The targetable mutation landscape of Chinese patients with non-small cell lung cancer.

Abstract

e13018 Background: In recent years, the prognosis of non-small cell lung cancer (NSCLC) patients has been substantially improved by targeted therapies against specific molecular aberrations, i.e. tyrosine kinase inhibitors (TKIs) for Epidermal Growth Factor Receptor ( EGFR) etc. Several genes have been suggested by NCCN guideline (v7.2017) to test for NSCLC patients, including EGFR, ALK, ROS1, BRAF, MET, RET, HER2 and KRAS. The aim of this study is to profile the landscape of actionable mutations in Chinese NSCLC patients. Methods: From 2015 to 2017 621 treatment naïve NSCLC patients enrolled in the affiliated cancer hospital of Zhengzhou University were included in this analysis. DNA was extracted from the FFPE biopsies of these patients and processed for target capture sequencing covering the exons and flanking splicing regions of the 8 genes suggested by NCCN guideline, as well as introns of ROS, ALK and RET. Results: In total, 593 out of the 621 NSCLC patients harbor one or more mutations in these 8 genes, accounting for 95.5% of all the cases. EGFR, ALK and HER2 are the top 3 mutants, with a frequency of 52%, 32% and 26% respectively. Genetic aberrations in BRAF, MET, ROS1, KRAS and RET occur in 22%, 18%, 16% and 14% of the patients. The most common variation is missense; T > G, C > T and C > A changes are more often observed than T > C, T > A and C > G; the median number of variants per sample is 2, ranging from 1 to 13. There are 418 mutations detected on EGFR, of which 206 (49.28%) are clinically relevant. EGFR L858R, Exon19 deletion, Exon20 insertion, G719, A750P were observed in 123 (29.43%), 43 (10.29%), 8 (1.91%), 6 (1.44%) and 6 (1.44%) cases respectively. Gene fusions were identified in 78 cases, and the EML4- ALK is the most common one occurred in 54 patients, other fusion genes include KIF5B- ALK (11) ， CCDC6- RET (4), CD74- ROS1 (4), EZR- ROS1 (2), ERC1- RET (1), , SDC4- ROS1 (1) and TCOF1- ROS1 (1). Conclusions: Target sequencing of the 8 genes suggested by NCCN guideline for NSCLC patients reveals essential information for designing personalized therapeutic regimen. Chinese patients, maybe other Asian countries also, may benefit more from this molecular testing, because of the high occurrence of actionable mutations.