To investigate whether GBM tumorigenicity necessitates alterations in PTEN directly, we introduced lentivirus expressing the HA-tagged PTEN mutants, PTEN4E (S380E/T382E/T383E/S385E) or PTEN4A (S380A/T382A/T383A/S385A)45, or WT PTEN cDNAs into GXP GBMs, T98G and control NS, that could be distinguished from endogenous PTEN by anti-HA detection (Supplementary Fig. 6a). This evidence concerns the gene PTEN and glioblastoma.