Fig. 1.

Primary mismatch repair-deficient IDH-mutant astrocytomas form a distinct methylation group. a t-distributed stochastic neighbour embedding (t-SNE) analysis of 32 primary MMR-deficient IDH-mutant astrocytomas with 128 reference cases from 4 methylation groups of IDH-mutant gliomas (n = 32 for each methylation group). Recurrent hypermutant tumors with treatment induced MMR defects in reference cohort are marked with a bold black border. b Age distribution of primary MMR-deficient astrocytoma cases (n = 19) compared to reference cohort. Black line represents median (PMMRDIA, 14y; A supra, 34y; HGA supra, 41y; A infra, 37y; O, 47,5). Age of patients with PMMRDIA is significantly younger compared to all other groups (p < 0.0001). c Gender ratio of primary MMR-deficient astrocytoma cases (n = 32) compared to reference cohort (A supra n = 51; HGA supra n = 41; A infra n = 37; O n = 56). d MGMT promoter methylation status assessed by methylation profiling. PMMRDIA primary MMR-deficient astrocytoma, A supra astrocytoma supratentorial, HGA supra high-grade astrocytoma supratentorial, A infra astrocytoma infratentorial, O oligodendroglioma 1p/19q codeleted