In light of previous reports showing that PTEN can negatively regulate hTERT in hepatocellular carcinoma, renal carcinoma, and glioma cells and that PI3K/AKT acts downstream of PTEN, we hypothesized that PTEN might inhibit tumor progression by suppressing the PI3K/AKT/hTERT pathway. The gene discussed is PTEN; the disease is central nervous system cancer.