Two anti-HER2 ADCs, ado-trastuzumab emtansine (T-DM1; Kadcyla®) and fam-trastuzumab deruxtecan-nxki (T-DXd; Enhertu®) are approved as adjuvant therapies and rescue treatments for patients with HER2-positive breast cancer, and most recently HER2-low breast cancer [32,33,34]. Here, ERBB2 is linked to breast cancer.