Interleukin-6 Expression on the Biliary Epithelia During Inflammation-Associated Biliary Carcinogenesis in Bilioenterostomized Hamsters

Abstract

Chronic inflammatory conditions of the biliary tree strongly predispose patients to biliary carcinoma. The aim of this study was to evaluate the role of interleukin-6 (IL-6) expression during biliary carcinogenesis in bilioenterostomized hamsters. Syrian hamsters were subjected to either a choledochoduodenostomy (CD, n=11) or a simple laparotomy (SL, n=10) and then received N-nitrosobis(2-oxopropyl)amine (BOP) treatment. The animals were sacrificed 20 wk after surgery and the development of biliary carcinoma, the presence and degree of cholangitis, and IL-6 expression on the biliary epithelia were examined histologically. In the CD group, eight hamsters (73%) demonstrated persistent cholangitis and six (55%) of them developed intrahepatic biliary carcinoma, while no hamster without cholangitis showed any biliary carcinoma. In the SL group, cholangitis was recognized in four hamsters (40%) and no development of biliary carcinoma was identified. A significantly high incidence of tumor development (P=0.024) and a close correlation between the presence of cholangitis and the occurrence of biliary carcinoma (P =0.013) were thus evident in the CD group. Moreover, the degree of cholangitis was significantly higher in the CD hamsters (P=0.041) and an IL-6 overexpression was identified in five hamsters that had undergone a CD, with a scattered expression on the intra- and extrahepatic biliary epithelia. Despite the fact that the induced biliary carcinomas showed a multicentric occurrence in the liver, these tumors originated from within the restricted area where IL-6 was expressed. A deregulated IL-6 overexpression on the biliary epithelia may therefore be involved in inflammation-associated biliary carcinogenesis in hamsters that have undergone a bilioenterostomy.