The loss of PTEN function by genetic alterations and/or epigenetic, transcriptional, and post-translational mechanisms is an important event involved in tumor malignancy and progression in many different human cancers including glioma, melanoma, and breast, prostate, lung, colon, or endometrial carcinoma, among others [12,13,14,15,16]. This evidence concerns the gene PTEN and glioma.