Objective:To determine the biological function of miR-122 in kidney tumors and the relationship between sprouty2 and miR-122. Methods:RT-qPCR was performed to measure the levels of miR-122 in 32 primary renal cell carcinoma (RCC) and their adjacent non-malignant tissue samples. The miR-122 inhibitor was successfully transfected into 786-0 and CAKI-1 cell lines. CCK-8 assays and cell cycle assays were performed to analyze the proliferation after transfection,respectively. The regulative function of miR-122 on sprouty2 was evaluated by Western blot assays. Dual luciferase reporting assays were performed to confirm whether sprouty2 is a direct target of miR-122. Results:In RCC specimens,miR-122 was significantly up-regulated (P < 0.05). The inhibition of miR-122 suppressed the proliferation (P < 0.05),induced cell cycle arrest (P < 0.05), and promoted the expression of sprouty2 protein levels (P < 0.05) in 786-0 and CAKI-1 cell lines. Sprouty2 was identified as a new target of miR-122 by dual luciferase,and fluorescence value was significantly increased (P < 0.05). Conclusion:miRNA promotes the proliferation of renal cancer cells and sprouty2 gene may be a target of miR-122. [Key words] miR-122;sprouty2;renal cell carcinoma;proliferation