To understand the role of the PTEN/PI3K/AKT/mTOR pathway in GBM cell viability and proliferation, we selectively inhibited PI3K, mTORC1 and mTORC2 in GL15, U87MG, U251 and U118 cells and performed MTT and BrdU incorporation assays. This evidence concerns the gene PTEN and glioblastoma.