IDH1 and astrocytoma (excluding glioblastoma): IDH-mutant astrocytomas of CNS WHO grade 4 were numerically more often located in the frontal lobes (p = 0.118) (Table 1), and a gross total resection was numerically more often performed in these patients than in patients with CNS WHO grade 2 or 3 tumors (p = 0.177) (Table S1).