After the transfection of miR-421 mimics and miR-421 inhibitor, CMTM4 expression decreased in RCC cells from the miR-mimic transfection group and increased in the miR-inhibitor-treated group (Fig. 4H), indicating that CMTM4 served as the direct target of miR-421. This evidence concerns the gene CMTM4 and renal cell carcinoma.