Different expression of cyclooxygenase-2 in biliary epithelia of bile duct cancer with or without pancreaticobiliary maljunction.

Background: Cyclooxygenase-2 (COX-2) has been reported to play an important role in the pathogenesis of a variety of cancers. Little is known about the relationship between bile duct cancer associated with pancreaticobiliary maljunction (PBM) and COX-2.
Materials and Methods: We compared the expression of COX-2 in bile duct epithelium in bile duct cancer with or without PBM.
Results: Immunohistochemical analysis showed that the rate of positive COX-2 expression was 42.9% for cancerous lesions and 7.1% for noncancerous lesions in cases of bile duct cancer without PBM. On the other hand, no positive expression of COX-2 was observed in cancerous lesion of bile duct cancer with PBM. Twenty % of the noncancerous bile duct mucosa with PBM was positive for COX-2.
Conclusion: COX-2 is expressed in bile duct cancer while it is not expressed in bile duct cancer accompanied by PBM.