Mutations in BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) and the association with breast cancer were first discovered by teams of researchers led by Mary-Claire King (BRCA1) in 19908 and Alan Ashworth and Sir Mike Stratton (BRCA2) in 1995.9 When BRCA is mutated, the HRR repair cascade is interrupted, leading to an HRR defect that results in a failure to correctly repair DNA DSBs10 (Fig 1B). This evidence concerns the gene BRCA1 and breast cancer.