene such as the KRAS, BRAF, PIK3CA, and/or EGFR gene to determine whether a sample (e.g. , a nucleic acid sample) contains a specific variant allele (e.g., somatic mutation) or haplotype. For example, enzymatic amplification of nucleic acid from an individual can be conveniently used to obtain nucleic acid for subsequent analysis. The presence or absence of a specific variant allele (e.g., somatic mutation) or haplotype in one or more oncogenes of interest can also be determined directly from the individual's nucleic acid without enzymatic amplification. In certain embodiments, an individual is genotyped at one, two, three, four, five, or more polymorphic sites such as a single nucleotide polymorphism (SNP) in one or more oncogenes of interest.

[0182] Genotyping of nucleic acid from an individual, whether amplified or not, can be performed using any of various techniques. Useful techniques include, without limitation, assays such as polymerase chain reaction (PGR) based analysis assays, sequence analysis assays, electrophoretic analysis assays, restriction length polymorphism analysis assays, hybridization analysis assays, allele-specific hybridization, oligonucleotide ligation allele- specific elongation/ligation, allele-specific amplification, single-base extension, molecular inversion probe, invasive cleavage, selective termination, restriction length polymorphism, sequencing, single strand conformation polymorphism (SSCP), single strand chain polymorphism, mismatch-cleaving, and denaturing gradient gel electrophoresis, all of which can be used alone or in combination. As used herein, the term "nucleic acid^'' includes a polynucleotide such as a single- or double -stranded DNA or RNA molecule including, for example, genomic DNA, cDNA and mRNA. This term encompasses nucleic acid molecules of both natural and synthetic origin as well as molecules of linear, circular, or branched configuration representing either the sense or antisense strand, or both, of a native nucleic acid molecule . It is understood that such nucleic acids can be unpunfied, purified, or attached, for example, to a synthetic material such as a bead or column matrix. [0183] In particular embodiments, the presence or absence of a variant allele (e.g.. somatic mutation) in one or more oncogenes of interest is determined using a genotyping assay as described in U.S. Provisional Application No. 61 /525, 137, filed August 18, 201 1 , and U.S. Provisional Application No, 61/588, 151, filed January 18, 2012, the disclosures of which are herein incorporated by reference in their entirety for all purposes.

[0184] Material containing nucleic acid is routinely obtained from individuals. Such material is any biological matter from which nucleic acid can be prepared. As non-limiting examples, material can be whole blood, serum, plasma, saliva, cheek swab, sputum, or other bodily fluid or tissue that contains nucleic acid. In one embodiment, a method of the present invention is practiced with whole blood, which can be obtained readily by non-invasive means and used to prepare genomic DNA. In another embodiment, genotyping involves amplification of an individual's nucleic acid using the polymerase chain reaction (PGR). Use of PGR for the amplification of nucleic acids is well known in the art (see, e.g., Muilis et al. (Eds.), The Polymerase Chain Reaction, Birkhauser, Boston, (1994)). In yet another embodiment, PGR amplification is performed using one or more fluorescently labeled primers. In a further embodiment, PGR amplification is performed using one or more labeled or unlabeled primers that contain a D A minor groove binder. [0185] Any of a variety of different primers can be used to amplify an individual's nucleic acid by PGR in order to determine the presence or absence of a variant allele (e.g., somatic mutation) in a method of the invention. As understood by one skilled in the art, primers for PGR analysis can be designed based on the sequence flanking the polymorphic site(s) of interest in the gene of interest. As a non-limiting example, a sequence primer can contain from about 15 to about 30 nucleotides of a sequence upstream or downstream of the polymorphic site of interest in the gene of interest. Such primers generally are designed to have sufficient guanine and cytosine content to attain a high melting temperature which allows for a stable annealing step in the amplification reaction. Several computer programs, such as Primer Select, are available to aid in the design of PGR primers. [0186] A Taqman^4y allelic discrimination assay available from Applied Biosystems can be useful for genotyping an individual at a polymorphic site to thereby determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest. In a Taqiuan^ allelic discrimination assay, a specific fluorescent dye-labeled probe for each allele is constructed. The probes contain different fluorescent reporter dyes such as FAM and VIC^{1 l} to differentiate amplification of each allele. In addition, each probe has a quencher dye at one end which quenches fluorescence by fluorescence resonance energy- transfer. During PGR, each probe anneals specifically to complementary sequences in the nucleic acid from the individual . The 5' nuclease activity of Taq polymerase is used to cleave only probe that hybridizes to the allele. Cleavage separates the reporter dye from the quencher dye, resulting in increased fluorescence by the reporter dye. Thus, the fluorescence signal generated by PCR. amplification indicates which alleles are present in the sample. Mismatches between a probe and allele reduce the efficiency of both probe hybridization and cleavage by Taq polymerase, resulting in little to no fluorescent signal. Those skilled in the art understand that improved specificit ⁷ in allelic discrimination assays can be achieved by conjugating a DNA minor groove binder (MGB) group to a DNA probe as described, e.g., in Kutyavin et ai, Nuc. Acids Research 28:655-661 (2000). Minor groove binders include, but are not limited to, compounds such as dihydrocyclopyrroloindole tripeptide (DPI3).

