Targeting the DNA repair defect in BRCA mutant cells as a therapeutic strategy

The discovery that BRCA1/2 mutant cells (defective in the homologous recombination pathway of DNA repair) are spectacularly sensitive to inhibition of the enzyme PARP (involved in base excision repair) suggests a new, low toxicity, approach to the treatment of women with breast cancers caused by BRCA mutations. As the PARP inhibitors have no effect on cells with functional homologous recombination, the hope is that the treatment will be specific for breast cancer cells. PARP-inhibiting chemotherapeutics may be able to make use of a ‘synthetic lethal’ effect as an alternative to conventional nonspecific cytotoxic anticancer treatments.