Fig. 1

Gene-expression based classification of high-grade gliomas and corresponding survival analyses. Principal component analysis of microarray GE profiling of 119 high-grade gliomas. In total, 131 data points are represented as 11 samples were duplicated allowing to monitor the batch effect correction. The genes associated with the highest standard deviation were selected (n = 120 genes) for the analysis and the tumors were color-coded according to their location (a) or mutational histone H3 status (b). Four groups were defined in the upper left panel corresponding to cortical (yellow), thalamic (black), pontine (pink) and non-thalamic midline (grey) glioma. In the right panel, the samples were divided in 4 subgroups according to the mutational status of histone H3 genes: H3.3-G34R (blue), H3.3-K27M (light green), H3.1-K27M (dark green) mutated tumors and tumors without any alteration of either H3F3A, HIST1H3B and HIST2H3A genes (grey). c Kaplan–Meier of the overall survival of patients with a high-grade glioma stratified by their location. DIPG (green) and thalamic (black) tumors are associated with the shortest overall survival (median of 11.1 months and 10.8 months respectively). The midline tumors (grey) which are located outside the thalamus show the most favorable prognosis. The subgroup of cortical tumors (yellow) shows an intermediate phenotype (median survival 30.5 months). Log rank test p-value < 0.0001. d Kaplan–Meier survival curves of patients with a midline HGG stratified by both tumor location and H3-K27 mutational status. The overall survival is rather similar for all tumor subgroups (overall median survival about 10.8, 13.86, 10.02, 10.5 months for K27M DIPG, WT DIPG, K27M midline, WT thalamus, respectively) except for the WT non-thalamic midline tumors presenting a much better prognosis. Log rank test p-value < 0.0001