Understanding the genetic basis for cholangiocarcinoma.

Cholangiocarcinoma is associated with several different risk factors, many of which have known genetic associations. Advances in our understanding of the human genome have translated to the development of gene specific and whole genome assays for identifying gene variants and other alterations associated with cancer development. An improved understanding of the inherited genetic variants associated with risk of cholangiocarcinoma has the potential to improve our understanding of the basic biology of cholangiocarcinoma, enhance the performance of risk stratification models for identifying individuals at highest risk for cholangiocarcinoma, and identifying genetic variants associated with predisposition to cholangiocarcinoma in families with multiple affected individuals. It is increasingly recognized that major cancer-causing mutations or other gene alterations associated with familial risk of multiple cancers can also occur as germline events in individuals with apparently sporadically occurring cancer. In this chapter we review the major risk factors for cholangiocarcinoma as well as known gene variants associated with these risk factors, gene variants that have been associated with cholangiocarcinoma as the result of interrogation of candidate genes known to be associated with putative cancer causing pathways in cholangiocarcinoma, as well as the prevalence of major cancer causing genetic aberrations shown to be inherited in the germline of patients with sporadically developed cholangiocarcinoma. There has not yet been any large-scale genome wide association study of cholangiocarcinoma, and the results from such a study are eagerly anticipated.