[Comment] Whole-genome sequencing in breast cancer: is it ready for clinical application?

In The Lancet Oncology, Daniella Black and colleagues1 report whole-genome sequencing (WGS) data of 2445 breast cancer tumours from a UK cohort (100 000 Genomes Project [100kGP]). As well as linking these data to clinical and mortality data, the authors externally validated their results in a Swedish cohort (SCAN-B) of 502 cases. By integrating driver mutations, mutational signatures, and structural variation (SV) burden, the authors show that, alongside a handful of drivers known from other tumour types, a single WGS assay could identify potentially actionable alterations in 656 (26·8%) of all 2445 breast cancer cases in the 100kGP cohort.