AIM:To study the telomerase expression in gastric carcinoma and its clinical implications.METHODS:Telomerase activity was examined in gastric cancer and corresponding normal tissues using a modified TRAP (telomeric repeat amplify-cation protocol) assay (TRAP-eze) in tissue samples from 94 gastric carcinomas and 58 normal tissues, 12 gastric adenomas and 9 gastric ulcer lesions.RESULTS:Telomerase activity was present in 81 of the 94 (86.2%) gastric cancer tissues, whereas no telomerase activity was detected in any normal tissues.The incidence of telomerase activity in gastric cancer tissues was unrelated to the tumor diameter, histological grade, tumor invasion in depth, lymph node metastasis and TNM stage.CONCLUSION:Telomerase plays an important role in carcinogenesis and progression of gastric cancer, and it is suggested to be a useful tumor marker.