[0187] Sequence analysis can also be useful for genotyping an individual according to the methods described herein to determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest. As is known by those skilled in the art, a variant allele of interest can be detected by sequence analysis using the appropriate primers, which are designed based on the sequence fla king the polymorphic site of interest in the gene of interest. For example, a variant allele in a gene of interest can be detected by sequence analysis using primers designed by one of skill in the art. Additional or alternative sequence primers can contain from about 15 to about 30 nucleotides of a sequence that corresponds to a sequence about 40 to about 400 base pairs upstream or downstream of the polymorphic site of interest in the gene of interest. Such primers are generally designed to have sufficient guanine and cytosine content to attain a high melting temperature which allows for a stable annealing step in the sequencing reaction.

[0188] The term "sequence analysis" includes any manual or automated process by which the order of nucleotides in a nucleic acid is determined. As an example, sequence analysis can be used to determine the nucleotide sequence of a sample of DNA. The term sequence analysis encompasses, without limitation, chemical and enzymatic methods such as dideoxy enzymatic methods including, for example, Maxam-Gilbert and Sanger sequencing as well as variations thereof. The term sequence analysis further encompasses, but is not limited to, capillary array DNA sequencing, which relies on capillary electrophoresis and laser-induced fluorescence detection and can be performed using instruments such as the MegaBACE 1000 or AB1 3700. As additional non-limiting examples, the term sequence analysis encompasses thermal cycle sequencing (see, Sears et al, Biotechniqiies 13:626-633 (1992)); solid-phase sequencing (see, Zimmerman et al, Methods Mol. Cell Biol. 3:39-42 (1992); and sequencing with mass spectrometry, such as matrix-assisted laser de sorption/ionization time-of-flight mass spectrometry (see, MALDI-TOF MS; Fu et ai, Nature Biotech. 16:381-384 (1998)). Tire tenn sequence analysis further includes, but is not limited to, sequencing by hybridization (SBH), which relies on an array of ail possible short oligonucleotides to identify a segment of sequence (see, Chee et a!., Science 274:6 0-614 (1996); Drmanac et al, Science 260: 1649-1652 (1993); and Drmanac et al. Nature Biotech. 16:54-58 (1998)). One skilled in the art understands that these and additional variations are encompassed by the term. sequence analysis as defined herein,

[0189] Electrophoretic analysis also can be useful in genotyping an individual according to the methods of the present invention to determine the presence or absence of a particular variant allele {e.g., somatic mutation) or haplotype in the gene of interest. "Electrophoretic analysis" as used herein in reference to one or more nucleic acids such as amplified fragments includes a process whereby charged molecules are moved through a stationary medium under the influence of an electric field. Electrophoretic migration separates nucleic acids primarily on the basis of their charge, which is in proportion to their size, with smaller molecules migrating more quickly. The term electrophoretic analysis includes, without limitation, analysis using slab gel electrophoresis, such as agarose or polyacrylamide gel electrophoresis, or capillary electrophoresis. Capillary electrophoretic analysis generally occurs inside a small-diameter (50-100 m) quartz capillary in the presence of high (kilovolt- level) separating voltages with separation times of a few minutes. Using capillary electrophoretic analysis, nucleic acids are conveniently detected by UV absorption or fluorescent labeling, and single-base resolution can be obtained on fragments up to several hundred base pairs. Such methods of electrophoretic analysis, and variations thereof, are well known in the art, as described, for example, in Ausubel et al, Current Protocols in Molecular Biology Chapter 2 (Supplement 45) John Wiley & Sons, inc. New York (1999).

