ERBB2 and breast cancer: (12) Trastuzumab emtansine (T-DM1) that targets the HER2 receptors was the first ADC to be approved by the FDA for the treatment of breast cancer, followed by HER2-targeting and Trop-2-targeting ADCs, trastuzumab deruxtecan (T-DXd) and sacituzumab govitecan (SG), respectively.