There were highly significant differences between grade II and III IDH-mut astrocytomas [n = 43/37; median OS (95%-confidence interval (CI)) 12.9 (11.9–13.9)/7.1 (5.5–8.7) years; p < 0.01] and between grade II and III IDH1-R132H-nm gliomas (n = 31/53; median OS (95% CI) 6.6 (2.4–10.8)/1.9 (1.0–2.8) years; p < 0.01). This evidence concerns the gene IDH1 and glioma.