BRCA1 and cancer: The paradigm for this approach is the use of poly(ADP)-ribose polymerase inhibitors (PARPi) for the treatment of homologous recombination-deficient (HRD) cancers, which includes breast and ovarian tumors that are mutated in the HR genes BRCA1 and BRCA2 (Bryant et al., 2005; Farmer et al., 2005).