Based on its molecular characteristics, it can be divided into three groups: hormone-positive (either with the expression of estrogen receptors (ER+) or progesterone receptors (PR+)), with the expression of human epidermal receptor 2 (HER2+), and triple-negative breast cancer (TNBC), which does not show expression of hormone receptors and HER2 (ER−, PR−, HER2−) [2,4]. The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.