Subgroup analysis based on the type of immunohistochemistry showed a higher risk of ER+ breast cancer in patients with EMS (OR 0.91% CI 0.86–0.97, p = 0.005), whereas no significant correlation was observed between EMS and ER– breast cancer (OR 1.00; 95% CI 0.94–1.06, p = 0.89) (Table 2). This evidence concerns the gene ESR1 and breast cancer.