Mucosal damage in pancreaticobiliary maljunction is stronger in the gallbladder than in the bile duct

The frequency of gallbladder carcinoma is high in pancreaticobiliary maljunction (PBM), and the mechanism of carcinogenesis is not well understood.The expression of γH2AX, the most sensitive marker for detecting DNA damage, was analyzed using immunohistochemistry in patients with PBM, in which the gallbladder and bile duct were simultaneously resected. Gallbladder and bile ducts were evaluated in non-neoplastic regions in 13 cases of PBM without cancer in the gallbladder and bile ducts.The median frequencies of γH2AX expression in the bile duct and gallbladder within the same case were 5.9% (range 1.7-12.05%) and 9.9% (range 2.8-25%), respectively, and were significantly higher in the gallbladder mucosa (P < 0.0004). γH2AX expression strongly correlated in the bile duct and gallbladder (r = 0.9436, P < 0.0001). PBM caused marked mucosal damage to the gallbladder.Mucosal damage may be involved in carcinogenesis, which may be useful for predicting malignant transformation.