Telomerase activity in oral leukoplakia and head and neck squamous cell carcinoma.

The expression of telomerase, a ribonucleoprotein complex, is necessary to overcome cellular senescence, and it is associated with immortal cells and cancer. However, its role in precancerous lesions such as oral leukoplakias is less known. The purpose of this study is to investigate the presence of telomerase activity in oral leukoplakia and the relationship 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 associated with phenotypic progression, the degree of dysplasia. These results indicate that telomerase is activated frequently during the late stage of oral premalignancy and may play a crucial role in head and neck squamous cell carcinogenesis.