Page 49 - SDIR5 Abstract book 21 12 2021.

POSTER PRESENTATIONS

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Methylation status of MGMT promoter in glioblastoma in Serbian patients: valuable marker
or not?

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Nikola Jovanović , Vesna Nikolov , Nataša Vidović , Vladimir J. Cvetković , Jelena Vitorović , Svetlana
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Tošić , Tatjana Mitrović , Tatjana Jevtović-Stoimenov
1 University of Niš, Faculty of Sciences and Mathematics, Department of Biology and Ecology, Višegradska 33, 18000
Niš, Serbia
2 University of Niš, Faculty of Medicine, Clinic of Neurosurgery, Clinical Center, 18000 Niš, Serbia
3 University of Niš, Faculty of Medicine, Pathology and Pathological Anatomy Center, 18000 Niš, Serbia
4 University of Niš, Faculty of Medicine, Institute of Biochemistry, 18000 Niš, Serbia

Background: Newly diagnosed glioblastomas (GBM) express remarkable genetic and morphological
heterogeneity, which is often encountered during a histopathological examination. The development of
reliable molecular markers is essential for further advancement in therapeutic and diagnostic procedures
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in GBM patients. This study aimed to evaluate the prognostic properties of MGMT (O -methylguanine-DNA
methyltransferase) promoter methylation status in a Serbian population of GBM patients. Material and
Methods: Patients (N=34) operated on the Neurosurgery Clinic (The University Clinical Centre of Niš, Serbia)
between 2013 and 2019 were included in this study. To confirm primary GBM diagnosis, the presence of
isocitrate dehydrogenase 1 (IDH1-R132H) mutation in samples was determined by Sanger direct
sequencing. Methylation-specific polymerase chain reaction method (MSP) was used for MGMT
methylation status evaluation. Results: Age (hazard ratio 1.0689, p = 0.0007), the extent of tumor resection
(hazard ratio 0.4093, p = 0.0004), and type of adjuvant chemotherapy (hazard ratio 0.1639, p = 0.0001)
were recognized as independent prognostic factors. Semi-quantitative MSP approach resulted in improved
detection sensitivity of MGMT methylation status compared to the qualitative MSP method. Among IDH-
wt homogenous cohort of GBM patients older than 50 years with complete/partial resection of the tumor,
overall survival of patients harboring hypermethylated MGMT was significantly longer (11±6.68 months) in
comparison with the unmethylated group (5.2±3.9 months) (KW-H(1,14)=3.4328, p=0.06).
Conclusion: In this study, hypermethylation of the MGMT promoter region was correlated with longer OS
within Serbian population of GBM patients. Given the relatively small cohort group, this correlation should
be further investigated in more comprehensive research.
Keywords: biomarkers, epigenomics, glioblastoma, methylation, prognosis
This study was supported by the Ministry of Education, Science and Technological Development of the
Republic of Serbia (contract number: 451-03-9/2021-14/200124).

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