ERBB2 and invasive breast carcinoma: Human epidermal growth factor receptor 2 (HER2) gene amplification and subsequent protein overexpression is a strong prognostic and predictive biomarker in invasive breast carcinoma (IBC), assessed by immunohistochemistry (IHC) and/or in situ hybridization (ISH) per the guidelines issued by the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) [1].