Published online Apr 16, 2015. doi: 10.4253/wjge.v7.i4.308
Peer-review started: August 20, 2014
First decision: September 16, 2014
Revised: January 5, 2015
Accepted: January 18, 2015
Article in press: January 20, 2015
Published online: April 16, 2015
Biliary strictures present a diagnostic challenge and a conundrum, particularly when an initial work up including abdominal imaging and endoscopic retrograde cholangiopancreatography based sampling are non-diagnostic. Advances in endoscopic imaging have helped us diagnose these strictures better. However, even with modern technology, some strictures remain a diagnostic challenge. The proximity of bile fluid to the bile duct epithelia makes it an attractive option to investigate for bio-markers, which might be representative of the functions/abnormal changes taking place in the biliary system. A number of biomarkers in bile have been discovered recently in approaching biliary strictures with their potential future diagnostic utility, further supported by the immunohistochemical analysis of the resected tissue specimens. Novel biliary biomarkers especially carcinoembryonic cell adhesion molecule 6 and neutrophil gelatinase-associated lipocalin seem promising in differentiating malignant from benign biliary strictures. Recent developments in lipidomic profiling of bile are also very promising. Biliary biomarkers appear to complement endoscopic imaging in diagnosing malignant etiologies of biliary stricture. Future studies addressing these biomarkers need to be incorporated to the current endoscopic techniques to determine the best approach in determining the etiology of biliary strictures.
Core tip: Pancreato-biliary malignancies remain a diagnostic challenge despite advances in endoscopy and imaging. Serum carbohydrate antigen 19-9 which is the most commonly used tumor marker has not been able to complement the endoscopic techniques effectively. Bile fluid is a better representative of the pancreato-biliary malignancies and various tumor markers in bile have been described recently with advances in proteomics. Carcinoembryonic cell adhesion molecule 6, neutrophil gelatinase-associated lipocalin and other novel biliary markers seem promising with high sensitivities and specificities, little affected by the presence of inflammation or the degree of biliary obstruction. These are potential future tumor markers that can complement endoscopic techniques in diagnosing malignant biliary strictures.