TELOMERASE ACTIVITY IN ORAL LEUKOPLAKIA AND HEAD AND NECK SQUAMOUS-CELL CARCINOMA

The expression of telomerase, a ribonucleoprotein complex, is necessar y to overcome cellular senescence, and it is associated with immortal cells and cancer, However, its role in precancerous lesions such as or al leukoplakias is less known, The purpose of this study is to investi gate the presence of telomerase activity in oral leukoplakia and the r elationship between the enzyme and multistep tumorigenesis. Telomerase activity was detectable in 14 of 16 human head and neck squamous cell carcinomas and 10 of 26 oral leukoplakia tissues. We also showed that the expression of telomerase in the premalignant lesions was associat ed with phenotypic progression, the degree of dysplasia. These results indicate that telomerase is activated frequently during the late stag e of oral premalignancy and may play a crucial role in head and neck s quamous cell carcinogenesis.