ERBB2 and breast cancer: In Malaysia, breast cancer incidence accounted for 34.1% of all cancers among females in Malaysia.1 Recent research showed that half of breast cancers develop in women who have no identifiable breast cancer risk factor other than gender (female) and age (over 40 years).2 Human epidermal growth factor receptor 2 (HER2)-negative phenotypes, regardless of estrogen or progesterone status, have been reported as a marker for aggressive breast cancer.