Telomerase activity in esophageal carcinoma.
Telomerase is a ribonucleoprotein that synthesizes telomeric DNA. Immortalized and carcinoma cells show no loss of telomere length during cell division. Telomerase activity has been demonstrated in carcinomas of various organs, but not in nonneoplastic tissues. In patients with esophageal carcinoma, no data have been reported concerning the relationship between telomerase activity and clinicopathological findings. Esophageal carcinomas from 31 patients and normal esophageal mucosae from 92 patients were examined. Telomeric Repeat Amplification Protocol assay to detect telomerase activity and Southern blot analysis to examine telomere length were performed. Of the 31 carcinomas, 27 (87%) had detectable telomerase activity. Twenty-one (23%) of the 92 normal esophageal mucosae from autopsied patients also had detectable telomerase activity. There was no difference between stage and outcome and absence or presence of telomerase activity. No difference in terminal restriction fragment (TRF) length was observed between carcinomas with and without telomerase activity. Telomerase activity was demonstrated in a considerable number of normal esophageal mucosae. This suggests the possibility of a high frequency of false positivity if the presence of telomerase activity alone is used as a tumor-specific marker.