Comparison of the genomic background of MET-altered carcinomas of the lung: biological differences and analogies

Mod Pathol. 2019 May;32(5):627-638. doi: 10.1038/s41379-018-0182-8. Epub 2018 Nov 20.

Abstract

Although non-small-cell lung cancer is a leading cause of cancer-related deaths, the molecular characterization and classification of its genetic alterations has drastically changed treatment options and overall survival within the last few decades. In particular, tyrosine kinase inhibitors targeting specific molecular alterations, among other MET, have greatly improved the prognosis of non-small-cell lung cancer patients. Here, we compare the genomic background of a subset of non-small-cell lung cancer cases harboring either a MET high-level amplification (n = 24) or a MET exon 14 skipping mutation (n = 26), using next-generatison sequencing, fluorescence in situ hybridization, immunohistochemistry, and Nanostring nCounter® technology. We demonstrate that the MET-amplified cohort shows a higher genetic instability, compared with the mutant cohort (p < 0.001). Furthermore, MET mutations occur at high allele frequency and in the presence of co-occurring TP53 mutations (n = 7), as well as MDM2 (n = 7), CDK4 (n = 6), and HMGA2 (n = 5) co-amplifications. No other potential driver mutation has been detected. Conversely, in the MET-amplified group, we identify co-occurring pathogenic NRAS and KRAS mutations (n = 5) and a significantly higher number of TP53 mutations, compared with the MET-mutant cohort (p = 0.048). Of note, MET amplifications occur more frequently as subclonal events. Interestingly, despite the significantly (p = 0.00103) older age at diagnosis of stage IIIb/IV of MET-mutant patients (median 77 years), compared with MET high-level amplified patients (median 69 years), MET-mutant patients with advanced-stage tumors showed a significantly better prognosis at 12 months (p = 0.04). In conclusion, the two groups of MET genetic alterations differ, both clinically and genetically: our data strongly suggest that MET exon 14 skipping mutations represent an early driver mutation. In opposition, MET amplifications occur usually in the background of other strong genetic events and therefore MET amplifications should be interpreted in the context of each tumor's genetic background, rather than as an isolated driver event, especially when considering MET-specific treatment options.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antineoplastic Agents / therapeutic use
  • Biomarkers, Tumor / genetics*
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cyclin-Dependent Kinase 4 / genetics
  • Female
  • GTP Phosphohydrolases / genetics
  • Gene Amplification*
  • Genetic Predisposition to Disease
  • Genomic Instability
  • HMGA2 Protein / genetics
  • Humans
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / pathology
  • Male
  • Membrane Proteins / genetics
  • Middle Aged
  • Molecular Targeted Therapy
  • Mutation Rate
  • Mutation*
  • Phenotype
  • Prognosis
  • Protein Kinase Inhibitors / therapeutic use
  • Proto-Oncogene Proteins c-mdm2 / genetics
  • Proto-Oncogene Proteins c-met / antagonists & inhibitors
  • Proto-Oncogene Proteins c-met / genetics*
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Retrospective Studies
  • Tumor Suppressor Protein p53 / genetics

Substances

  • Antineoplastic Agents
  • Biomarkers, Tumor
  • HMGA2 Protein
  • HMGA2 protein, human
  • KRAS protein, human
  • Membrane Proteins
  • Protein Kinase Inhibitors
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • MDM2 protein, human
  • Proto-Oncogene Proteins c-mdm2
  • MET protein, human
  • Proto-Oncogene Proteins c-met
  • CDK4 protein, human
  • Cyclin-Dependent Kinase 4
  • GTP Phosphohydrolases
  • NRAS protein, human
  • Proto-Oncogene Proteins p21(ras)