These results are in line with previous reports that FGF21 could be a biomarker of hepatic carcinogenesis, particularly that associated with hepatocyte stress (15) and that FGF21 deficiency can promote obesity-induced hepatocellular carcinoma, implying tumor suppressor activity of FGF21 (16). Here, FGF21 is linked to obesity due to melanocortin 4 receptor deficiency.