Later analyses of the data that included data on MGMT promoter methylation allowed to conclude if a “monotherapy” with either radiation or chemotherapy for elderly GBM patients is planned, patients with tumors with methylated MGMT promoter would benefit from alkylating chemotherapy with temozolomide whereas patients with tumors with unmethylated MGMT promoter should undergo radiotherapy alone, preferentially a hypofractionated scheme [40, 41]. The gene discussed is MGMT; the disease is glioblastoma.