Objective To investigate the effect of overexpression of miRNA-4465 on invasion and metastasis of breast cancer MDA-MB-231 cells and its mechanism.Methods MiRNA-4465 minics was transfected into the MDA-MB-231 cells,and real-time PCR was used to detect the expression of miRNA-4465.Transwell assay was used to investigate the migration and invasion capability of cells after being transfected.Bioinformatics analysis were performed to predict the potential targets of miRNA-4465,and finally,luciferase reporter plasmids assay and west-ern blot was used to confirm the potential target of miRNA-4465.Results Comparing with negative control group, the expression of miRNA-4465 in miRNA-4465 minics group was increased significantly.Transwell migration assay showed that migration capability of cells in miRNA-4465 minics group was decreased(P =0.001);transwell inva-sion assay showed that invasion capability of cells in miRNA-4465 minics group was decreased(P =0.010).Lucif-erase reporter plasmids assay showed that comparing with the negative control +psiCHECK2-EZH2 3’UTR(wild type),the fluorescence activity of miRNA-4465 minics +psiCHECK2-EZH2 3’UTR(wild type)was decreased by 66%(P =0.001).Moreover,comparing with the negative control group,the expression of EZH2 protein was de-creased after transfecting miRNA-4465 minics into MDA-MB-231 cells.Conclusion MiRNA-4465 can suppress the invasion and metastasis of breast cancer MDA-MB-231 cells,which may be related to the regulation of EZH2.