ESR1 and breast cancer: The clinicopathological characteristics examined in this study included age at diagnosis, histopathological type, molecular type, tumor size, site of occurrence, lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), Ki-67, the Tumor Node Metastasis (TNM) stage, family history of breast cancer, and family history of other tumors.