Given all these limitations, there is a need for the development of new diagnostic modalities. Of particular interest is the quest of tumor markers secreted or shed in bile by tumor cells developing in the biliary tract. Proteomics and metabolomics have been
used for this purpose. Although proteomics studies have allowed describing a catalogue of several hundreds of proteins in bile, up to now they have not identified and validated new biomarkers for the clinical use [22, 23]. NMR spectroscopy studies in patients with cholangiocarcinoma have reported significant changes in metabolic profiling of bile such as high levels of lactate [24] or reduced levels of phosphatidylcholine, bile acids and cholesterol [25]. However, the potential of this approach for early diagnosis has still to be confirmed in the clinical setting.