IDH1 and glioblastoma: The R132H mutation in IDH1 was found in 60.5% (23/38) of patients with AA and 20.0% (13/65) of our patients with GBM (Groups 3 and 5), whereas all patients with ODG (Group 1) had a mutation either in IDH1 (n = 62) or IDH2 (n = 3), as determined by Sanger sequencing.