ERBB2 and breast cancer: Breast cancer subtypes by immunohistochemical method were identified in 340 cases: HER2 negative luminal type (HER2-negative and hormone receptor positive), HER2 positive type (HER2 positive irrespective of hormone receptors status), and triple negative (TN) type (negative for hormone receptors and HER2) were 205 (35.4%), 103 (17.8%), and 32 (5.5%), respectively.