PPARG and hepatocellular carcinoma: Recent studies have demonstrated that the methylxanthine derivative caffeine upregulated peroxisome proliferator-activated receptor gamma (PPARγ) expression in hepatocytes of Caucasian patients with ongoing hepatic fibrogenesis and Chinese patients with fully developed HCC, suggesting that the effects of caffeine vary among ethnic groups; thus, further studies are necessary to fully understand the underlying mechanisms (Gressner et al., 2009).