ERBB2 and cancer: Patients harboring specific molecular aberrations could derive benefit from targeted therapies in the second- or later-line setting.10-15 Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase transmembrane receptor, and its overexpression/amplification, which has been identified as an oncogenic driver in multiple malignancies, is associated with a poor prognosis in some cancers.