BRCA1 and breast cancer: Breast cancer with BRCA1/2 mutations is emerging as a distinctive group of breast cancers that present at an earlier age with hallmarks of genomic instability and accumulation of DNA damage.1, 2, 3 Two poly (ADP-ribose) polymerase inhibitors (PARPi) are available as the therapeutic option (olaparib and talazoparib), but many patients do not derive benefit because of multiple primary and secondary resistance mechanisms and toxicities.4