Correlation between telomerase activity and DNA ploidy in gastric cancer.

Telomerase has been reported to be activated in most immortal cells and human cancers. In the present study, we assessed the correlation between telomerase activity and cellular DNA ploidy level in gastric cancer. Telomerase activity was determined semiquantitatively using the telomeric repeat amplification protocol assay, a polymerase-chain-reaction-based assay, in surgical specimens of primary tumors obtained from 36 patients with gastric cancer. No correlation was observed between telomerase activity and the proliferating cell nuclear antigen labeling index. In contrast, a positive linear correlation was observed between telomerase activity and the DNA index (r = 0.59; p < 0.01). Tumor cells with aneuploid patterns showed higher telomerase activity than those with diploid patterns (27.6+/-5.8 vs. 5.8+/-1.1%; p < 0.01). Telomerase activity of tumors with liver metastases was significantly higher than activity of those without metastases (34.5+/-16.6 vs. 11.8+/-2.4; p < 0.05). There was a trend toward a lower survival rate in 9 patients with a telomerase activity of 20% or higher compared to 27 patients with telomerase activity lower than 20%. These results suggest that the telomerase activity of gastric cancer tissue may reflect the malignant potential of the tumor.