MET amplification identified by next-generation sequencing and its clinical relevance for MET inhibitors

BackgroundMETamplification plays an important role in the development of non-small-cell lung cancer (NSCLC) either de novo or in resistance to epidermal growth factor receptor tyrosine–kinase inhibitor (EGFR-TKI) settings. Fluorescence in situ hybridization (FISH) is the standard method forMETamplification. With more and more discoveries of oncogenic driver genes, next-generation sequencing (NGS) plays a significant role in precision oncology. Meanwhile, the role of NGS inMETamplification remains uncertain.MethodsForty patients diagnosed with advanced NSCLC were included. FISH and NGS were conducted prior to MET inhibitors treatment.METamplification by FISH was defined as a MET/CEP7 ratio of > 2.0 and/or copy number (CN) > 5.METamplification by NGS was defined as gene copy number (GCN) ≥ 5.ResultsThe concordance rate among FISH and NGS was 62.5% (25/40).METamplification identified by FISH showed the optimal predictive value. The partial response (PR) rate was 68.0% (17/25 withMETamplification) vs. 6.7% (1/15 withoutMETamplification); the median progression-free survival (PFS) was 5.4 months versus 1.0 months (P METamplification identified by NGS failed to distinguish significant clinical outcomes. The PR rate was 60.0% (6/10, withMETGCN ≥ 5) vs. 40.0% (12/30, withMETGCN ConclusionsMETamplification identified by FISH remains the optimal biomarker to identify suitable candidates for MET-TKI therapy. In comparison, amplification identified by NGS seems not as robust to be effective predictive biomarker. Further exploration is needed regarding the focal amplification by NGS in predicting the efficacy.