In particular, for patients with invasive breast cancer, the statuses of hormone receptor (HR: estrogen receptor (ER) or progesterone receptor (PR))) and human epidermal growth factor receptor 2 (HER2) status using immunohistochemical (IHC) staining are the most helpful markers for the treatment decisions of patients with breast cancer in clinical practice. This evidence concerns the gene ERBB2 and invasive breast carcinoma.