These trends were similar to a recent study using 13C-MFA to investigate lung cancer cells (A549)27) and B-cells.21) However, the result is inconsistent with another 13C-MFA study examining MCF-7 cells, probably because of differences in culture conditions and experimental design.23) The result of this study also revealed that some αKG was converted into citrate (Cit) by the reversed reaction of isocitrate dehydrogenase (IDH) (Fig. 4). The gene discussed is IDH3A; the disease is lung carcinoma.