[0190] Restriction fragment length polymorphism (RFLP) analysis can also be useful for genotyping an individual according to the methods of the present invention to determine the presence or absence of a particular variant allele {e.g., somatic mutation) or haplotype in the gene of interest (see, Jarcho et al. in Dracopoli et al., Current Protocols in Human Genetics pages 2.7.1-2.7.5, John Wiley & Sons, New York; Innis et a!., (Ed.), PCR Protocols, San Diego: Academic Press, Inc. (1990)). As used herein, "restriction fragment length polymorphism analysis" includes any method for distinguishing polymorphic alleles using a restriction enzyme, which is an endonuclease that catalyzes degradation of nucleic acid following recognition of a specific base sequence, generally a palindrome or inverted repeat. One skilled in the art understands that the use of RFLP analysis depends upon an enzyme that can differentiate a variant allele from a wild-type or other allele at a polymorphic site. [0191] In addition, allele-specific oligonucleotide hybridization can be useful for genotyping an individual in the methods described herein to determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest. Allele-specific oligonucleotide hybridization is based on the use of a labeled oligonucleotide probe having a sequence perfectly complementar ', for example, to the sequence encompassing the variant allele. Under appropriate conditions, the variant allele- specific probe hybridizes to a nucleic acid containing the variant allele but does not hybridize to the one or more other alleles, which have one or more nucleotide mismatches as compared to the probe. If desired, a second allele-specific oligonucleotide probe that matches an alternate {e.g., wild-type) allele can also be used. Similarly, the technique of allele-specific oligonucleotide amplification can be used to selectively amplify, for example, a variant allele by using an allele-specific oligonucleotide primer that is perfectly complementary to the nucleotide sequence of the variant allele but which has one or more mismatches as compared to other alleles (Mullis et al, supra). One skilled in the art understands that the one or more nucleotide mismatches that distinguish between the variant allele and other alleles are often located in the center of an allele-specific oligonucleotide primer to be used in the allele- specific oligonucleotide hybridization. In contrast, an allele-specific oligonucleotide primer to be used in PCR amplification generally contains the one or more nucleotide mismatches that distinguish between the variant and other alleles at the 3' end of the primer, [0192] A heteroduplex mobility assay (HMA) is another well-known assay that can be used for genotyping in the methods of the present invention to determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest. HMA is useful for detecting the presence of a variant allele since a DNA duplex carrying a mismatch has reduced mobility in a polyacrylamide gel compared to the mobility of a perfectly base-paired duplex (see, Delwart et al, Science, 262: 257-1261 (1993); White et al, Genomics, 12:301-306 (1992)).

[0193] The technique of single strand conformational polymorphism (SSCP) can also be useful for genotyping in the methods described herein to determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest (see, Hayashi, Methods Applic, 1 :34-38 (1991)). This technique is used to detect variant alleles based on differences in the secondary structure of single-stranded DNA that produce an altered electrophoretic mobility upon non-denaturing gel electrophoresis. Variant alleles are detected by comparison of the electrophoretic partem of the test fragment to corresponding standard fragments containing known alleles. [0194] Denaturing gradient gel electrophoresis (DGGE) can also be useful in the methods of the invention to determine the presence or absence of a particular variant allele (e.g., somatic mutation) or haplotype in the gene of interest. In DGGE, double-stranded DNA is electrophoresed in a gel containing an increasing concentration of denaturant; double- stranded fragments made up of mismatched alleles have segments that melt more rapidly, causing such fragments to migrate differently as compared to perfectly complementary sequences (see, Sheffield et al, "Identifying DNA Polymorphisms by Denaturing Gradient Gel Electrophoresis" in Innis et al , supra, 1990).

[0195] Other molecular methods useful for genotypmg an individual are known in the art and useful in the methods of the present invention. Such well-known genotyping approaches include, without limitation, automated sequencing and Nase mismatch techniques (see. Winter et al, Proc. Natl. Acad. Sci. , 82:7575-7579 (1985)). Furthermore, one skilled in the art understands that, where the presence or absence of multiple variant alleles is to be determined, individual variant alleles can be detected by any combination of molecular methods. See, in general, Birren el al. (Eds.) Genome Analysis: A Laboratory Manual

Volume 1 (Analyzing DNA) New York, Cold Spring Harbor Laboratory Press (1997). In addition, one skilled in the art understands that multiple variant alleles can be detected in individual reactions or in a single reaction (a "multiplex" assay),

VII. Production of Antibodies

[0196] The generation and selection of antibodies not already commercially available for analy zing the levels of expression and activation of signal transduction molecules in tumor cells in accordance with the immunoassays of the present invention can be accomplished several ways. For example, one way is to express and/or purify a polypeptide of interest (i.e., antigen) using protein expression and purification methods known in the art, while another way is to synthesize the polypeptide of interest using solid phase peptide synthesis methods known in the art. See. e.g., Guide to Protein Purification, Murray P. Deutcher, ed., Meth. Enzymol, Vol. 182 (1990); Solid Phase Peptide Synthesis, Greg B. Fields, ed., Meth.

