Telomerase activity in stage II colorectal carcinoma

Telomerase is a ribonucleoprotein polymerase that adds telomeric repeats to chromosome ends. This enzyme is deficient in the majority of normal somatic cells, but often is reactivated during tumorigenesis. In the current study, the authors examined telomerase activity in human American Joint Committee on Cancer Stage II colorectal carcinomas and correlated it with traditional prognostic indicators and disease outcome.

The telomerase repeat amplification protocol (TRAP) was employed to determine telomerase activity in 122 surgical specimens (from 77 male and 45 female patients) of human Stage II colorectal carcinoma. The primary site of the tumor was the colon in 52 cases and the rectum in 70 cases. Telomerase activity was correlated with traditional prognostic indicators such as gender, age, T classification, tumor size, tumor grade, and disease outcome (overall survival and disease-free survival). The Median follow-up for patients who still were alive was 5.8 years.

Telomerase activity was detected in 80% of the tumors (98 of 122 tumors). Telomerase-positive patients differed from telomerase-negative patients in that they tended to be female (41% vs. 21%; P = 0.1), presented with primary tumors of the colon more frequently (49% vs. 17%; P = 0.01), and had a higher T classification (T(4)) (62% vs. 38%; P = 0.04). Univariate and multivariate analyses demonstrated a correlation between telomerase activity and disease-free survival (P = 0.05).

Although a large percentage of Stage II colorectal carcinoma samples were positive for telomerase activity, the prognosis for patients with telomerase-negative tumors was found to be worse than that for patients with telomerase-positive tumors.