Targeted therapies that have improved outcomes in breast cancers and are currently in the clinical armamentarium include CDK kinase inhibitors and PI3K kinase inhibitors in metastatic ER-positive breast cancers, PARP inhibitors for cancers with BRCA1 or BRCA2 mutations, and immune checkpoint inhibitors for triple-negative cancers and cancers with microsatellite instability [3,4,5,6]. This evidence concerns the gene BRCA1 and cancer.