An agent that has been engineered to covalently link the HER2-targeted monoclonal antibody trastuzumab with the maytansinoid microtubule inhibitor DM1 via a non-cleavable thioether (SMCC) linker, T-DM1 is a stable molecule designed to deliver DM1 selectively to HER2-overexpressing tumour cells while retaining trastuzumab’s mechanisms of action along with its system and downstream immune-mediated effects [48]. The gene discussed is ERBB2; the disease is neoplasm.