Enzymol., Vol. 289 (1997); Kiso et al, Chem. Pharm. Bull, 38: 1192-99 (1990); Mostafavi et al , Biomed. Pept. Proteins Nucleic Acids , 1 :255-60, (1995); and Fujrwara et al., Chem. Pharm. Bull., 44: 1326-31 (1996). The purified or synthesized polypeptide can then be injected, for example, into mice or rabbits, to generate polyclonal or monoclonal antibodies. One skilled in the art will recognize that many procedures are available for the production of antibodies, for example, as described in Antibodies. A Laboratory Manual, Harlow and Lane, Eds., Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y. (1988). One skilled in the art will also appreciate that binding fragments or Fab fragments which mimic (e.g., retain the functional binding regions of) antibodies can also be prepared from genetic information by various procedures. See, e.g., Antibody Engineering: A Practical Approach, Borrebaeck, Ed ,, Oxford University Press, Oxford (1995): and Huse et al., J. Immunol., 149:3914-3920 (1992),

[0197] Those skilled in the art will recognize that many approaches can be taken in producing antibodies or binding fragments and screening and selecting for affinity and specificity for the various polypeptides of interest, but these approaches do not change the scope of the present invention. [0198] A more detailed description of polyclonal antibodies, monoclonal antibodies, humanized antibodies, human antibodies, bispecific antibodies, fragments thereof, and methods of purifying antibodies is found in PCX Publication No. WO 2010/132723, the disclosure of which is herein incorporated by reference in its entirety for all purposes.

VIII. Methods of Administration

[0199] According to the methods of the present invention, the anticancer drugs described herein are administered to a subject by any convenient means known in the art. The methods of the present invention can be used to select a suitable anticancer drug or combination of anticancer drugs for the treatment of a tumor, e.g., a colorectal tumor, in a subject. The methods of the present invention can also be used to identify the response of a tumor, e.g., a colorectal tumor, in a subject to treatment with an anticancer drug or combination of anticancer drugs. In addition, the methods of the present invention can be used to predict the response of a subject having a tumor, e.g., a colorectal tumor, to treatment with a anticancer drag or combination of anticancer drags. One skilled in the art will appreciate that the anticancer drags described herein can be administered alone or as part of a combined therapeutic approach with conventional chemotherapy, radiotherapy, hormonal therapy, immunotherapy, and/or surgery.

[0200] In certain embodiments, the anticancer drug comprises an a ti -signaling agent (i.e., a cytostatic drug) such as a monoclonal antibody or a tyrosine kinase inhibitor: an antiproliferative agent; a chemotherapeutic agent (i.e., a cytotoxic drag): a hormonal therapeutic agent; a radiotherapeutic agent; a vaccine; and/or any other compound with the ability to reduce or abrogate the uncontrolled growth of aberrant cells such as cancerous cells. In some embodiments, the subject is treated with one or more anti-signaling agents, anti-proliferative agents, and/or hormonal therapeutic agents in combination with at least one chemotherapeutic agent. Exemplary monoclonal antibodies, tyrosine kinase inhibitors, anti-proliferative agents, chemotherapeutic agents, hormonal therapeutic agents, radiotherapeutic agents, and vaccines are described above.

[0201] In some embodiments, the anticancer drugs described herein can be co-administered with conventional immunotherapeutic agents including, but not limited to, immunostimulants (e.g., Bacillus Calmette-Guerin (BCG), levamisole, interleukin-2, alpha-interferon, etc.), immunotoxins (e.g., anti-CD33 monoclonal antibody -calicheamicin conjugate, anti-CD22 monoclonal antibody-pseudomonas exotoxin conjugate, etc. ), and radioimmunotherapy (e.g., anti-CD20 monoclonal antibody conjugated to ^{U 1}ln, ⁹⁰Y, or ¹³ T, etc.). [0202] Anticancer drugs can be administered with a suitable pharmaceutical excipient as necessary and can be carried out via any of the accepted modes of administration. Thus, administration can be, for example, oral, buccal, sublingual, gingival, palatal, intravenous, topical, subcutaneous, transcutaneous, transdermal, intramuscular, intra-joint, parenteral, intra-arteriole, intradermal, intraventricular, intracranial, intraperitoneal, intravesical, intrathecal, intralesionai, intranasal, rectal, vaginal, or by inhalation. By "co-administer" it is meant that an anticancer drug is administered at the same time, just prior to, or just after the administration of a second drug (e.g., another anticancer drug, a drug useful for reducing the side-effects associated with anticancer drag therapy, a radiotherapeutic agent, a hormonal therapeutic agent, an immunotherapeutic agent, etc.). [0203] A therapeutically effective amount of an anticancer drug may be administered repeatedly, e.g. , at least 2, 3, 4, 5, 6, 7, 8, or more times, or the dose may be administered by continuous infusion. The dose may take the form of solid, semi-solid, lyophilized powder, or liquid dosage forms, such as, for example, tablets, pills, pellets, capsules, powders, solutions, suspensions, emulsions, suppositories, retention enemas, creams, ointments, lotions, gels, aerosols, foams, or the like, preferably in unit dosage fonns suitable for simple administration of precise dosages.

