Based on cellular markers, breast cancer can be categorized into three main types: those with estrogen (ER) or progesterone receptors (PR), those with overexpression of epidermal growth factor-2 (HER-2), and those lacking ER, PR, and HER-2, known as triple-negative breast cancer (TNBC) (3-5). The gene discussed is ERBB2; the disease is breast carcinoma.