The study investigates the role of microRNA-21 (miR-21) in human glioblastoma cells. MiRNAs are small noncoding RNA molecules that regulate gene expression by targeting mRNA for degradation or translational inhibition. The authors found that miR-21 is highly overexpressed in human glioblastoma tissues and cell lines compared to nonneoplastic brain tissues and glial cells. Inhibiting miR-21 in glioblastoma cells led to increased caspase activation and apoptotic cell death, suggesting that miR-21 functions as an antiapoptotic factor. The study also showed that miR-21 may contribute to the malignant phenotype by blocking the expression of critical apoptosis-related genes. These findings highlight the potential therapeutic implications of targeting miR-21 in glioblastoma.The study investigates the role of microRNA-21 (miR-21) in human glioblastoma cells. MiRNAs are small noncoding RNA molecules that regulate gene expression by targeting mRNA for degradation or translational inhibition. The authors found that miR-21 is highly overexpressed in human glioblastoma tissues and cell lines compared to nonneoplastic brain tissues and glial cells. Inhibiting miR-21 in glioblastoma cells led to increased caspase activation and apoptotic cell death, suggesting that miR-21 functions as an antiapoptotic factor. The study also showed that miR-21 may contribute to the malignant phenotype by blocking the expression of critical apoptosis-related genes. These findings highlight the potential therapeutic implications of targeting miR-21 in glioblastoma.