Biliary tract cancers are relatively common malignant gastrointestinal
tumors in the elderly.
Claudins are integral components of tight junctions that play important roles in maintaining epithelial cell polarity, controlling paracellular diffusion, and regulating cell growth and differentiation. The expression profile of
claudins has been extensively characterized, but few reports exist on their expression in the normal and neoplastic biliary tract. Our aim was therefore to study
claudins by IHC reactions in normal and neoplastic biliary tract samples. We detected that
claudin expressions differ in the normal sample groups: the normal gallbladder strongly expressed
claudin-2, -3, -4, and -10, but only weak reactions were seen in normal intrahepatic bile ducts. Although each
cancer type expressed several
claudins with various intensities, only
claudin-4 presented especially strong immunoreactions in extrahepatic bile duct
cancers and gallbladder
carcinomas, whereas
claudin-1 and -10 presented in intrahepatic bile duct
cancers. Comparing the normal and
carcinoma groups, the most significant decrease was detected in the expression of
claudin-10. In conclusion, the expression pattern of
claudins is different in the various parts of the normal and neoplastic biliary tract; moreover, an unequivocal decrease was detected in the
carcinomas compared with their corresponding normal samples. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.