Besides germline BRCA1/2-mutant cancers, there has been increasing evidence that PARP inhibitors may have a role in somatic BRCA1/2-mutant cancers, or cancers associated with HR deficiency [3,25], and more recently, possibly even tumors deficient in chromatin regulation like cancers with ARID1A mutations [76]. The gene discussed is BRCA1; the disease is cancer.