The median survival for the total cohort of nine patients with de novo RRD glioblastoma was 36.8 months (95% confidence interval: 22-not reached), which was significantly longer than the other 450 adult patients with conventional IDH-wildtype glioblastoma lacking somatic hypermutation and mismatch repair deficiency (median survival of 15.5 months, 95% confidence interval: 14.7–17.9, p < 0.001). Here, IDH1 is linked to glioblastoma.