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. 2020 May 12:10:596.
doi: 10.3389/fonc.2020.00596. eCollection 2020.

Topographical Mapping of 436 Newly Diagnosed IDH Wildtype Glioblastoma With vs. Without MGMT Promoter Methylation

Fatih Incekara  1   2 , Sebastian R van der Voort  2 , Hendrikus J Dubbink  3 , Peggy N Atmodimedjo  3 , Rishi Nandoe Tewarie  4 , Geert Lycklama  5 , Arnaud J P E Vincent  1 , Johan M Kros  3 , Stefan Klein  2 , Martin van den Bent  6 , Marion Smits  2
Affiliations

Topographical Mapping of 436 Newly Diagnosed IDH Wildtype Glioblastoma With vs. Without MGMT Promoter Methylation

Fatih Incekara et al. Front Oncol. .

Abstract

Introduction: O6 -methylguanine-methyltransferase (MGMT) promoter methylation and isocitrate dehydrogenase (IDH) mutation status are important prognostic factors for patients with glioblastoma. There are conflicting reports about a differential topographical distribution of glioblastoma with vs. without MGMT promoter methylation, possibly caused by molecular heterogeneity in glioblastoma populations. We initiated this study to re-evaluate the topographical distribution of glioblastoma with vs. without MGMT promoter methylation in light of the updated WHO 2016 classification. Methods: Preoperative T2-weighted/FLAIR and postcontrast T1-weighted MRI scans of patients aged 18 year or older with IDH wildtype glioblastoma were collected. Tumors were semi-automatically segmented, and the topographical distribution between glioblastoma with vs. without MGMT promoter methylation was visualized using frequency heatmaps. Then, voxel-wise differences were analyzed using permutation testing with Threshold Free Cluster Enhancement. Results: Four hundred thirty-six IDH wildtype glioblastoma patients were included; 211 with and 225 without MGMT promoter methylation. Visual examination suggested that when compared with MGMT unmethylated glioblastoma, MGMT methylated glioblastoma were more frequently located near bifrontal and left occipital periventricular area and less frequently near the right occipital periventricular area. Statistical analyses, however, showed no significant difference in topographical distribution between MGMT methylated vs. MGMT unmethylated glioblastoma. Conclusions: This study re-evaluated the topographical distribution of MGMT promoter methylation in 436 newly diagnosed IDH wildtype glioblastoma, which is the largest homogenous IDH wildtype glioblastoma population to date. There was no statistically significant difference in anatomical localization between MGMT methylated vs. unmethylated IDH wildtype glioblastoma.

Keywords: MGMT; atlas; glioblastoma; heatmap; localization.

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Figures

Figure 1
Figure 1
Heatmaps of all 436 isocitrate dehydrogenase (IDH) wildtype glioblastoma.
Figure 2
Figure 2
Heatmaps of O6-methylguanine-methyltransferase (MGMT) methylated (N = 211) and unmethylated (N = 225) glioblastoma.
Figure 3
Figure 3
Frequency difference maps between MGMT methylated (N = 211) and unmethylated (N = 225) glioblastoma.
Figure 4
Figure 4
P-value maps of MGMT methylated (N = 211) and unmethylated (N = 225) glioblastoma.
See this image and copyright information in PMC

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