MET alterations in biphasic squamoid alveolar papillary renal cell carcinomas and clinicopathological features

Mod Pathol. 2021 Mar;34(3):647-659. doi: 10.1038/s41379-020-0645-6. Epub 2020 Aug 7.

Abstract

Biphasic squamoid alveolar papillary renal cell carcinoma (BSA-PRCC) is a recently studied lesion considered a morphologic variant of papillary renal cell carcinoma (RCC), more closely related to type 1. Considering the role of proto-oncogene MET in both sporadic type 1 papillary RCC and hereditary papillary RCC, we aimed to explore the role of MET activation in the oncogenesis of BSA-PRCC. We identified 17 patients with either unique (n = 14) or multiple (n = 3) BSA-PRCC, all localized, and performed an integrative analysis of MET status in 18 formalin-fixed paraffin-embedded tumors combining next-generation sequencing analysis, fluorescent in situ hybridization and immunohistochemistry. Trisomy 7 was found in 86% of tumors (14/16) without MET amplification at 7q31 (15/15). A pathogenic MET genetic variant was identified in 60% (9/15) of cases, at the germline level in 57% (4/7) of tested patients or at the somatic level (5/11). MET expression was observed in all tumors with a higher value of combined score in large cells (mean 97%, range 80-100%) than in small cells (mean 74%, range 10-100%) and was lower in two cases without MET copy number gain. In conclusion, our study provides additional evidence to consider biphasic squamoid alveolar papillary RCC as a morphological variant of type 1 papillary renal RCC. Our data strongly suggest that MET represents a major oncogenic driver gene in BSA-PRCC, harboring a higher frequency of MET mutation that encourages to further explore the benefice of anti-MET targeted therapies for aggressive BSA-PRCC.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics*
  • Carcinoma, Papillary / genetics*
  • Carcinoma, Papillary / pathology
  • Carcinoma, Renal Cell / genetics*
  • Carcinoma, Renal Cell / pathology
  • DNA Copy Number Variations
  • DNA Mutational Analysis
  • Female
  • Gene Dosage
  • Genetic Predisposition to Disease
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization, Fluorescence
  • Kidney Neoplasms / genetics*
  • Kidney Neoplasms / pathology
  • Male
  • Middle Aged
  • Mutation*
  • Paris
  • Phenotype
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-met / genetics*

Substances

  • Biomarkers, Tumor
  • MAS1 protein, human
  • Proto-Oncogene Mas
  • MET protein, human
  • Proto-Oncogene Proteins c-met