Expression of microsomal prostaglandin E synthase-1 in human hepatocelluar carcinoma.

Background/Aims: The objective of this study was to evaluate the expression of microsomal prostaglandin E synthase-1 (mPGES-1) in hepatocellular carcinoma (HCC) tissues. Methods: Forty surgically resected HCC tissues with adjacent non-tumorous liver tissues and 14 surgically resected, histologically normal liver tissues were used. The immunohistochemical expressions of the mPGES-1 protein in these HCC tissues and normal control livers were analysed. mPGES-1 mRNA expression was also analysed by the real-time polymerase chain reaction method using the same tissues. Results: Microsomal prostaglandin E synthase-1 was not expressed in hepatocytes but instead in vascular endothelial cells and bile duct epithelial cells in normal liver tissues. The mPGES-1 expression in HCC tissues was significantly greater than its expression in the non-tumorous tissues. All types of HCC expressed more mPGES-1 than normal or hepatitis livers, and the levels of mPGES-1 expression in poorly differentiated HCC were similar to the levels in well-differentiated HCC. The mPGES-1 mRNA expression paralleled its protein expression in these tumorous and non-tumorous tissues. Conclusions: The present study is the first to demonstrate a high expression of mPGES-1 in well-differentiated HCC as well as in poorly differentiated HCC. These findings suggest that mPGES-1 may play a role in the advanced as well as early stage of hepatocarcinogenesis.