IDH1 and central nervous system cancer: Gliomas are highly hypoxic tumors.114, 115, 116 As outlined above, it has previously been shown that hypoxic cells may rely more on reductive glutamine metabolism to produce citrate (and thereby lipids) than normoxic cells.30 Both IDH1 and 2 have potential roles in hypoxia‐induced reductive carboxylation,29, 31 suggesting that this pathway may be perturbed in IDH1‐mutated gliomas.