It is, however, possible that the 2-oxoacid substrate preference of IDH variants (and other 2OG using enzymes) varies in a manner dependent on the localized availability of 2OG/2OG derivatives, both of which could be affected by nutrition and, at least in the case of 2OG, by multiple metabolic pathways, some of which may be altered in disease, as it is the case for IDH variant bearing cancer cells (4, 13, 14, 15). This evidence concerns the gene IDH2 and cancer.