ERBB2 and breast cancer: Based on the induction of ADCC exerted by the anti-HER2 mAbs, preclinical studies have addressed the potential synergistic effect of either trastuzumab or trastuzumab emtansine (T-DM1) plus mAbs against the cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and the programmed cell death protein 1 (PD1),27,28 demonstrating a strong lymphocytic induction against BC cells.