The comparison of the distribution of tumor cells in the different compartments (Fig. 1a) and the proliferating fraction (Fig. 3f) suggests that perivascular tumor cells less actively divide in IDH1 mutant astrocytoma (p = 0.0002), IDH1 mutant high grade astrocytoma (p = 0.0005), and IDH wild-type glioblastoma (p = 0.0064). Here, IDH1 is linked to astrocytoma (excluding glioblastoma).