The RTK/Ras/PI(3)K pathway was found to be altered in 86–90% of GBM cases studied.9,10 Combined activation of the Ras and AKT pathways has been shown to induce glioblastoma tumor formation in mice.100 The AKT signaling pathway plays a pivotal role in the progression of grade III anaplastic astrocytoma to grade IV glioblastoma multiforme. This evidence concerns the gene AKT1 and anaplastic astrocytoma.