In clinical trials, poly (ADP-ribose) polymerase inhibitors (PARPi) versus chemotherapy resulted in significantly improved progression-free survival, manageable adverse event profiles, and favorable patient-reported outcomes (PROs) in patients with human epidermal growth factor receptor 2–negative (HER2−) advanced breast cancer (ABC) and germline BRCA1/2 mutations (gBRCA1/2mut). This evidence concerns the gene BRCA1 and aneurysmal bone cyst.