Expression of MUC1, Thomsen-Friedenreich antigen, Tn, sialosyl-Tn, and alpha2,6-linked sialic acid in hepatocellular carcinomas and preneoplastic hepatocellular lesions.

The expression of epithelial mucins and Thomsen-Friedenreich-related antigens in preneoplastic and neoplastic hepatocellular lesions was systematically investigated using an in situ immunohistochemical staining approach. MUC1, MUC2, TF, sialosyl-TF, Tn, sialosyl-Tn, alpha2,3-linked sialic acid, and alpha2,6-linked sialic acid were examined in normal and cirrhotic human liver and in human hepatocellular carcinomas (HCCs) and cholangiocarcinomas. Normal hepatocytes and preneoplastic foci of altered hepatocytes did not express MUC1, MUC2, TF, Tn, s-Tn, or alpha2,6-linked sialic acid. In contrast, HCCs showed positive reactions for MUC1, TF, Tn, s-Tn, and alpha2,6-linked sialic acid. MUC2 was absent in normal biliary epithelial cells, but present in cholangiocarcinomas. The staining of MUC1, or s-Tn and alpha2,6-linked sialic acid in human normal liver tissues and various liver diseases did not change after specific treatments such as periodate oxidation or saponification, indicating that their expression in HCC does not result from incomplete glycosylation or low O-acetylation, respectively. MUC1, TF, Tn, s-Tn, and alpha2,6-linked sialic acid may be useful as indicators of progression of HCC in tissue sections, and perhaps also as targets for diagnostic and therapeutic approaches in vivo.