Multiple independent methods fail to confirm MET amplification rate reported in literature for metastatic colorectal cancer (mCRC).

572 Background: MET inhibition is emerging as a potent therapeutic strategy and MET gene amplification has shown predictive significance. MET amplification rate in mCRC, as previously reported in literature, varies from 9% in primary to 18% in metastases but intermixes increased copy number from chromosomal level aberrations with focal gene amplification. Validation of MET amplification rate in mCRC is needed. Methods: We performed analyses of MET amplification in mCRC patients (pts) (n = 636) across multiple cohorts. Cohort 1 (n = 103) included tissue microarray from liver metastases analysed using fluorescence in situ hybridization (FISH) [cMET and CEP7 probes, MET/CEP7 ratio > 2]. Cohort 2 (n = 205) included pts referred for phase I trials who had MET amplification testing using FISH. Cohort 3 (n = 279) included cases sequenced with HiSeq (Illumina) with full exome coverage for 202 genes including MET (average depth 800) with focal gene amplification (≥ 4 copies) identified by an in-house algorithm. Co...