57. Clinical significance of telomerase activity in gastric carcinoma and peritoneal dissemination

Objective: Telomerase activity (TA) is responsible for telomere maintenance and is believed to be crucial in most immortal cells and cancer cells; however, its clinicopathological significance in gastric cancer remains to be clarified. In this study, we investigate the telomerase in gastric cancer and its peritoneal washings, combing with cytology and Enzyme immunoassay for the CA125 in peritoneal washings, we are trying to reveal the relationship between the telomerase activity and the development of gastric cancer, and the relationship between the telomerase activity and the peritoneal dissemination.
Methods: Telomeric repeated amplification protocol (TRAP)- enzyme-linked immunosorbent assay (ELISA) was performed on peritoneal lavage fluid collected from 46 gastric carcinoma patients and 14 gastric ulcer patients. Exfoliative cytologic analysis was used for comparison.
Results: The positivity rate of telomerase activity in peritoneal lavage fluid collected from PT3 to PT4 gastric carcinoma were 55.6% and 99.3%, respectively; from surface area of serosal involvement 0, ≤10 cm², 10-20 cm²; and ≥20 cm² were 5.3%, 25.0%, 76.9%, and 100%, respectively. Meanwhile the positive rates of exfoliative cytology in peritoneal lavage fluid collected PT3 and PT4 gastric carcinoma were 22.2% and 61.5%; from surface area of serosal involvement 0, ≤10 cm², 10-20 cm²; and ≥ 20 cm² were 0%, 0%, 38.5% and 70%. The positive rate of TRAPELISA was significantly higher than that of exfoliate cytology (47.8% vs. 26.1%, P<0.05).
Conclusions: The TRAP assay for telomerase activity is a useful adjunct for cytologic method in the diagnosis of peritoneal micrometastasis. There is positive correlation between telomerase activity of peritoneal lavage fluid and peritoneal dissemination of gastric cancinoma.