Fig. 6

The number of methylation alterations increases over time and with higher-grade tumours. A The number of differentially methylated positions (DMPs) between the primary and relapse tumour (Δβ > 0.3) varied between the patients (one stacked bar per patient). Black colour shows the number of DMPs that are hypomethylated in the relapse tumour compared to the primary tumour. The grey colour means number of hypermethylated DMPs in the relapse compared to the primary tumour. B The number of DMPs was significantly higher (p-value < 0.05, denoted by *) in the methylation superfamily termed other embryonal tumours (AT/RT etc.) than the others except for diffuse HGG. Note that significance could not be calculated against groups with only one sample. Diffuse HGG and medulloblastoma both had significantly more DMPs than LGG. C The number of DMPs (y-axis) is significantly increased (p-value = 0.023; Cox proportional hazard regression model test) with longer relapse times (x-axis). D The DMPs were significantly (p-value < 0.01; two-sided wilcox test) enriched in regions that were not associated with a gene and decreased in 1st Exon, 5’UTR, Exon boundaries, TSS1500 (transcription start site and 1500 bp away) and TSS200 (transcription start site and 200 bp away) regions compared to the distribution of the array (first black bar). * denotes significant p-value < 0.01. E The CNA profiles of the paired primary and relapse samples were inspected visually for differences (gains/amplifications/deletions) and classified as “CNA heterogeneity” or “CNA homogeneity”. The patients are grouped based on the methylation superfamily classification of the primary tumour. Abbreviations: Choroid plexus – Choroid plexus tumours. Diffuse glioma – Diffuse glioma, MAPK altered, cell cycle-activated. LGG – low-grade glial/glioneuronal/neuroepithelial tumours. Neuroep. PATZ – Neuroepithelial tumour with PATZ1 fusion. Embryonal tumour – Other embryonal tumours. Diffuse HGG – Paediatric-type diffuse high-grade gliomas