PARP1 and neoplasm: Exploitation of this relationship, provides the rationale to target basal-like breast tumors using inhibitors of poly [ADP-ribose] polymerase 1 (PARP1; involved in single-stranded DNA break repair), since it is postulated that pharmaceutical inhibition of PARP1 in combination with the pre-existing DNA repair dysfunction from BRCA1 deficiency underlies a situation of synthetic lethality for tumor cells, yet minimal toxicity to normal cells [146].