According to the Surveillance, Epidemiology, and End Results (SEER) Program database, compared to IDC, ILC is associated with larger tumor size, older diagnosis age, advanced stage, lower histological grade, higher estrogen receptor (ER)/progesterone receptor (PR) expression, and lower human epidermal growth factor receptor 2 (HER-2) expression. This evidence concerns the gene ESR1 and neoplasm.