Exploring the potential role of Opisthorchis felineus infection in cholangiocarcinogenesis.

The relationship between the liver fluke, Opisthorchis felineus (Of) and cholangiocarcinoma (CCA) has been assessed by a limited number of studies. In the case of animal models, such studies have pointed towards a causal association between Of infection and CCA. As per these studies, Of has the ability to interfere with DNA excision repair systems through the generation of reactive oxygen and nitrogen species. It can also cause accumulation of by-products generated via lipid peroxidation and is also involved in the production of oxysterol like compounds, hence possess the ability to mutate different genes. Although chalangiocarcinogenis through Of infection in humans is not established, but hospital based studies, case studies and case-controlled studies as well as the analysis of medical statistics, especially from Russian Federation, point towards a strong correlation between them. The aim of this work is to present the current understanding of the association between Of and CCA. On the basis of available studies, this work identifies an array of factors linked with Of infection, which have been independently identified as cancer inducers in various other studies. These factors point towards a possible causative link between Of infection and CCA induction in humans but this observation warrants for more epidemiological, clinical and pathological studies to conclusively state Of to be a CCA inducer in humans. However, Of infection, which is currently placed in group 3 of IARC classification for CCA should be re-classified to a higher group of cancer inducers.