PTEN and glioblastoma: For this reason, in the light of accumulating evidence suggesting that the PTEN/PI3K/AKT/mTOR pathway is frequently deregulated in GBM and of recent data unveiling its involvement in cancer stem cell maintenance, we have focused our study on the kinase complex mTOR with the purpose to understand the role of mTORC2 in GBM biology compared with PI3K and mTORC1.