Treatment for newly diagnosed glioblastomas (GBM) currently involves surgical resection followed by Temozolomide (TMZ) chemotherapy with concomitant radiotherapy, and then 6 cycles of TMZ in adjuvant (Stupp schedule). According to many studies, only those patients not expressing the enzyme repair MGMT benefit from the adjunction of TMZ. Therefore, many patients receive unnecessary treatment at an average cost of about 15,000 euros.