IDH1 and glioma: With regard to molecular characteristics, mutation of IDH1 gene (R132H) as detected by immunohistochemistry was more frequently present in grade III gliomas than in GBMs (P < 0.0001 by Chi-square), and in GBMs its presence was a favorable prognostic marker being associated with a higher DFS and OS (P < 0.0001 and P = 0.0001, resp).