Isocitrate dehydrogenase (IDH) is another TCA cycle enzyme that converts isocitrate to alpha-ketoglutarate, and IDH1/IDH2 mutations have been reported in a number of cancers including leukemia, melanomas, oligodendrogliomas, and astrocytomas [78]. This evidence concerns the gene IDH1 and astrocytoma (excluding glioblastoma).