The hazard ratios with 95% CI are visualized in a forest plot in Figure 3B. Within the IDH1 mutant LGG histological subtypes analysed separately for grade II and grade III tumours (Supplementary Figure S3), cg26969888 was a significant prognostic factor for OS in both grade II and grade III oligodendroglioma, as well as in grade III astrocytoma. This evidence concerns the gene IDH1 and oligodendroglioma.