ERBB2 and cardiomyopathy: The human epidermal growth factor receptor 2 [Her2/neu], for example, found on a subset (20–30%) of breast tumors [35], is a target for Trastuzumab which, due to Her2's wide expression in human tissues including the adult myocardium, has a variety of adverse drug side effects including instances of cardiomyopathy [36].