Around 10-24% of the breast cancer population constitutes invasive breast cancer with triple-negative breast cancer (TNBC) markers, which are tumors that do not display estrogen receptor (ER) or progesterone receptor (PR), and are characterized by non-overexpression of the HER2 gene; they are often high-grade tumors with distinct histological groups [2]. Here, ESR1 is linked to breast cancer.