Telomerase activity is frequently found in metaplastic and malignant humannasopharyngeal tissues

Telomerase is a specialized ribonucleoprotein polymerase that directs the s ynthesis of telomere repeats at chromosome ends. Accumulating evidence has indicated that telomerase is stringently repressed in normal human somatic tissues but reactivated in cancers and immortal cells, suggesting that reac tivation of telomerase plays an important role in carcinogenesis. In this s tudy, the status of telomerase activity in diseased human nasopharyngeal le sions was determined by the telomeric repeat amplification protocol (TRAP). Fifty-four patients participated including 17 inflammation or hyperplasia, eight with squamous metaplasia, and 29 with different stages of carcinomas . Telomerase activity was detected in 1 of 17 (5.9%) inflammatory or lympho id hyperplastic tissues, 3 of 8 (37.5%) squamous metaplastic, and 25 of 29 (86.2%) carcinoma tissues. The differences in telomerase expression in thes e groups is statistically significant (P < 0.001). Levels of telomerase act ivity correlated with tumour stage (P = 0.024). These results suggest that telomerase reactivation plays a role in the carcinogenesis of nasopharyngea l cancer. Since telomerase activity is found in the majority of nasopharyng eal cancers and a subset of metaplasia, this enzyme may be served as a refe rence to monitoring the status of abnormal nasopharyngeal tissues. (C) 2000 Cancer Research Campaign.