Comparative genomic analysis indicated that gains or the losses of various chromosomes carrying important oncogenes or tumor suppressor genes, respectively, including the gain of PIK3C2B, MDM4, KIT, PDGFRA, EGFR, GLI1, CDK4 and MDM2 and the loss of p16INK4a/p14ARF, PTEN and RB1, were common to all GBM tumors analyzed; whereas area-specific alterations included the gain of 14q32.33, where AKT1 is localized [10]. The gene discussed is PTEN; the disease is glioblastoma.