Expression of endogenous Galectin-1 and Galectin-3 in intrahepatic cholangiocarcinoma

Galectins, a family of beta -galactoside-binding animal lectins, might be i nvolved in tumor progression. In this study, the expression patterns of gal ectin-1 and -3 were examined immunohistochemically in intrahepatic cholangi ocarcinoma (ICC), with emphasis on its development and progression as well as its histopathologic features, by use of samples of normal intrahepatic b ile duct (n = 20), biliary epithelial dysplasia (n = 15), ICC (n = 40), and a cholangiocarcinoma cell line, CCKS1. In normal intrahepatic bile ducts, galectin-3 was constitutively but weakly expressed, whereas galectin-1 was not expressed. In hepatolithiasis, biliary epithelial dysplasia was strongl y positive for galectin-3 but negative for galectin-1. Galectin-3 was frequ ently and strongly expressed in the cytoplasm of well-differentiated ICCs, and its expression was significantly decreased and less intense or even abs ent in poorly differentiated ICCs. Galectin-1 was expressed in carcinoma ce lls in ICC, and its incidence and extent were correlated with histologic de differentiation of ICC. Proliferative cell nuclear antigen (PCNA) labeling index (LI) was higher in ICC cases positive for galectin-1 than in those th at were negative. Galectin-1 was strongly expressed in cancerous stroma of ICC, and this stromal expression was related to histologic dedifferentiatio n of ICC. In the carcinoma cell line CCKS1, galectin-1 and -3 were expresse d in the cytoplasm of carcinoma cells, and galectin-1 was additionally dete cted in the culture medium. These results suggest that galectin-1 was newly expressed on carcinoma cells of ICC, and its overexpression seems to be as sociated with neoplastic progression and proliferative activities, and the expression of galectin-1 in cancerous stroma may also be related to the pro gression of ICC. Galectin-3 expression in epithelial cells is up-regulated in the preneoplastic and early neoplastic stages of ICC, although galectin- 3 tends to disappear at later stages of ICC. HUM PATHOL 32:302-310. Copyrig ht (C) 2001 by W.B. Saunders Company.