The expression of SBEM, p-PI3K, p-AKT, MMP1, MMP3, MMP9, CyclinD1, PCNA and CyclinB1 proteins in breast cancer cells transfected with miR-186-5p mimic was significantly decreased, and the proliferation of breast cancer cells was inhibited, indicating that miR-186-5p can degrade SBEM and inhibit phosphorylation of PI3K and AKT as well as the proliferation of cancer cells. The gene discussed is PCNA; the disease is breast carcinoma.