Serum and bile biomarkers for cholangiocarcinoma

To discuss recent studies proposing new markers in serum or bile for the diagnosis and prognosis of cholangiocarcinoma (CCA), which could help in the differential diagnosis between malignant and benign biliary disorders or for the surveillance of disorders at risk, including primitive sclerosing cholangitis.

In the last few years, efforts have been made to identify biomarkers with adequate diagnostic accuracy for CCA in serum or biological fluid. Studies have been focused on cytokines, growth factors or enzymes produced and secreted by CCA cells as well as on the proteomic analysis of serum and bile.

The serum levels of interleukin 6, trypsinogen, mucin-5AC, soluble fragment of cytokeratin 19 and the platelet-lymphocyte ratio have been recently shown to help in the diagnosis of CCA with, in some cases, a prognostic value. As far as bile is concerned, the ratio of pancreatic elastase/amylase, mucin-4, minichromosome maintenance replication protein and insulin-like growth factor 1 have been explored, with the insulin-like growth factor 1 biliary concentration capable of completely discriminating CCA from benign biliary disorders and pancreatic cancer. We have also discussed advances in the proteomic of serum and bile, which seem promising in identifying new markers for CCA.