These 44 shared miRNAs were significantly associated with key aspects of breast cancer progression, including conditions such as progesterone receptor-negative breast cancer, estrogen receptor-negative breast cancer, HER2-negative breast cancer, ductal carcinoma of the breast, and invasive breast carcinoma, which are consistent with the subtype of breast cancer we studied. The gene discussed is ESR1; the disease is breast ductal adenocarcinoma.