Evaluation of O6-methylguanine-DNA methyltransferase enzyme expression effect on survival of patients with Grade 4 brain astrocytoma

Background: High-grade astrocytoma (Grade 4) or glioblastoma multiforme (GBM) are deadly brain tumors. New therapies attempt to increase lifetime and quality of life in patients with malignant astrocytoma. O6-methylguanine-DNA methyltransferase (MGMT) enzyme expression may be eff ective in prognosis and response to treatment of these patients. Th e aim of this study was assessment of MGMT enzyme expression in patients with astrocytoma Grade 4. Materials and Methods: In this study, 48 patients with GBM that were treated with surgery, chemotherapy and radiotherapy were investigated and followed-up for 47 months for the survival rate. Pathology blocks of patients were examined for MGMT enzyme expression using immunohistochemistry method. Results: Th e patients were 34 males and 14 females. Th e ages ranged from 24 to 77 years, with a mean age of 53.52 ± 13.39 years. Th ere was no signifi cant diff erence between two groups (positive and negative MGMT enzyme expression) in overall survival (median [range] 11.5 [4-30] vs. 13 [5-22], P = 0.9). Th e results of our study showed that patients although who were undergone near total surgery had higher overall survival than the group of patients who had biopsy only however, it was not signifi cant. Patients who were treated with temozolomide (TMZ) (Temodal, Merck Canada) had signifi cant overall median survival (14.5) more than the patients who were treated with Procarbazine (Roche, Swiss)-Lomustine (Lilly, USA)-Vincristine (Lilly, USA) regimen (8.75) (P < 0.05). Conclusion: O6- methylguanine-DNA methyltransferase enzyme expression had no eff ect on survival of patients with Grade 4 brain astrocytoma TMZ may increase survival rate.