Novel Potential Biomarkers for Opisthorchis viverrini Infection and Associated Cholangiocarcinoma.

Background/Aim: Early detection of disease is a pivotal factor for determining prognosis and clinical outcome of patients with cancer. As cholangiocarcinoma (CCA) is currently difficult to detect and most cases of such cancer present with late-stage disease at the time of initial diagnosis, we employed proteomic analysis of the bile to identify potential candidate biomarkers for Opisthorchis viverrini (OV)-associated CCA. Materials and Methods: Proteins in pooled bile samples from patients with CCA and OV infection, with CCA without OV infection, with OV infection but no CCA, and with neither OV infection nor CCA were separated by 15% sodium dodecyl sulfate- polyacrylamide gel electrophoresis, in-gel trypsin digestion and analyzed by liquid chromatography-tandem mass spectrometry. Results: According to our analysis, three proteins, namely aristaless-like homeobox1 isoform X1 (ALX1), major histocompatibility complex polypeptide- related sequence A (MICA), and uncharacterized protein C14orf105 isoform X12 were found to be potential markers for OV infection, as they were predominantly found in all OV-infected groups. Although these proteins were detected in both OV-infected patients with and without CCA, their abundance was 2.90-, 7.06-and 3.65-fold higher, respectively, in those with CCA. In patients with CCA, potential novel biomarkers wre immunoglobulin heavy chain, translocated in liposarcoma (TLS), visual system homeobox 2 (VSX2) and an unnamed protein product. Conclusion: We provided novel information regarding potential biomarkers for OV infection and CCA. These two protein profiles could benefit diagnosis as well as monitoring of CCA.