BRCA1 and breast neoplasm: Previous observations provided strong circumstantial evidence that the brca1 and parp1 pathways could be dysfunctional in a significant subgroup of triple-negative and basal-like breast tumors and, therefore, that those pathways could be targeted for therapy 60, 63 tumors which lack BRCA1 are sensitive to the PARP inhibitors which result in synthetic lethality [26]