Here, our data revealed that circMCTP2 deficiency impairs the cell proliferation and metastasis abilities in vitro, an effect that was removed by the co-transfection with OE-MDM2 plasmid, suggesting that circMCTP2 facilitates the BC cell proliferation and metastasis through regulating the miR-498/MDM2 axis. This evidence concerns the gene MDM2 and breast cancer.