PARP1 and breast cancer: Of note, PARP inhibitors are typically well-tolerated drugs and can be added to standard chemotherapy to synergistically treat mammary tumors with germline mutations with either high, intermediate, or low penetrance in the homologous recombination pathway, and in the single-strand and double-strand DNA break repair machinery in hopes of improving the clinical outcome and quality of life of TNBC patients with germline mutations in BRCA1, BRCA2, PALB2, RAD51, p53, and CHEK2 [188,193,194,195,196,197,198,199,200,201].