Telomerase activity (TMA) in tumour and peritumoural tissues in a rat liver cancer model.

PURPOSE To study the levels of telomerase activity (TMA) in tumour and peritumoural tissues in a liver cancer model in rats, and to study the change in TMA expression over time. METHODS Using the telomeric repeated amplification protocol (TRAP), TMA was measured in tumour tissue, peritumoural tissue and normal liver tissue of Walker-256 tumour-bearing rats at 4, 6 and 8 days after tumour implantation. RESULTS TMA at day 4, 6 and 8 was 0.767+/-0.117, 0.768+/-0.118 and 0.774+/-0.111 in tumour tissue, 0.389+/-0.263, 0.492+/-0.253 and 0.584+/-0.239 in peritumoural tissue, and 0.231+/-0.022, 0.229+/-0.022 and 0.233+/-0.021 in normal liver tissue, respectively. TMA in tumour tissue was higher than that in peri-tumour and normal liver tissues at all time points of measurement (P < 0.05). The TMA levels in tumour tissue and normal liver tissue did not show any change over time. TMA level in the peritumoural tissue increased with time; TMA level in animals sacrificed at day 8 was higher than that seen in animals sacrificed at day 4 (P < 0.05). CONCLUSION TMA in walker-256 tumour-bearing rats was higher than that in normal and peritumoural tissues. TMA level in the peritumoural tissue increased with time suggesting that TMA activation in peritumoural tissue may be an important factor promoting tumour growth.