Biliary Tract Cancer: Implicated Immune-Mediated Pathways and Their Associated Potential Targets.

There is a well-established link between biliary tract cancers (BTC) and chronic inflammatory conditions such as primary sclerosing cholangitis, chronic cholecystitis, chronic cholelithiasis, liver fluke-associated infestations, and chronic viral hepatic infections. These associated risk factors highlight the potential for development of immune-modulatory agents in this poor-prognostic disease group with limited treatment options. Clinical trials have evaluated the role of immune cells, inflammatory biomarkers, vaccines, cytokines, adoptive cell therapy, and immune checkpoint inhibitors in patients with BTC. Although these have demonstrated the importance of the immune environment in BTC, currently none of the immune-based therapies have been approved for use in this disease group. The role of immunomodulatory agents is a developing field and has yet to find its way 'from bench to bedside' in BTC.