ERBB2 and breast cancer: Incidence rate of breast cancer has been increased for several years, resulting from a combination of social and economic factors, including the postponement of childbearing, obesity and physical inactivity.1 Molecular studies have demonstrated that there were at least four molecular subtypes of breast cancer: luminal, basal, human epidermal growth factor receptor 2 (HER2)‐enriched and normal‐like.