Background: We previously reported that modulation of cytokeratin18 induces pleomorphism of liver cells, higher cell motility, and higher drug sensitivity to sorafenib treatment of hepatoma cells. These relationships were established by in vitro experiments. The aim of this study was to determine the in vivo association between cytokeratin expression and tumor behavior, as well as cancer stem cells of hepatocellular carcinoma and intra-hepatic cholangiocarcinoma in Taiwan. Methods: Cytokeratins and sal-like protein 4 expression was determined in 83 hepatocellular carcinoma and 30 intra-hepatic cholangiocarcinoma specimens by immunohistochemistry. The relationship between cytokeratins and sal-like protein 4 expression with hepatitis virus infection, clinicopathologic factors, and survival was analyzed. Further, the correlation among cytokeratins and sal-like protein 4 expression was studied. Results: In addition to cytokeratin8/18, the expression of cytokeratin7/19 and sal-like protein 4 was noted in hepatocellular carcinoma; however, only cytokeratin19 expression had a significant correlation with poor overall survival and poor disease-free survival. The expression of cytokeratins and sal-like protein 4 was not correlated with hepatitis virus infection. The expression of cytokeratin19, but not 7, 8, and 18, was correlated with sal-like protein 4 expression in hepatocellular carcinoma. Cytokeratin7 expression was decreased and the sal-like protein 4 expression was absent in all 30 intra-hepatic cholangiocarcinoma cases. The expression of cytokeratins had not statistically significant correlation with overall and disease-free survival in patients with intra-hepatic cholangiocarcinoma. Conclusions: The expression of cytokeratin19 was associated with sal-like protein 4 expression, as well as poor overall and disease-free survival in hepatocellular carcinoma patients in Taiwan.
Keywords: cholangiocarcinoma; cytokeratin; hepatocellular carcinoma; sal-like protein 4.