Several clinical trials of PARPi are currently in progress for breast cancer with mutations in DNA repair genes, including PALB2. A phase II trial is underway for the evaluation of PARPi olaparib monotherapy in the treatment of metastatic breast cancer patients harboring germline/somatic mutations in non-BRCA1/BRCA2 DNA repair genes (NCT03344965). This evidence concerns the gene BRCA1 and breast cancer.