[0204] As used herein, the term "unit dosage form" refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of an anticancer drug calculated to produce the desired onset, tolerability, and/or therapeutic effects, in association with a suitable pharmaceut ical excipient (e.g., an ampoule). In addition, more concentrated dosage fonns may be prepared, from which the more dilute unit dosage forms may then be produced. The more concentrated dosage forms thus will contain substantially more than, e.g., at least 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, or more times the amount of the anticancer drug.

[0205] Methods for preparing such dosage forms are known to those skilled in the art (see, e.g. , REMINGTON'S PHARMACEUTICAL SCIENCES, 18TH ED., Mack Publishing Co., Easton, PA (1990)). The dosage forms typically include a conventional pharmaceutical carrier or excipient and may additionally include other medicinal agents, carriers, adjuvants, diluents, tissue permeation enhancers, solubilizers, and the like. Appropriate excipients can be tailored to the particular dosage form and route of administration by methods well known in the art

(see, e.g., REMINGTON 'S PHARMACEUTICAL SCIENCES, supra).

[0206] Examples of suitable excipients include, but are not limited to, lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcry stall ine cellulose, polyvinylpyrrolidone, cellulose, water, saline, syrup, methylcellulose, ethylceiluiose, hydroxypropylmethylceiluiose, and polyacrylic acids such as Carbopols, e.g. , Carbopol 941, Carbopol 980, Carbopol 981 , etc. The dosage forms can additionally include lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying agents; suspending agents; preserving agents such as methyl-, ethyl-, and propyl -hydroxy-benzoates (i.e., the parabens); pH adjusting agents such as inorganic and organic acids and bases; sweetening agents; and flavoring agents. The dosage forms may also comprise biodegradable polymer beads, dextran, and cyclodextrin inclusion complexes.

[0207] For oral administration, the therapeutically effective dose can be in the form of tablets, capsules, emulsions, suspensions, solutions, syrups, sprays, lozenges, powders, and sustained-release formulations. Suitable excipients for oral administration include pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, talcum, cellulose, glucose, gelatin, sucrose, magnesium carbonate, and the like.

[0208] In some embodiments, the therapeutically effective dose takes the form of a pill, tablet, or capsule, and thus, the dosage form, can contain, along with an anticancer drug, any of the following: a diluent such as lactose, sucrose, dicalcium phosphate, and the like; a disintegrant such as starch or derivatives thereof; a lubricant such as magnesium stearate and the like; and a binder such a starch, gum acacia, polyvinylpyrrolidone, gelatin, cellulose and derivatives thereof. An anticancer drug can also be formulated into a suppository disposed, for example, in a polyethylene glycol (PEG) carrier. [0209] Liquid dosage forms can be prepared by dissolving or dispersing an anticancer drug and optionally one or more pharmaceutically acceptable adjuvants in a carrier such as, for example, aqueous saime (e.g., 0.9% w/v sodium chloride), aqueous dextrose, glycerol, ethanol, and the like, to form a solution or suspension, e.g., for oral, topical, or intravenous administration. An anticancer drug can also be formulated into a retention enema.

[0210] For topical administration, the the apeutically effective dose can be in the form of emulsions, lotions, gels, foams, creams, jellies, solutions, suspensions, ointments, and transdermal patches. For administration by inhalation, an anticancer drug can be delivered as a dry powder or in liquid form via a nebulizer. For parenteral administration, the therapeutically effective dose can be in the form of sterile injectable solutions and sterile packaged powders. Preferably, injectable solutions are formulated at a pH of from about 4.5 to about 7.5.

[0211] The therapeutically effective dose can also be provided in a lyophilized form. Such dosage forms may include a buffer, e.g., bicarbonate, for reconstitution prior to

administration, or the buffer may be included in the lyophilized dosage form for

reconstitution with, e.g., water. The lyophilized dosage form may further comprise a suitable vasoconstrictor, e.g., epinephrine. The lyophilized dosage form can be provided in a syringe, optionally packaged in combination with the buffer for reconstitution, such that the reconstituted dosage form can be immediately administered to a subject. [0212] A subject can also be monitored at periodic time intervals to assess the efficacy of a certain therapeutic regimen. For example, the activation states of certain signal transduction molecules may change based on the therapeutic effect of treatment with one or more of the anticancer drugs described herein. The subject can be monitored to assess response and understand the effects of certain drugs or treatments in an individualized approach.

