Telomerase activity in thyroid malignancy

Telomerase activity seems to play a role in the development and pathogenesi s of thyroid carcinoma. Its incidence of expression and its application as a tumor marker remain to be elucidated. Thyroid tissues obtained during thy roidectomy from 1996-1998 were rapidly frozen and stored at -80 degrees C u ntil processed. Telomerase activity was determined using telomeric repeat a mplification protocol (TRAP). Histology of the tissue examined (67 benign a nd 59 malignant) was reviewed. Telomerase activity was detected in 15 of 52 papillary carcinomas (29%); 1 of 1 thyroid lymphoma (100%); 1 of 2 anaplas tic carcinomas (50%); and 2 of 16 lymphocytic thyroiditis specimens (13%). Telomerase activity was not detectable in 35 normal thyroid, 9 follicular a denoma, 7 nodular hyperplasia, 2 follicular carcinoma, and 2 medullary carc inoma. Lymphocytic thyroiditis was detected in 8 of 37 (22%) apparently nor mal thyroid tissues adjacent to papillary thyroid carcinoma and telomerase activity was present in 2 of these 8 specimens (25%). In conclusion, telome rase does not appear to be frequently activated in papillary thyroid carcin oma. The association of lymphocytic thyroiditis with papillary thyroid carc inoma may limit its clinical usefulness as a tumor marker.