For examples, silencing of the DNA repair gene O6‐methylguanine‐DNA methyltransferase (MGMT) due to promoter DNA methylation sensitizes GBM tumors to temozolomide (TMZ, an alkylating agent) and MGMT promoter methylation is a prognostic marker for a favorable outcome in GBM patients treated with TMZ [7]. This evidence concerns the gene MGMT and glioblastoma.