TRACERx reveals subclonal selection's impact on lung cancer evolution.

The TRACERx study analysed 1,644 tumour regions from 421 patients with non-small cell lung cancer to determine the relationship between intratumour heterogeneity and clinical outcome. The study found that mutations in 22 out of 40 common cancer genes were under significant subclonal selection, and large subclonal expansions were associated with positive subclonal selection. Subclonal whole genome doubling (WGD) was detected in 19% of tumours, and copy number heterogeneity was associated with extrathoracic relapse within 1 year after surgery. These data demonstrate the importance of clonal expansion, WGD and copy number instability in determining the timing and patterns of relapse in non-small cell lung cancer.