Adult type diffuse gliomas are therefore classified as isocitrate dehydrogenase (IDH)-mutant astrocytoma (graded CNS WHO 2/3/4), IDH mutant and 1p/19q codeleted oligodendroglioma (graded CNS WHO 2/3) and glioblastoma (GBM) IDH-wildtype (graded CNS WHO 4). This evidence concerns the gene IDH3A and glioblastoma.