In breast cancer, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) are currently considered a milestone in the clinical decision-making process, providing crucial information about prognosis, and predicting response to cancer treatments (Gamble et al., 2021; Criscitiello et al., 2022). The gene discussed is ESR1; the disease is cancer.