Triple-negative breast cancer (TNBC), the most lethal of breast cancers, is defined by a lack of expression of estrogen receptors (ER) and progesterone receptors (PR), without amplification of the human epidermal growth factor receptor (HER2/neu), which predisposes patients to fewer options for treatment [7, 8]. The gene discussed is ESR1; the disease is triple-negative breast carcinoma.