Cholangiocarcinoma: the role of genetic and epigenetic factors; current and prospective treatment with checkpoint inhibitors and immunotherapy.

Cholangiocarcinoma (CCA) represents 3% of all gastrointestinal cancers worldwide and is the second most common primary liver tumor after hepatocellular carcinoma. CCA is an aggressive tumor that involves the intrahepatic, perihilar and distal biliary tree, with a poor prognosis and an increasing incidence worldwide. Various genetic and epigenetic factors have been implicated in CCA development.