IDH1 and cancer: The reductive metabolism of glutamine, mediated by IDH1, adds extensively to lipogenesis in cancer cells (81) (Figure 4), and which is partially facilitated by an increase in PDK1 (53, 82) and c-Myc (76, 83) in a HIF1-dependent manner, but it is primarily determined by the relative abundance of citrate and α-KG (83, 84).