Background: MicroRNA is a type of non-coding small RNA involved in regulating genes and signaling pathways through incomplete complementation with target genes. Recent research supports key roles of miRNA in the formation and development of human glioma. Methods: The relative quantity of miR-34a was initially determined in human glioma A172 cells and glioma tissues. Next, we analyzed the impact of miR-34a on A172 cell viability with the MU assay. The effects of miR-34a overexpression on apoptosis were confirmed with flow cytometry and Hoechst staining experiments. We further defined the target genes of miR-34a using immunofluorescence and Western blot. Results: MiR-34a expression was significantly reduced in human glioma A172 cells and glioma tissue, compared with normal glial cells and tissue samples. Our MU data suggest that up-regulation of miR-34a inhibits cell viability while suppression of miR-34a enhances cell viability. Flow cytometry and Hoechst staining results revealed increased rates of apoptosis in A172 human glioma cells overexpressing miR-34a. Using immunofluorescence and Western blot analyses, we identified NOX2 as a target of miR-34a in A172 cells. Conclusion: MiR-34a serves as a tumor suppressor in human glioma mainly by decreasing NOX2 expression. (C) 2014 Published by Elsevier Inc.