HER2-targeted agents that have been approved for markets include the mAbs trastuzumab and pertuzumab, the inhibitors of ERBB family tyrosine kinase neratinib, afatinib, and pyrotinib, the conjugated agents trastuzumab-emtansine (T-DM1) and tratuzumab-hyaluronidase-oysk, and the dimerization inhibitors of EGFR/HER2 tyrosine kinase lapatinib (Table 2); they are mainly approved for the treatment of breast cancer. Here, ERBB2 is linked to breast cancer.