IDH2 and grade III glioma: IDH1/IDH2 mutation analysis by direct sequencing and anti-IDH1-R132H immunohistochemistry revealed 60% (32/53) of the primary tumors harboringIDH1 or IDH2 mutations, which included90% (26/29) of LGG, 38% (6/16) of anaplastic gliomas and none of the primary GBM.