Epidermal growth factor receptor (EGFR) mutation status before and after acquired resistance to EGFR tyrosine kinase inhibitors in patients with lung adenocarcinoma

Abstract

Objective: To investigate epidermal growth factor receptor (EGFR) mutation status in lung adenocarcinomas before and after acquiring resistance to EGFR tyrosine kinase inhibitors (TKIs) using ARMS method followed by further verification using droplet digital PCR technique. Methods: Twenty qualified patients were included, among them 13 were male and 7 were female patients. Before EGFR-TKIs treatment, 5 patients were EGFR wild-type by ARMS, and the other 15 patients had L858R or 19-del point mutations. The time to progression varied from 4 to 18 months. Mutation of exons 18, 19, 20 and 21 were detected by ARMS, and were verified by droplet digital PCR system method. Results: EGFR wild-type status was unchanged before and after acquired resistance to EGFR-TKIs in 5 lung adenocarcinoma patients. Alteration of EGFR mutation status occurred in 10 of the 15 patients with pre-treatment L858R or 19-del mutations. Among them, T790M mutation was found in 8 patients, L858R became G719X plus S768I mutation in one patient, and 19-del converted into wild-type in one other patient. Conclusions: T790M mutation is the primary type of EGFR mutation in lung adenocarcinomas with acquired resistance to EGFR-TKIs therapy. Acquired resistance to EGFR-TKIs dose not lead to the alteration of EGFR status in pre-treatment EGFR wild-type patients, but can alter EGFR mutation status in pre-treatment EGFR mutant patients.