['To explore the mechanism of miR-21 involved in the development of renal cell carcinoma.', "Cell proliferation and apoptosis were measured after repression of miR-21 expression by antisense oligonucleotides. miR-21 targets were scanned using target prediction programs. After reduction of miR-21, Fas ligand and metalloproteinase inhibitor 3 (TIMP3) expression and luciferase activity were detected by Western blot and luciferase reporter assay. The effect of TIMP3 on miR-21-induced cell survival was determined by transfection with TIMP3 lacking 3' untranslated region and miR-21.", "The reduction of miR-21 by antisense oligonucleotides inhibited cell proliferation and induced cell apoptosis by activation of caspase pathway in renal cell carcinoma cells. Moreover, bioinformatics analysis revealed that miR-21 has the potential to regulate multiple apoptosis-related genes. The reduction of miR-21 inhibited Fas ligand and TIMP3 expression by targeting the binding site within the 3' untranslated region. Finally, the introduction of TIMP3 cDNA without 3' untranslated region abrogated miR-21-induced cell survival."] Does miR-21 modulate cell apoptosis by targeting multiple genes in renal cell carcinoma?