IDH1 and glioma: Occurrence of somatic mutations in genes encoding the replication-independent histone H3 variant H3.3 and the canonical histone H3.1, the presence of mutant IDH1 protein in spatially and temporally restricted neural precursors, deregulated expression/activity of epigenetic enzymes may lead to aberrant histone modification and DNA methylation profiles which are intimately linked to glioma pathology.