Although monoclonal antibodies (e.g., trastuzumab) and tyrosine kinase inhibitors (TKIs) (e.g., lapatinib) have mostly been used in recent decades to treat HER2+ breast cancer patients [32–36], current regimens typically use a combination of taxanes, trastuzumab, and pertuzumab as first-line agents, with ado-trastuzumab emtansine (T-DMI) used as a second-line agent. Here, ERBB2 is linked to breast cancer.