ERBB2 and breast cancer: For instance, ado-trastuzumab emtansine (T-DM1, Kadcyla) (20, 21) and fam-trastuzumab deruxtecan-nxki (T-Dax, Enhertu) (22, 23) have been approved for human epidermal growth factor receptor 2 (HER2)+ breast cancers.