TRACERx: TRAcking non-small cell lung Cancer Evolution through therapy (Rx). Pilot Study. Multi-region sequencing of early-stage NSCLCs.

Deciphering the complexity of non-small cell lung cancer (NSCLC) evolutionary histories may elucidate the basis for its dismal outcome. We performed multi-region sequencing of early-stage NSCLCs. Spatial dissection revealed branched tumor evolution, with driver mutations occurring before and after subclonal diversification. Intra-tumor heterogeneity in DNA copy number alterations, translocations and endogenous APOBEC mutational processes demonstrates that NSCLC may follow multiple distinct evolutionary trajectories simultaneously. In smokers, despite maintained carcinogen exposure, temporal dissection reveals a relative decrease in smoking-related mutations during tumor progression, accompanied by an increase in APOBEC-related mutations. In the tumors from ex-smokers, genome-doubling occurred before subclonal diversification, suggesting prolonged latency before clinical detection. Multi-region sequencing demonstrates the relentless and heterogeneous nature of genomic instability processes in early-stage NSCLCs.EGA study EGAS00001000809