Clinical significance of telomerase activity in hepatocellular carcinoma

Telomerase is a ribonucleoprotein enzyme that elongates telomeric DNA. It has been reported that most immortal cell lines express telomerase, whereas in adult normal tissues telomerase activity is not detected. So, in malignant tumors telomerase is thought to be activated to maintain their immortality. In this study, we examined telomerase activity in 12 cases of hepatocellular carcinoma (HCC) with the use of PCR-based assay and analyzed the relationship of telomerase activity to clinicopathological features. In 11 of 12 HCC nodules telomerase activity was detected, of which 9 cases showed strong activity. There was no significant correlation between telomerase activity and clinicopathological features of HCC. Telomerase activity among 6 well-differentiated HCCs was strong in 3 (50%), weak in 2 (33%), and undetected in 1 (17%). All of 6 moderately-differentiated HCCs (100%), however, showed strong activity. As regards tumor size, 4 of 5 HCCs (80%) less than 3 cm in diameter showed strong telomerase activity. On the other hand, weak telomerase activity was detected in only 2 of 12 (17%) noncancerous liver tissues surrounding HCC nodules. The assay of telomerase activity may be a useful diagnostic marker of HCC regardless of tumor size, and the activity may be expressed even at early stage.