BRCA1 and breast cancer: Therapeutically active compounds included platinum derivatives and PARP inhibitors, for which genomic and/or functional HRD have been shown to predict responses in BC patients,6, 10, 11, 15 anthracyclines, for which sensitivities were reported in BRCA1/BRCA2‐deficient tumors30 as well as DNA synthesis inhibitors, since recent research has carved out critical roles of HR components in DNA replication fork protection and reactivation.23