Our study assessed miR-556-3p’s role in breast cancer cells. A total of 65 cases of breast cancer tissue samples were retrospectively analyzed to detect miR-556-3p level by PCR and analyze survival time and 30 normal breast tissues were included as a control group. Breast cancer cells were cultured followed by analysis of cell proliferation by MTT, cell invasion by transwell assay. miR-556-3p level was significantly upregulated in breast cancer patients compared to control group (P P In vitro experiments, cell activity and invasion were positively correlated with miR-556-3p level (P P