Poly (ADP-ribose) polymerase inhibition enhances trastuzumab antitumour activity in HER2 overexpressing breast cancer

Aim: Poly (ADP-ribose) polymerase (PARP) inhibitors have shown promising results in Breast Cancer (BRCA) deficient breast cancer, but not in molecularly unselected patient populations. Two lines of research in this field are needed: the identification of novel subsets of patients that could potentially benefit from PARP inhibitors and the discovery of suitable targeted therapies for combination strategies. Methods: We tested PARP inhibition, alone or combined with the anti-HER2 antibody trastuzumab on HER2+ breast cancer. We used two PARP inhibitors in clinical development,