Role of epigenetic alterations in cholangiocarcinoma

Intrahepatic cholangiocarcinomas are rare malignant epithelial liver tumors arising from intrahepatic bile ducts. The prognosis of affected patients is poor. Several risk factors, including hepatolithiasis, liver fluke infection, and anatomical abnormalities associated with inflammation of the biliary tract have been described. At present, little is known about the cellular and molecular mechanisms leading to the development of cholangiocarcinoma. In recent years, in addition to genetic alterations, epigenetic inactivation of (tumor suppressor) genes by promoter CpG island hypermethylation has been recognized as an important and alternative mechanism in tumorigenesis. This review discusses the epi-genetic inactivation of different tumor suppressor genes in cholangiocarcinoma.