GPBAR1 and cholangiocarcinoma: Owing to its role in the pathogenesis of various diseases such as nonalcoholic steatohepatitis, hepatic diseases associated with cholestasis (primary sclerosing cholangitis and primary biliary cholangitis), polycystic liver disease, cholangiocarcinoma, portal hypertension, cirrhosis, and sepsis, TGR5 is being investigated as the potential therapeutic target in these diseases [13-16].