Significance of cyclooxygenase-2 expression in human primary hepatocellular carcinoma

AIM:To clarify the significance of cyclooxygenase-2(COX-2)expression in human primary hepatocellular carcinoma(HCC)and adjacent nontumorous tissues.METHODS:The COX-2 protein and mRNA were investigatedin 27 HCC tissues with adjacent nontumorous tissues,and 5histologically normal liver tissues,using immunohistochemistryand in situ hybridization.RESULTS:The well-differentiated HCC expressed COX-2protein(5.68±1.19)more strongly than moderated HCC(3.43±1.98)and poor differentiated HCC(3.33±1.50)(P<0.05 respectively),adjacent nontumorous tissues(4.93±1.05)and normal liver tissues(3.20±1.92)(P<0.01respectively);More intensive staining of COX-2 in adjacentnontumorous tissues was observed than that in normal livertissues(P<0.05).There was no significant difference amongadjacent nontumorous tissues,moderately differentiated HCCand poorly differentiated HCC(P>0.05).The expression ofCOX-2 mRNA was observed in the cytoplasm of the cells ofHCC and of the hepatocytes in adjacent nontumorous tissuesin which COX-2 protein was positive.CONCLUSION:The overexpression of COX-2 in weld-differentiated HCC suggests that COX-2 may play a role inthe early stages of hepatocarcinogensis.