Telomerase Activity in Gastric Adenocarcinomas: Frozen Tissues Versus Methacarn-fixed Paraffin-embedded Tissues

Purpose: Telomerase is an RNA-dependent DNA polymerase that synthesizes TTAGGG telomeric DNA onto chromosome ends to compensate for sequence loss during DNA replication. It has been detected in 8590% of all primary human cancers, implicating that its apparent reactivation in tumors may play a role in the tumorigenic process. The purpose of this study was to evaluate telomerase activity in stomach cancer, and to determine whether methacarn-fixed paraffin-embedded tissues can replace frozen tissue sections for the telomerase (TRAP) assay. Materials and Methods: Frozen and corresponding methacarn- fixed paraffin-embedded tissue samples were obtained from 51 patients with gastric adenocarcinoma and analyzed for telomerase activity by using a TRAPeze ELISA kit. Results: Telomerase activity was detected in 37 (73%) frozen samples, and in 13 (25%) methacarn-fixed paraffin blocks. Telomerase activity was well correlated with depth of invasion (p=.037) and tumor differentiation (p=.022). Conclusion: These data suggest that reactivated telomerase may play a significant role in the tumorigenesis of gastric cancer and may reflect the malignant potential of the tumor. It is noteworthy that methacarn- fixed tissue cannot as yet substitute for the frozen tissue in the TRAP assay.