Treatment for newly diagnosed glioblastomas currently involves surgical resection followed by Temozolomide chemotherapy with concomitant radiotherapy, and then 6 cycles of Temozolomide in adjuvant. According to many studies, only those patients not expressing the enzyme repair MGMT benefit from the adjunction of Temozolomide. Therefore, many patients receive unnecessary treatment. The aim of this project is to compare different techniques for analysis of MGMT in order to choose the approach with the best cost/utility ratio, which will allow the selection of patients likely to respond to TMZ chemotherapy during the first course of GBM treatment.