Telomerase is a highly sensitive and specific molecular marker in fine-needle aspirates of breast lesions

Purpose: Telomerase has been detected in a majority of human malignant tumo rs, making telomerase activity (TA) one key difference between mortal and i mmortal cells. In this study, we evaluated in blind-trial fashion the assoc iation of TA with cytologic and final clinical/pathologic diagnosis in fine -needle aspirates (FNAs) of breast lesions, Materials and Methods: In 172 FNAs, including 80 samples that were cytologi cally malignant, 18 that were atypical but not diagnostic for malignancy, a nd 74 that were cytologically benign, TA was determined by a modified nonra dioactive telomeric repeat amplification protocol (TRAP) assay. Final diagn osis was made by pathologic examination of follow-up surgical material avai lable for all the cytologically malignant samples, a majority of the cytolo gically atypical samples, and a portion of the cytologically benign samples . Results: TA was detected in 85 of 172 samples. Comparison of the cytologic and histologic diagnoses with TA showed that 80 of 87 samples from patients with breast cancer were telomerase-positive, resulting in a sensitivity of 92%, TA was found in four of five FNAs from carcinomas that were considere d cytologically atypical but not diagnostic for malignancy. Eighty of 85 sa mples from patients with benign breast lesions were telomerase-negative, re vealing a specificity of 94%, The five positive cases in this group were al l fibroadenomas with low TA, Among the 18 cases with a cytologic diagnosis of atypia, there was a strong positive relationship between TRAP findings a nd histologic diagnosis. Conclusion: The detection of TA in FNAs of breast lesions is a highly sensi tive and specific marker of malignancy and may be used as an adjunct in cas es with an equivocal cytologic diagnosis, (C) 1999 by American Society of C linical Oncology.