IDH1 and astrocytic tumor: It could be argued that a major reason for this difference might be the distinct mechanisms conducting H3K9 methylation in the two types of gliomas, i.e. IDH1 mutation dependent in oligodendrogliomas versus IDH1 mutation independent in high-grade astrocytic tumors, since IDH1 mutations are advanced as one of the most powerful favorable outcome predictors in gliomas [41, 42].