ERBB2 and breast cancer: Breast cancer is the most common cancer in Chinese women [1]; of these cancers, 20–25% have overexpressed or gene amplified human epidermal growth factor receptor 2 (HER-2) [2], a subtype with high malignancy, distant metastasis rate and mortality, and relatively short disease-free survival (DFS) and overall survival (OS) [3, 4] and, therefore, a high need for clinical attention.