Several ADCs, such as trastuzumab emtansine (anti-HER2 antibody linked to the microtubule inhibitor maytansine), trastuzumab deruxtecan (anti-HER2 antibody linked to the topoisomerase inhibitor deruxtecan), enfortumab vedotin (anti-NECTIN4 antibody linked to the microtubule inhibitor monomethyl auristatin E), and sacituzumab govitecan (anti-TROP2 antibody linked to the topoisomerase inhibitor SN-38), are currently approved by the US Food and Drug Administration (FDA) for the treatment of breast cancer and urothelial cancer. This evidence concerns the gene NECTIN4 and breast carcinoma.