The aberrant methylation of the MGMT promoter in 40% of gliomas leads to the transcriptional repression of the gene and consequently to the loss of the encoded DNA repair enzyme that removes alkylating lesions induced by chemotherapeutic alkylating agents (such as bis-chloroethylnitrosourea (BCNU) and temozolomide (TMZ)) [15]. This evidence concerns the gene MGMT and glioma.