Although HER2-enriched cancers may have a worse prognosis, they can be effectively treated with therapies targeting HER2 protein, such as Herceptin (chemical name: trastuzumab), Perjeta (chemical name: pertuzumab), and Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine) (3). Here, ERBB2 is linked to cancer.