In vitro growth inhibitory assays on patient-derived glioma cell lines showed that telmisartan, at a concentration of 45 ± 0.06 μM, could suppress 50% of the malignant glioma U87 cell population, while PCR (Polymerase Chain Reaction) assays showed that AT1 expression in the untreated sample was high reinforcing the role which exhibits the AT1 receptors on glioma. This evidence concerns the gene AGTR1 and malignant glioma.