IDH3A and astrocytoma (excluding glioblastoma): Apart from the gap junction-coupled tumor network, bona fide glutamatergic synapses formed between neurons and glioma cells were found in tumor subpopulations of adult isocitrate dehydrogenase wildtype (IDH-wt) glioblastomas, adult isocitrate dehydrogenase mutant (IDH-mut) astrocytoma [12, 14], and pediatric histone-H3 mutant (H3K27M) diffuse midline gliomas (DMG) [14].