Comprehensive Characterization of Somatic Mutation Timing Reveals the Evolutionary Trajectory of Lung Adenocarcinoma in Chinese Patients

Abstract

Lung adenocarcinoma (LUAD) is a heterogeneous disease with substantial genomic differences between individuals of Chinese and European ancestry. Deciphering the timing of driver mutations may lead to insights into tumor evolution that can inform diagnostic and therapeutic approaches for LUAD. Here, we conducted whole-genome sequencing on LUAD samples from 251 patients with Chinese ancestry to reconstruct the evolutionary trajectories of somatic alterations, especially those across the non-coding regions. Tobacco-related mutations preferentially occurred early and plateaued at 28 packs of cigarettes per year. Well-known driver mutations (e.g., EGFR, TP53, and RB1) also occurred at the early stage, displaying ancestry heterogeneity among smokers. In contrast to exogenous mutagens, endogenous mutagen-related alterations (APOBEC) occurred late. The 3’UTR was the most frequently altered non-coding element in LUAD, with recurrent disrupting mutations in the 3’UTR of SFTPB and SFTPA1. Unlike other cancer types, TERT promoter mutations were observed specifically among female LUAD patients. Clustered mutations (e.g., doublet-base substitutions, multi-base substitutions, and kataegis) influenced LUAD evolution and were overrepresented in driver genes. These findings provide insights into the dynamic nature of genomic alterations during lung tumorigenesis.