Besides, we selected the median of the miR-4443 relative expression(ΔCt = 6.91) as cut-off value and after analysis we found that miR-4443 had no significant differences in age, chemotherapy regimens, tumor stage, lymph nodes stage, estrogen receptor status, progesterone receptor status and Her-2 status of breast cancer patients. The gene discussed is ESR1; the disease is breast carcinoma.