Additionally, subjects who initially respond to a specific anticancer drug or combination of anticancer drugs may become refractory to the dmg or drug combination, indicating that these subjects have developed acquired drug resistance. These subjects can be discontinued on their current therapy and an alternative treatment prescribed in accordance with the methods of the present invention. [0213] In certain aspects, the methods described herein can be used in conjunction with panels of gene expression markers that predict the likelihood of colorectal cancer prognosis and/or recurrence in various populations. These gene panels can be useful for identifying individuals who are unlikely to experience recurrence and, thus, unlikely to benefit from adjuvant chemotherapy. The expression panels can be used to identify individuals who can safely avoid adjuvant chemotherapy, without negatively affecting disease-free and overall survival outcomes. Suitable systems include, but are not limited to, Oncotype DX™, which is a 21 -gene panel from Genomic Health, Inc.; MammaPrint,* which is a 70-gene panel from Agendia; and a 76-gene parse! from Veridex.

[0214] In addition, in certain other aspects, the methods described herein can be used in conjunction with panels of gene expression markers that identify the original tumors for cancers of unknown primary (CUP). These gene panels can be useful in identifying patients with metastatic cancer who would benefit from therapy consistent with that given to patients diagnosed initially with colorectal cancer. Suitable systems include, but are not limited to, the Aviara CancerTYPE ID assay, an RT-PCR-based expression assay that measures 92 genes to identify the primary site of origin for 39 tumor types; and the Pathwork^®1 Tissue of Origin Test, which measures the expression of m ore than 1600 genes on a microarray and compares a tumor's gene expression "signature" against those of 15 known tissue types. IX. Examples

[0215] Hie following examples are offered to illustrate, but not to limit, the claimed invention.

Example 1. A Comprehensive Profiling of Colorectal Cancer Patients Via Multiplexed Functional Pathway Signature and Somatic Mutation Analysis. Background:

[0216] Colorectal cancer (CRC) is a leading cause of death in the developed nations. The development of effective forms of cytotoxic chemotherapy for colorectal cancer has been paralleled by the emergence of monoclonal antibodies against proteins that are thought to be important in the proliferation of malignant cells. Recent clinical studies showed that EGFR- targeting agents improved response rate when added to chemotherapy; however, patients with KRAS mutations did not benefit from such treatment. The study provided in this example demonstrates a comprehensive profiling of ErbB proteins as well as ErbB associated signal proteins for their level of expression/activation and the presence of somatic mutations in tumor tissues obtained from 136 CRC patients. Methods:

[0217] The Collaborative Enzyme Enhanced Reactive-immunoassay (CEER) is a multiplexed protein microarray platform, requiring co-localization of two detector enzyme- conjugated-antibodies. Once target proteins are captured on the microarray-surface, channeling events between two detector enzymes in proximity enable the profiling of the target proteins with high sensitivity. In this study, tumor h safes were prepared from frozen tissues obtained from 136 CRC patients. In addition to a multiplexed analysis for a panel of mutations in KRAS and BRAF genes, the level of expression and activation of HERI , HER2, HERS, cMET, cKIT, TGF-1R, PI3K, AKT, ERK and other pathway proteins were determined using the CEER technology.

Results:

[0218] Figure 1 provides tables which show that KRAS and BRAF mutations were found in -40% (54/136) and -5% (6/136), respectively, in this cohort. The most frequent mutant alleles were G12D (14%) and G13D (13%). Figure 2 provides a table showing that varying levels of RTKs and associated activation patterns were observed. Levels of phosphorylated AKT and ERK correlated to expression/activation patterns of HERI, cMET, HER3 and the prevalence of each biomarker can be determined.

Conclusion:

10219] A comprehensive profiling based on multiplexed functional pathway/somatic mutation analysis provides critical information clinicians need to select the most effective targeted agents for combination or sequenced treatments.

Example 2. Combination Analysis of Oncogenic Mutation and Signaling Pathway Profile Markers in Primary and Metastatic Colorectal Cancers, [0220] Despite overall improvements in colorectal cancer (CRC) therapies, an

understanding of reasons for therapeutic response/non-response as well as disease recurrence remains poor. Currently, the gold standard for CRC prognosis remains the

clmicopathological staging of tumors. Addition of molecular markers for predicting prognosis and therapeutic outcomes can significantly enhance the clinical managements of CRCs.

[0221] A comprehensive molecular characterization of 1 16 stage I to IV Asian CRC patients that also included 2 paired normal samples and 19 hepatic metastases of which 10 were from paired primary tumor samples (total 136 specimens) was performed. Somatic mutational analysis scored for 12 different mutations resident within the KRAS. BRAF and PIK3CA oncogenes alongside a parallel determination of kinase activation profiles for HERI, HER2, HER3, c-MET, IGF1R, PI3K, She, AKT and ERK using the multiplexed

Collaborative Enzyme Enhanced Reactive (CEER) immunoassay . CEER is a highly sensitive and specific proximity assay that relies on the formation of a triple antibody complex surrounding the target protein. Various mutations of KRAS and BRAF were found in 41% (48/1 16) and 4% (5/1 16) of patients, respectively. Incidence of PIK3CA mutations were 11% (13/116) in this cohort. Overall, KIMS G12D and G13D mutations were the most frequent in this cohort. Several primary as well as metastatic CRCs with KRAS mutations demonstrated a second mutation in the PIK3CA gene. While both ErbB-driven and non-ErbB-driven pathway signatures were observed in this cohort, there was no apparent correlation found between the KRAS mutational status of the tumors and the activation status of the downstream/upstream pathway signals.

