Our results indicated that (1) MTA2 expression was increased in RCC cells and was markedly correlated with high grade and poor survival rates of patients with RCC; (2) MTA2 did not affect RCC cell proliferation or cell cycle distribution; (3) MTA2 regulated the tumour metastasis of RCC cells and modulation of MMP-9 expression in vitro and in vivo; (4) miR-133b and MMP-9 expression in patients with RCC was negatively correlated with poor survival rates; (5) MTA2 knockdown inhibited RCC metastasis by targeting miR-133b and MMP-9 pathways. This evidence concerns the gene MMP9 and neoplasm.