Although the majority of BLBCs overlap with triple-negative breast cancer (TNBC) (defined as lacking the expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)), about 20% of BLBCs are known to express ER or HER2 [3]. Here, ESR1 is linked to triple-negative breast carcinoma.