Survival by IDH1 mutation status. No IDH2 mutations were detected. Where DNA was available all cases without an IDH1 mutation were pyrosequenced for the common IDH2 mutations. a) All glioblastoma (GB) and anaplastic astrocytoma (AA) patients only. Kaplan-Meier plots of survival of patients who’s tumours had wild type IDH1 alleles and those with one mutated allele. b) Assessing the prognostic value of IDH1 mutation in AA and GB shows that in both tumour types mutation is associated with a better outcome.