Downregulation of PTEN expression and suppression of its dephosphorylation activity induce proliferation and inhibit apoptosis of glioma cells through activation of the PI3-K-Akt-glycogen synthase kinase 3 (GSK3) pathway, suggesting that PTEN may be involved in inactivation of PI3-K signaling [14]. This evidence concerns the gene PTEN and central nervous system cancer.