Epigenetic Aberrations in Cholangiocarcinoma: Potential Biomarkers and Promising Target for Novel Therapeutic Strategies

Cholangiocarcinoma (CCA) is a notoriously lethal malignancy arising from the biliary tract epithelium.While relatively rare, incidence rates have increased markedly worldwide in the past decade. Although definiterisk factors such as primary sclerosing cholangitis, liver fluke infestation, and hepatolithiasis have been welldocumented,the cause of CCA remains unknown for most cases. An importance of not only genetic alterations butalso epigenetic aberrations, including promoter hypermethylation and histone modifications, has been indicatedfor the processes of carcinogenesis and pathogenesis of CCA. This review focuses on epigenetic mechanismsinvolved in CCA genesis, with special emphasis on their applicability as potential biomarkers for diagnosis,prognosis and prediction as well as promising targets for novel therapeutic strategies.