ABSTRACT
PURPOSE: This study was designed to determine whether telomerase activity measured in samples of tumoral tissue, transitional mucosa, and normal mucosa from patients with sporadic colorectal cancer is a prognostic factor for recurrence and overall survival. METHODS: Telomerase activity was determined by fluorescence-based telomeric repeat amplification in tissue samples from 108 patients with sporadic colorectal cancer. A telomerase index was determined by using the formula log (telomerase activity of cancer tissue - telomerase activity of normal mucosa). RESULTS: Mean telomerase activity in tumoral tissue was 11.49 (total product generated), in transitional mucosa it was 1.51, and in normal mucosa it was 1.09 (P < 0.001). Telomerase activity and telomerase index were not correlated with clinicopathologic factors. Rectal cancer patients' recurrence-free survival was related to N classification (P = 0.004) and to tumor-node-metastases stage classification (P = 0.023) and telomerase index 0.85 (P = 0.023). Overall survival was associated with N classification (positive/negative) and telomerase index (0.85; P = 0.018 and P = 0.011, respectively). CONCLUSIONS: Measurement of telomerase activity has a diagnostic value in colorectal patients. In rectal cancer, telomerase index is an independent prognostic factor for disease progression. A telomerase index
