MGMT and glioblastoma: In addition, clinical outcome was analyzed in 63 GBM patients with or without BCNU-based chemotherapy at tumor recurrence, adjusted for potential clinical (age, extent of resection (EOR) at 1st surgery, TMZ at 1st diagnosis, treatment intensity at tumor recurrence) and molecular MGMT (O6-methylguanine DNA methyltransferase) promoter hypermethylation) prognostic factors.