ERBB2 and breast cancer: Alternatively, the antibody-drug conjugate (ADC) trastuzumab emtansine (T-DM-1) consisting of the anti-HER2 mAb trastuzumab linked to the cytotoxic agent emtansine (DM-1), which enters and destroys the HER2-overexpressing cells by binding to tubulin, was successful in patients with advanced breast cancer (13, 14).