The mode of tumour progression in combined hepatocellular carcinoma and cholangiocarcinoma: an immunohistochemical analysis of E-cadherin, alpha-catenin and beta-catenin.

To investigate the mode of progression of combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC). An immunohistochemical study for E-cadherin (ECD) and alpha- and beta-catenins was performed on 29 cases of cHCC-CC. Reduced expression of ECD was significantly correlated with the tumour grade of the hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) components, intrahepatic metastasis (IM) of HCC, IM of CC, and vascular invasion of CC (p < 0.05, respectively). There was a significant relationship between the reduced expression of beta-catenin and the tumour grade of HCC components (p < 0.05). Cases showing concurrent intrahepatic metastasis composed of HCC, CC, or both, numbered 6, 5, and 2, respectively. The expression patterns of ECD and beta-catenin of IM were similar to those of primary lesion in most cases. On the other hand, expression of ECD and beta-catenin of IM of HCC component were preserved, even though those of the primary sites were reduced in two cases and one case, respectively. ECD and beta-catenin were significantly correlated with tumour differentiation and tumour progression. Preserved or recovered ECD and beta-catenin expression may be of beneficial effect for re-establishing the tissue architecture at the metastatic site.