Several risk factors for the development of CTRCD in women with HER2+ breast cancer receiving trastuzumab-based therapies have been described (e.g., age, low–normal LVEF, diabetes, hypertension, and anthracycline exposure) [4,9], but these risk factors in isolation are insufficient to accurately determine patient-specific CTRCD risk [8,9,16]. The gene discussed is ERBB2; the disease is diabetes mellitus.