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Dysregulated MET signaling plays an important role in lung oncogenesis, tumor growth and invasiveness. It may occur through various mechanisms, such as MET overexpression or gene amplification or mutation, all of which can be detected by specific methods. The utility of MET overexpression as a biomarker remains unclear due to discrepancies in its occurrence and non-standardized cut-off thresholds. MET exon 14 skipping mutation (METex14) was established as a strong predictor of response to selective MET tyrosine kinase inhibitors (TKIs), and clinical trial results in patients with non-small cell lung cancer (NSCLC) harboring METex14 led to the approval of capmatinib and tepotinib by regulatory agencies worldwide. MET amplification is an emerging biomarker, with clinical data indicating an association between MET gene copy number and response to MET-TKIs. Additionally, MET amplification represents an important mechanism of resistance to TKIs in oncogene-driven NSCLC. The identification of molecular alterations for which targeted therapies are available is important, and high-throughput next-generation sequencing techniques can provide information on multiple genes at the same time, helping to provide valuable predictive information for oncogene-driven cancers. This review summarizes the current methods used for the detection of METex14, MET amplification and MET overexpression, and discusses the evidence for the use of MET-TKIs in patients with NSCLC with MET dysregulation. We discuss the practical challenges that impact the use of METex14 in the clinic and the evidence gaps that need to be addressed to validate additional genomic markers for MET-dependent cancers., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Gillianne GY Lai reports receiving honoraria from Amgen and grants from Merck, Astra Zeneca, Pfizer, Bristol Myers Squibb and Roche outside the submitted work. Robin Guo reports receiving honoraria from Pfizer outside the submitted work. Alexander Drilon reports receiving advisory board honoraria from Ignyta/Genentech/Roche, Loxo/Bayer/Lilly, Takeda/Ariad/Millennium, TP Therapeutics, AstraZeneca, Pfizer, Blueprint Medicines, Helsinn, Beigene, BergenBio, Hengrui Therapeutics, Exelixis, Tyra Biosciences, Verastem, MORE Health, Abbvie, 14ner/Elevation Oncology, ArcherDX, Monopteros, Novartis, EMD Serono, Medendi, Repare RX, Nuvalent, Merus, Chugai Pharmaceutical, Remedica Ltd , mBrace, AXIS, EPG Health, Harborside Nexus, Liberum, RV More, Ology, Amgen, TouchIME, Janssen, Entos, Treeline Bio, Prelude, Applied Pharmaceutical Science, Inc, AiCME, i3 Health, MonteRosa; equity from Treeline Bio; grants from Pfizer, Exelixis, GlaxoSmithKline, Teva, Taiho, PharmaMar; Royalties from Wolters Kluwer; CME honoraria from Medscape, OncLive, PeerVoice, Physicians Education Resources, Targeted Oncology, Research to Practice, Axis, Peerview Institute, Paradigm Medical Communications, WebMD, MJH Life Sciences, Med Learning, Imedex, Answers in CME, Clinical Care Options, EPG Health, JNCC/Harborside, Liberum, Remedica Ltd; and other financial/non-financial interests in Merck, Puma, Merus, Boehringer Ingelheim outside the submitted work. Dr. Drilon and Dr. Guo were supported in part by the National Cancer Institute of the National Institutes of Health P30 CA008748. Daniel S.W. Tan reports receiving honoraria from Takeda Pharmaceuticals, Novartis, Roche, Pfizer, Merck and Boehringer Ingelheim; consulting fees from Novartis, Bayer, Boehringer Ingelheim, Astra-Zeneca, Eli-Lilly, MSD, GlaxoSmithKline, LOXO as well as grants from Amgen, Novartis, GlaxoSmithKline, AstraZeneca and Pfizer outside the submitted work., (Copyright © 2022. Published by Elsevier Ltd.)

Objectives: Single-agent heat shock protein 90 (HSP90) inhibition has demonstrated activity in oncogene-driven non-small cell and small cell lung cancers. SNX-5422 is an oral HSP90 inhibitor with increased activity in vitro with the addition of carboplatin and paclitaxel. Therefore, we conducted a phase 1, open-label, multicenter study to evaluate SNX-5422, carboplatin and paclitaxel followed by SNX-5422 maintenance in patients with advanced lung cancers., Materials and Methods: In part 1 (3 + 3 dose escalation), SNX-5422 (50/75/100-mg/m 2 ) was dosed every other day (qod) for 21 days (28-day cycle) for ≤4 cycles; carboplatin (AUC 5)-paclitaxel (175 mg/m 2 ) was administered once every 3 weeks for ≤6 courses. In part 2 (maintenance), subjects who achieved at least stable disease in part 1 received 100 mg/m 2 SNX-5422 monotherapy qod for 21 days (28-day cycle)., Results: Twenty-three patients with advanced non-small cell lung cancer (NSCLC, n = 20) and small cell lung cancer (SCLC, n = 3) were enrolled. The median age was 60 years and 61% (n = 14/23) had ≥1 prior treatment regimens. The maximum tolerated dose of SNX-5422 was 100 mg/m 2 qod in combination with carboplatin-paclitaxel. The most common treatment-related grade 3/4 adverse events (part 1/part 2) were diarrhea (26%/15%) and nausea (9%/0%). In response-evaluable patients with NSCLC, 33% (6/18) had a partial response, 56% (10/18) stable disease, and 11% (2/18) progressive disease. Patients who remained on single-agent SNX-5422 maintenance therapy ≥2 months (n = 9) had cancers enriched for oncogenic drivers (n = 3 KRAS mutation, n = 1 EGFR exon 20 mutation, n = 1 HER2 mutation, and n = 1 RET fusion)., Conclusions: The triplet combination of SNX-5422, carboplatin and paclitaxel followed by maintenance SNX-5422 therapy was well-tolerated and showed anti-tumor activity. Cancers for which disease control on single-agent SNX-5422 maintenance was observed were enriched for oncogene-driven NSCLCs., (Copyright © 2021. Published by Elsevier B.V.)

