ERBB2 and breast cancer: According to the clinical classification of intrinsic subtype in breast cancer [25], 9 patients (22.0%) were luminal A subtype, 23 patients (56.1%) were luminal B subtype, 6 patients (14.6%) were human epidermal growth factor receptor 2 (HER2) subtype and three patients (7.3%) were basal-like subtype.