Frequency of MET amplification determined by comprehensive next-generation sequencing (NGS) in multiple solid tumors and implications for use of MET inhibitors.

Abstract

11068 Background: MET expression has been shown to be prognostic and possibly predictive in several tumor types and both small molecule inhibitors of MET kinase as well as monoclonal antibodies are under study as therapies for this subset of patients. However, the methods to assess MET overexpression are not well standardized. In the clinic, NGS is an advanced diagnostic method for identifying known and unknown targeted-therapy options. We therefore sought to explore the ability of NGS to detect high level MET amplifications in a general oncology population. Methods: We review here the results from analysis of 2,221 FFPE tissue samples across a range of tumor types by an NGS assay in a CLIA-certified laboratory (Foundation Medicine). We specifically report base pair substitutions, small insertions/homozygous deletions (indels), high level (> 6 copies/nucleus) amplification (amp) and select rearrangements in 189 genes, including MET. Results: MET was altered in 28/2,223 (1.2%) of patient samples. MET alterations were limited to amplifications (median 15X, range 6X-40X); no base pair substitutions, indels, or rearrangements were found. MET amp was present in 3/48 (6.2%) primary bone sarcomas, 1/20 (5.0%) myogenic sarcomas, 2/58 (3.4%) gastric, 1/38 (2.6%) kidney, 2/78 (2.5%) hepatocellular, 1/41 (2.4%) uterine, 4/188 (2.1%) unknown primary, 2/99 (2.0%) ovarian, 8/386 (2.0%) lung, 3/157 (1.9%) colorectal, and 1/109 (0.9%) pancreatic carcinomas. Conclusions: Use of NGS to characterize MET alterations in a 2,000+ patient population provides evidence for the role of NGS in identifying the future use of MET-targeted therapy in a variety of common and uncommon solid tumors. Clinical follow-up of the subset of cases treated with a MET inhibitor is ongoing.