Administration of FGF19 has been reported to reduce liver damage in mouse models of intrahepatic and extrahepatic cholestasis [149,150]; however, the therapeutic potential of FGF19 is limited because of concerns about tumorigenicity, such as the development of hepatocellular carcinoma induced by ectopic overexpression of FGF19 in mice [151]. The gene discussed is FGF19; the disease is extrahepatic cholestasis.