Purpose: MET tyrosine kinase inhibitors (TKIs) can achieve modest clinical outcomes in MET exon 14-altered lung cancers, likely secondary to primary resistance. Mechanisms of primary resistance remain poorly characterized and comprehensive proteomic analyses have not previously been performed., Experimental Design: We performed hybrid capture-based DNA sequencing, targeted RNA sequencing, cell-free DNA sequencing, selected reaction monitoring mass spectrometry (SRM-MS), and immunohistochemistry on patient samples of MET exon 14-altered lung cancers treated with a MET TKI. Associations between overall response rate (ORR), progression-free survival (PFS), and putative genomic alterations and MET protein expression were evaluated., Results: Seventy-five of 168 MET exon 14-altered lung cancers received a MET TKI. Previously undescribed (zygosity, clonality, whole-genome duplication) and known (copy-number focality, tumor mutational burden, mutation region/type) genomic factors were not associated with ORR/PFS ( P > 0.05). In contrast, MET expression was associated with MET TKI benefit. Only cases with detectable MET expression by SRM-MS ( N = 15) or immunochemistry ( N = 22) responded to MET TKI therapy, and cancers with H-score ≥ 200 had a higher PFS than cancers below this cutoff (10.4 vs. 5.5 months, respectively; HR, 3.87; P = 0.02)., Conclusions: In MET exon 14-altered cancers treated with a MET TKI, a comprehensive analysis of previously unknown and known genomic factors did not identify a genomic mechanism of primary resistance. Instead, MET expression correlated with benefit, suggesting the potential role of interrogating the proteome in addition to the genome in confirmatory prospective trials., (©2020 American Association for Cancer Research.)

Introduction: Although next-generation sequencing (NGS) has brought insight into critical mutations or pathways (e.g., DNA damage sensing and repair) involved in the etiology of many cancers and has directed new screening, prevention, and therapeutic approaches for patients and families, it has only recently been used in malignant pleural mesotheliomas (MPMs)., Methods: We analyzed the blood samples from patients with MPM using the NGS platform MSK-IMPACT to explore cancer-predisposing genes. The loss-of-function variants or pathogenic entries were identified, and clinicopathologic information was collected., Results: Of 84 patients with MPM, 12% (10 of 84) had pathogenic variants. Clinical characteristics were similar between cohorts, although patients with germline pathogenic variants were more likely to have more than two first-degree family members with cancer than those without germline mutations (40% versus 12%; Fisher's exact test, p < 0.05). Novel, deleterious variants in mesotheliomas included MutS homolog 3 (1% [one of 84]; 95% confidence interval [CI]: 0%-7%), breast cancer gene 1-associated ring domain 1 (1% [one of 84]; 95% CI: 0%-7%), and RecQ-like helicase 4 (2% [two of 84]; 95% CI: 0%-9%). Pathogenic variants previously reported on germline testing in patients with mesotheliomas were breast cancer gene 1-associated protein 1 (4% [three of 84]; 95% CI: 1%-10%), breast cancer gene 2 (1% [one of 84]; 95% CI: 0%-7%), and MRE11 homolog, double strand break repair nuclease (1% [one of 84]; 95% CI: 0%-7%). One patient (1% [one of 84]; 95% CI: 0%-7%) had a likely pathogenic alteration in SHQ1, H/ACA ribonucleoprotein assembly factor that has not been associated with a heritable susceptibility to cancer., Conclusions: Our study lends further support for the role of aberrations in DNA damage repair genes in the pathogenesis of MPMs and suggests that targeting the members of these pathways for screening and treatment warrants further study., (Copyright © 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Introduction: MNNG HOS Transforming gene (MET) amplification and MET exon 14 (METex14) alterations in lung cancers affect sensitivity to MET proto-oncogene, receptor tyrosine kinase (MET [also known by the alias hepatocyte growth factor receptor]) inhibitors. Fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), and immunohistochemistry (IHC) have been used to evaluate MET dependency. Here, we have determined the association of MET IHC with METex14 mutations and MET amplification., Methods: We collected data on a tri-institutional cohort from the Lung Cancer Mutation Consortium. All patients had metastatic lung adenocarcinomas and no prior targeted therapies. MET IHC positivity was defined by an H-score of 200 or higher using SP44 antibody. MET amplification was defined by copy number fold change of 1.8x or more with use of NGS or a MET-to-centromere of chromosome 7 ratio greater than 2.2 with use of FISH., Results: We tested tissue from 181 patients for MET IHC, MET amplification, and METex14 mutations. Overall, 71 of 181 patients (39%) were MET IHC-positive, three of 181 (2%) were MET-amplified, and two of 181 (1%) harbored METex14 mutations. Of the MET-amplified cases, two were FISH positive with MET-to-centromere of chromosome 7 ratios of 3.1 and 3.3, one case was NGS positive with a fold change of 4.4x, and one of the three cases was MET IHC-positive. Of the 71 IHC-positive cases, one (1%) was MET-amplified and two (3%) were METex14-mutated. Of the MET IHC-negative cases, two of 110 (2%) were MET-amplified., Conclusions: In this study, nearly all MET IHC-positive cases were negative for MET amplification or METex14 mutations. MET IHC can also miss patients with MET amplification. The limited number of MET-amplified cases in this cohort makes it challenging to demonstrate an association between MET IHC and MET amplification. Nevertheless, IHC appears to be an inefficient screen for these genomic changes. MET amplification or METex14 mutations can best be detected by FISH and a multiplex NGS panel., (Copyright © 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)