BACKGROUND: Telomerase activity is associated with many malignancies, including head and neck cancer. The use of telomerase activity as a diagnostic and prognostic marker of head and neck cancer development was examined and compared with standard histological analysis. PATIENTS AND METHODS: Telomerase activity was determined using quantitative dual-colour real-time TRAP (telomeric repeat amplification protocol). In each of 58 patients, a sample of tumour tissue, adjacent mucosa and normal muscle was collected. RESULTS: Telomerase activation was observed in 88% of tumour tissues and 34% of tumour-adjacent mucosa samples. No telomerase activity was detected in normal muscle tissues. Telomerase activity correlated with tumour grade, with an average of 4.6 telomerase units (T.U.) in well-differentiated, 8.3 T.U. in moderately-differentiated and 20 T.U. in poorly differentiated tumours. Relapse occurred in 13 patients and no telomerase activity was detected in 3 recurrent tumours. CONCLUSION: Telomerase activity may be used as an objective parameter inversely related to tumour differentiation. Prognosis in telomerase-negative tumours is worse than that of the telomerase-positive group.

Department of Functional Genomics and Proteomics Institute of Experimental Biology Faculty of Science Masaryk University CZ 62500 Brno Czech Republic

Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes

Hypomethylating drugs efficiently decrease cytosine methylation in telomeric DNA and activate telomerase without affecting telomere lengths in tobacco cells