Given that BRCA1/2 repress basal-like genes under normal physiologic conditions and are commonly mutated in basal-like breast cancer [21], this breast cancer subtype is representative of cancers with homologous recombination deficiency (HRD), which are more likely to be sensitive to poly adenosine diphosphate (ADP) ribose polymerase inhibitors (PARPi) [22]. This evidence concerns the gene BRCA1 and breast cancer.