(A) Reverse transcription-quantitative polymerase chain reaction was conducted to detect the expression level of miR-138 in WM451 cells transfected with scramble miR (NC), miR-138 mimics or miR-138 inhibitor, respectively. (B) Western blot was conducted to detect the protein level of HIF-1α in WM451 cells transfected with scramble miRNA (NC), miR-138 mimics or miR-138 inhibitor, respectively. Control: WM451 cells without any transfection. **P<0.01 vs. control. miR, microRNA; HIF-1α, hypoxia-inducible factor-1α.