FH and glioma: By analyzing The Cancer Genome Atlas (TCGA) data, we found that OGDH mRNA levels were significantly downregulated in IDH-mutated gliomas compared with other TCA cycle enzymes, including citrate synthase (CS), succinate dehydrogenase complex subunit B (SDHB), and fumarate hydratase (FH) (Fig. 1b; Supplementary Fig. S1a).