Prevalence of the EGFR T790M and other resistance mutations in the Australian population and histopathological correlation in a small subset of cases

Roger H. Kim*, Anna Lapuk, James Harraway, Eric Lee, Michael Walsh, Eleni Topkas, Victoria Jones, Julie Burn, Tina Baillie, Cathy Lim, Kambin Nejad, Anita Muljono, Eric Gagne, Melissa K. McConechy, Yesser Zein, Fiona Maclean, Anthony J. Gill, Ana Cristina Vargas

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We sought to review the prevalence of EGFR T790M and other EGFR mutations associated with either proven or probable tyrosine kinase inhibitor (TKI) resistance in the Australasian lung cancer population and to perform histopathological correlation in a subset of cases. Retrospective statistical analysis was performed on a set of targeted lung cancer gene mutation tests (FIND IT gene panel) performed at Sonic Healthcare during 2018 and early 2019. A total of 1833 lung adenocarcinoma tumour samples underwent somatic mutation testing. EGFR mutations were found in 28% (n=514) of patients, in whom 9.3% (n=48) T790M mutations were present (always combined with other EGFR mutations) and 4.8% (n=25) exon 20 insertions were found. We also compared the prevalence of EGFR mutations identified in our population with that of the four largest publicly available lung cancer cohorts (total n=576 samples). Finally, a subset of 38 samples of primary/and or metastatic lung adenocarcinomas from 23 patients, including five with serial biopsies, underwent detailed morphological analysis. No reproducible morphological correlates were found to be associated with T790M, exon 20 resistance mutations or rarer co-occurring EGFR mutations. Although this may be subject to referral bias towards patients with resistant disease, the incidence of EGFR and T790M mutations is higher in this series from an Australasian population than in other similar publicly available lung adenocarcinoma cohorts. We conclude that histopathological features cannot be used to predict the acquisition of EGFR resistance.

Original languageEnglish
Pages (from-to)410-420
Number of pages11
JournalPathology
Volume52
Issue number4
DOIs
Publication statusPublished - 1 Jun 2020

Keywords

  • epidermal growth factor receptor (EGFR) mutation
  • epidermal growth factor/antagonist and inhibitor
  • histological subtyping
  • molecular testing
  • Non-small-cell lung cancer (NSCLC)
  • T790M mutation

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