There is evidence that p53 induces resistance to methylating (TMZ) and chloroethylating (nimustine, carmustine, or lomustine) anticancer drugs in glioma cells, modulating the transcription of DNA repair genes such as O-6 methylguanine-DNA methyltransferase (MGMT), an enzyme that removes methyl and chloroethyl groups from the O6-position of guanine [170,171]. This evidence concerns the gene MGMT and glioma.