V12Ha-Ras transgenic mice under the control of the GFAP promoter form astrocytomas that have the added genetic complexity of the aberrant expression of p16, p19, and PTEN while overexpressing EGFR, MDM2, and CDK4, with chromosomal rearrangements comparable to human astrocytomas [77,78,79]. This evidence concerns the gene PTEN and astrocytoma (excluding glioblastoma).