While conventional treatments are often used to treat estrogen receptor α (ERα)-, progesterone receptor (PR)-, or human epidermal growth factor receptor 2 (HER2/ERBB2)-expressing tumors, the development of resistance poses a significant challenge, particularly in the context of triple-negative breast cancer (TNBC), which lacks these markers [7,8]. The gene discussed is ESR1; the disease is triple-negative breast carcinoma.