Telomerase as a diagnostic and predictive marker in colorectal carcinoma
Abstract:
In a search for molecular markers providing both informative diagnostics of malignant disease, and rational stratification of a therapeutic strategy to achieve optimal response in a given patient, we examined the possibility of using telomerase for this purpose in colorectal cancer. Telomerase, a ribonucleoprotein enzyme complex catalysing synthesis of chromosome ends (telomeres), has been known as an almost universal tumor marker but its predictive value has been found in only a limited number of malignant tumor types. Telomerase activity and expression of its catalytic subunit hTERT was determined in 82 surgical specimens from 41 patients (a sample of tumor tissue and of adjacent morphologically normal tissue was obtained from each patient). Telomerase activity was present in tumor samples from 34 (83%) patients, reaching an average value of 47.6 telomerase units (T.U.), while adjacent tissue specimens were either negative (in 25 (61%) patients), or slightly positive (in 16 (39%) patients) showing 1.5 T.U. on average. In tumor samples from patients without lymphatic node metastases (pN0), an average of 37.1 T.U was found. In contrast, in tumor samples from patients with lymphatic node involvement (pN1 or pN2) the average activity was significantly higher (60.2 T.U., p