AIM:To study the expression and significance of telomeraseactivity and oxidative stress in hepatocellular carcinoma(HCC)with cirrhosis.METHODS:In this study,TRAP-ELISA assay was used todetermine telomerase activity in 21 cases of HCC as well asin 23 cases of hepatic cirrhosis.Malondialdehyde(MDA),glutathione S-transferase(GST)and total anti-oxidativecapacity(T-AOC)were also examined in the same sampleswith human MDA,GST and T-AOC kits.RESULTS:Eighteen of 21 cases of HCC were found to haveincreased telomerase activity,whereas only three of the 23non-cancerous cirrhotic samples were found to have weaktelomerase activity,and the difference was significant(P<0.001).No significant difference in telomerase activitywas detected according to different tumor size,tumor stage,histological grade,HBsAg,contents of albumin,bilirubin,ALT,AFP,r-GT and platelet.There were significantdifferences between HCC and cirrhosis in the expression ofMDA,GST and T-AOC respectively.Telomerase activitycorrelated positively with the content of MDA(P<0.05).CONCLUSION: Telomerase activation is the early event of carcinogenesis, which is not correlated with clinicopathological factors of HCC. The dysfunction of the anti-oxidative system is closely correlated with the progression from cirrhosis to hepatocellular carcinoma. Oxidative stress may contribute partly to telomerase activation. AIM: To study the expression and significance of telomerase activity and oxidative stress in hepatocellular carcinoma (HCC) with cirrhosis. METHODS: In this study, TRAP-ELISA assay was used to determine telomerase activity in 21 cases of HCC as well as in 23 cases of hepatic cirrhosis .Malondialdehyde (MDA), glutathione S-transferase (GST) and total anti-oxidative capacity (T-AOC) were also examined in the same samples with human MDA, GST and T-AOC kits.RESULTS: Eighteen of 21 cases of HCC were found to haveincreased telomerase activity, and only only three of the 23non-cancerous cirrhotic samples were found to have weaktelomerase activity, and the difference was significant (P <0.001) .No significant difference in telomerase activitywas detected according to different tumor size, tumor stage, histological grade, HBsAg, contents of albumin, bilirubin, ALT, AFP, r-GT and platelet. Where were significant differences between HCC and cirrhosis in the expression of MDA, GST and T-AOC respectively.Telomerase activitycorrelated p The effect of the anti-oxidative system is closely correlated with the progression from cirrhosis to MDA (P <0.05) .CONCLUSION: Telomerase activation is the early event of carcinogenesis, which is not correlated with clinicopathological factors of HCC. hepatocellular carcinoma. Oxidative stress may contribute to telomerase activation.