Triple-negative breast cancer (TNBC) is characterized by the lack of estrogen and progesterone hormone receptors (HR-negative) and lower or missing expression of human epidermal growth factor receptor 2 (HER2-negative [HER2-zero or HER2-low]) [3], which makes it a biologically heterogeneous cancer that is challenging to treat due to the limited access to effective treatment options [4]. The gene discussed is ERBB2; the disease is cancer.