Evidence from two randomized clinical trials supports stratification of therapy according to the methylation status of the O6-methylguanine-methyltransferase MGMT gene promoter in the population of elderly glioblastoma patients (> 65 years in the NOA-08 study and > 60 years in the Nordic Glioma study) [3, 4]. This evidence concerns the gene MGMT and glioblastoma.