Association between O-6-Methylguanine-DNA Methyltransferase (MGMT) promoter gene methylation status and Isocitrate Dehydrogenase 1 (IDH1) R132H status in Balinese glioblastoma patients

Background: Glioblastoma is a malignant tumor with a poor prognosis. The treatment of glioblastoma is a combination of surgery, chemotherapy, and radiotherapy is treatment Determination of the methylation status of O-6-MGMT is essential to predict the response of alkylating agent treatment. This study aims to determine the association between O-6-Methylguanine-DNA Methyltransferase (MGMT) promoter gene methylation status and Isocitrate Dehydrogenase 1 (IDH1) R132H status in Balinese glioblastoma patients. Methods: This was a cross-sectional study of glioblastoma patients at Prof. Dr. I.G.N.G. Ngoerah Hospital Denpasar who were diagnosed between 1 January 2018 and 31 December 2020. Clinicopathology data was obtained from the Anatomical Pathology Laboratory and Hospital Information System data. IDH1 R132H mutation status was determined by immunohistochemistry. The methylation status of O-6-MGMT was determined by MS-PCR testing. Results: Based on this study's results, 59.4% of glioblastomas had hypermethylated O-6-MGMT, and 40.6% were hypomethylated. There was no significant association between methylation status of 0-6-MGMT with IDH status (p=0.435), age (p=0.722), sex (p=0.642), and lobe extension (p=1.000) Conclusion: MGMT methylation status cannot be predicted from clinicopathological parameters; molecular examination is an absolute test for identifying MGMT mutations.