[0222] Molecular characterization of CRC samples revealed distribution and frequency of specific oncogenic mutations in primary and metastatic colorectal cancers. As their influence on signaling pathway profiles cannot be predicted based on mutations alone, it is critical to also evaluate pathway activation for a more effective clinical strategy. This study also demonstrated modulation in signaling pathways concomitant with disease recurrence. Such clinical validations and comprehensive molecular profiles of CRC tumors can allow for the implementation of these companion biomarkers in CRC therapeutic clinical trials.

Example 3. Data Analysis for Quantitation of Signal Transduction Pathway Proteins in Cancer Cells.

[0223] This example illustrates the quantitation of the expression and/or activation levels of one or more analytes such as one or more signal transduction proteins in a biological sample (e.g., CTC or FNA) against a standard curve generated for the particular anaiyte of interest.

[0224] In some embodiments, each CEER. slide is scanned at three photomultiplier (PMT) gain settings to improve sensitivity and reduce the impact of saturation. Perkin Elmer ScanArray Express software is used for spot finding and signal quantitation. The identifiers for each spot are imported from a GenePix Array List (.gal) file. The de-identified study specific number for each clinical sample on a slide is incorporated into the resulting data set.

[0225] In other embodiments, background corrected signal intensities are averaged for replicate spots printed in triplicate. The relative fluorescence value of the respective reagent blank is subtracted from each sample. Several quality criteria are used to filter data from further analysis including limits on the spot footprint, coefficient of variation for spot replicates, overall pad background and the intensity of the reagent blank.

[0226] For each assay, a sigmoidal standard curve can be generated from multiple (e.g., two, three, four, five, six, seven, etc.) concentrations of serially diluted cell lysates prepared from, cell Sines such as MD-468 (HER1 positive), SKBr3 (HER2 positive), BT474 (HER2 and p95HER2 positive), HCC827 (c-MET and HER ! positive), T47D stimulated with IGF (1GF1R positive), and/or T47D stimulated with HRG (HER3 positive). Each curve can be plotted as a function of signal intensity vs. log concentration derived units, CU (Computed Unit). The data, can be fit to a five parameter equation (5PL) by nonlinear regression (Ritz, C. and Streibig, J. C., J. Statistical Software, 12, 1 -22 (2005)), simultaneously fitting all three dilutions of the capture antibody. Fitting is carried out using R, an open source statistical software package (Development Core Team, R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL. htt : //ww w . R-pr o j e ct . o rg . R (2008)). To avoid over parameterization of the mathematical model and thereby improve accuracy, four parameters can be constrained, while each dilution can be solved for an individual inflection point. This process can be repeated for each PMT gain setting of 45, 50 and 60. This results in nine standard curves generated per assay, from three dilutions of capture antibody and three PMT scans. The built-in redundancy in the assay allows for one or more of the dilution/scan combinations to be eliminated if the fit of the standard curve has an R² less than 0.95 and thus improves subsequent predictions.

[0227] CU Calculation (based on standard curve) - The individual predictions from each of the standard curves (e.g., 3 capture antibody dilutions and 3 PMT gain-set scanning) can be combined into a single, final prediction. For each prediction, the slope of the point on the standard curve is calculated. This slope is taken with log-units on the x-axis, i.e., the units in the denominator of the slope are log Computed Units (CU). Second, a weighted average of the predictions is calculated, where the weights are determined from the slopes. Specifically, the weights are summed, and each point is given a weight equal to its slope divided by the total slopes. Each assay can be validated against predictions for known controls.

Example 4. Pathway Redundancy and Feedback Loop May Be the Major Driver of Non-Response in Colorectal Cancer Treatments.

[0228] Background: Despite overall improvements in colorectal cancer (CRC) therapies, an understanding of therapeutic response as well as disease recurrence remains poor.

Currently, the gold standard for CRC prognosis remains the clinicopathological staging of tumors. There is urgent need for rational therapy selection based on functional -path way characterization to achieve significantly improved clinical outcome. [0229] Methods: 207 CRC patients (or 256 samples with matching metastatic tumor tissues in some patients) were evaluated for >100 signal transduction proteins. Receptor tyrosine kinases (RTKs, e.g., ErbBs, FGFRs, VEGFRs, cMET, IGFIR, etc.) and non-RTKs (e.g., Src, FAK, etc.) as well as Jak/Stat along with AKT and MAPK pathway proteins were analyzed for their level of expression and activation utilizing the Collaborative Enzyme Enhanced Reactive (CEER) immunoassay. In addition to pathway profiling, samples were also molecularly characterized for 14 different mutations within the KRAS, BRAF and PIK3CA oncogenes.

