However, the ratio of pyruvate dehydrogenase flux to citrate synthase flux (VPDH/VCS, i.e. the percent of total mitochondrial oxidation fueled by glucose oxidation, S1 Fig) increased in all obesity-associated tumor types in the presence of insulin (100 nM); in contrast, all three obesity-independent cell lines showed no increase in glucose oxidation in response to insulin (Fig 2B). This evidence concerns the gene CS and obesity due to melanocortin 4 receptor deficiency.