IDH3A and glioblastoma: Primary GBM, which constitute 90-95% of GBM [9], differ from non-GBM with respect to DNA copy number [11], gene expression [11], DNA methylation [12-14], and isocitrate dehydrogenase (IDH) 1 or 2 gene mutation status [11-16], providing a molecular rationale for the two broad glioma subtypes of GBM and non-GBM.