Quantification of telomerase activity in human liver tissues by fluorescence-based TRAP analysis

Normal human liver cells have a limited proliferactive capacity, but immortalized cells prevent the shortening of the end of chromosomes by the expression of telomerase, the enzyme that elongates telomeric DNA. In view of the wide variety of different methods of detecting telomerase activity, a quantitative standard system is needed. Therefore, we constructed a quantitative system based on a TRAP-eze(TM) (ONCOR(R)) and the Fluorescence-based TRAP assay, and we quantified telomerase activity in normal liver tissues, livers with chronic liver disease, and livers with hepatocellular carcinoma (HCC). With this method, the average quantitative telomerase activity in chronic hepatitis tissues (n = 17) was 7.97 with a standard error of 6.07, in liver cirrhosis tissues (n = 19) it was 10.82 with a standard error of 5.87, and in HCC tissues (n = 20) it was 46.87 with a standard error of 4.55. In all normal tissues (n = 3), telomerase activity was not detected. No difference between chronic hepatitis tissues and liver cirrhosis tissues was detected. But, the difference was highly significant (P < 0.001) between normal liver tissues and other liver tissues, between chronic hepatitis tissues and HCC tissues, and between liver cirrhosis tissues and HCC tissues. The possibility is great that chronic hepatitis tissues and liver cirrhosis tissues become HCC when telomerase activity is high. Namely, patients with high telomerase activity in chronic hepatitis and liver cirrhosis may be at the risk of developing HCC. This study showed the assay of telomerase activity in chronic hepatitis tissues and liver cirrhosis tissues could play a useful role in screening HCC. (C) 1997 Elsevier Science Ireland Ltd.