Breast cancer can be categorized into molecular subtypes based on estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, namely, Luminal A, Luminal B, HER2-enriched, and triple-negative breast cancer (TNBC) [2]. The gene discussed is ERBB2; the disease is triple-negative breast carcinoma.