The BTIC lines were generated from tumors from newly diagnosed and recurrent GBM patients [12–17], exhibit the ability to self-renew and differentiate into multiple neural cell lineages [14], encompass the diversity of molecular genetic alterations that are known to occur in human GBM patients (e.g. EGFR, PTEN, p53, IDH1 etc.)and are tumorigenic in orthotopic xenograft murine models [14, 18]. This evidence concerns the gene PTEN and glioblastoma.