[0230] Results: Both ErbB/VEGFR driven and ErbB/VEGFR-independent signal transduction activation patterns were observed in the CRC patients with complex redundant pathway circuitry. Phosphorylated RTKs led to downstream AKT and MAPK pathway activation. Various mutations in KRAS, PIK3CA and BRAF were found in 42%, 11% and 4% of CRC patients, respectively. KRAS G12D and G13D mutations were the most frequent mutations. The % of mutant alleles increased in matching metastatic tumors when compared to the primary tumors. While downstream signal transduction via AKT and MAPK pathways were similar in both w ild-type and mutant tumors, higher le v els of potential compensating non-ErbB driven RTK expression/activation were obsen'ed in KRAS mutant patients. Figure 3 shows that the expression levels of cMET and IGF IR were significantly higher in KRAS mutant patients than in KRAS wild-type (WT) patients (p ^:= 0.001 ). Figure 4 show s that the activation (i.e., phosphorylation) level of cMET was significantly higher in KRAS mutant patients than in KRAS WT patients (p = 0.09). A significant pathway redundancy was detected in most tumors. Furthermore, pathway diversity in tumors with identical mutational background was evident in this analysis. Redundant pathways leading to distinct pathway activation patterns were also determined among the paired primary-metastatic samples. [0231] Conclusions: CEER-based pathway analysis adds value towards an understanding of a CRC tumor's potential response under various clinical scenarios. The comprehensive characterization of pathway redundancy allows the rational selection of a combination of targeted agents. Based on pathway circuitry determined by CEER, clinicians can make rational decisions in selecting agents targeting relevant pathway proteins. [0232] All publications and patent applications cited in this specification are herein incorporated by reference as if each indi vidual publication or patent application were specifically and individually indicated to be incorporated by reference. Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications m ay he made thereto without departing from the spirit or scope of the appended claims.

Claims

WHAT IS CLAIMED IS: 1. A method for determining whether an anticancer drug targeting one or more non-ErbB receptor tyrosine kinases (RTKs) should be administered for the treatment of colorectal cancer in a subject with a KRAS mutation, the method comprising:

(a) detecting the expression level and/or activation level of one or more non- ErbB RTKs in a cancer cell obtained from the subject; and (b) determining that an anticancer drag targeting one or more non-ErbB RTKs should be administered to the subject when a higher expression level or activation level of one or more non-ErbB RTKs is detected compared to the expression level or activation level of the same non-ErbB RTKs in a cancer cell from a KRAS wild-type subject.

2. The method of claim 1, wherein the one or more non-ErbB RTKs is selected from the group consisting of cMET, IGFIR, FGFRs, VEGF s, and combinations thereof.

3. The method of claim 2, wherein the expression level of cMET and/or IGFIR is higher in the cancer cell obtained from the subject compared to the cancer cell from the KRAS ^' wild-type subject.

4. The method of claim 2 or 3, wherein the activation level of cMET is higher in the cancer cell obtained from the subject compared to the cancer cell obtained from the KR iS wild-type subject.

5. The method of any one of claims I to 4, wherein the KRAS mutation is selected from the group consisting of G12S, G12D, G12A, G12V, G12R, G12C, GOD, and combinations thereof.

6. The method of any one of claims 1 to 5, wherein the cancer cell is a circulating tumor cell (CTC) or a fine needle aspirate (FNA) cell obtained from a colorectal tumor.

7. The method of claim 6, wherein the tumor is primary tumor tissue or metastatic tumor tissue.

8. The method of any one of claims I to 7, further comprising detecting the expression level and/or activation level of one or more ErbB RTKs, 9 The method of claim 8, wherein the expression level and/or activation level of the one or more ErbB RTKs is higher in the cancer cell obtained from the subject as compared to a reference expression level and/or activation level of the same ErbB RTKs. 10. The method of claim 9, further comprising determining that an anticancer drug targeting one or more ErbB RTKs should be administered to the subject. 11. The method of any one of claims 8 to 10, wherein the one or more ErbB RTKs is selected from the group consisting of HER1, HER2, HER3, HER4, and combinations thereof. 12. The method of any one of claims 1 to 11, wherein the anticancer drug is selected from the group consistmg of a monoclonal antibody, a tyrosine kinase mhibitor, an anti-proliferative agent, a chemotlierapeutic agent, and combinations thereof.