Fortunately, advances in molecular medicine have revealed critical markers, such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her2), and these have been especially helpful in further classifying certain types of breast cancers into distinctive functional groups [3], in addition to informing selection of patients for specific targeted treatment options [4,5]. Here, ESR1 is linked to breast carcinoma.