ERBB2 and breast cancer: Risk scoring tools in hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative early breast cancer are either based on a combination of clinicopathological factors and immunohistochemically detected tumor markers (e.g., the Nottingham Prognostic Index [NPI] and PREDICT) [1] or involve multigene expression profiles to complement pathological assessment and provide risk classification (e.g., Oncotype DX® and MammaPrint®) [2, 3].