Quantitative analysis of telomerase activity: a potential diagnostic tool for colorectal carcinoma

We describe the results of the application of the nonradioactive F-TRAP (fluorescence-based telomeric repeat amplification protocol) assay for the diagnosis of colorectal carcinoma(s). We also investigated whether the level of telomerase activity in colorectal carcinoma can be distinguished from that in normal colorectal tissue or benign colorectal tumors, in which the presence of telomerase activity has also been demonstrated. In addition, we also investigated whether it could be a potential tumor progression marker.

The F-TRAP assay was performed, using biopsy specimens obtained from colonoscopic examinations, including 20 colorectal carcinoma, 10 tubular adenoma and 20 adjacent colorectal normal tissue specimens. In 15 carcinoma cases, the correlation between telomerase activity level and clinicopathological parameters was analyzed.

The results showed that the level of telomerase activity in colorectal carcinomas (88.71 +/- 92.1 units; mean +/- SD) was much higher than that in normal colorectal tissues (3.34 +/- 8.57 units) or adenomas (7.8 +/- 10.27 units). By quantifying the level of telomerase activity using the F-TRAP assay, colorectal carcinomas can be distinguished from normal colorectal tissue or colorectal benign tumors. However, no significant correlation was observed between telomerase activity levels and clinicopathological parameters such as depth of tumor invasion, lymphatic and/or venous involvement, and regional lymph node metastasis and Dukes' stage.

Quantitative analysis of the level of telomerase activity using the F-TRAP assay provides a useful diagnostic tool for colorectal carcinoma, but it would not be useful as a tumor progression marker.