MDH2 and hepatocellular carcinoma: Other upregulated metabolic genes that showed higher expression in HUH7 cells include NADPH oxidase 4 (NOX4), phosphogluconate dehydrogenase (PGD in PPP) and AKR1B10 (among the topmost upregulated metabolic gene in human HCC datasets), as well as key players in cholesterol metabolism (e.g. SQLE, FDPS, IDI1) and TCA cycle (e.g. MDH2, IDH1/2, IDH3A/B, FH, ME1/2) (Additional file 8: Table S7).