Telomerase activity as a marker of breast carcinoma in fine-needle aspirated samples

BACKGROUND. Telomerase activity in breast fine-needle aspiration (FNA) samples may have diagnostic utility. The purpose of this study was to compare in FNA samples of breast tumor the diagnostic accuracy as correlated with histologic final diagnosis. METHODS. Fine-needle aspiration samples were obtained from 617 patients with palpable breast tumors. Slide preparation and cytology were performed according to a uniform approach. Extracts derived from 10³ cells from the residual cells in the syringe were used for the telomeric repeat amplification protocol (TRAP) assay. Of the original 617 patients, 220 underwent open biopsy or surgery, and 93 cancers and 127 patients' benign diseases were diagnosed by histologic examination. RESULTS. All 62 tumors that were diagnosed as 'malignant' or 'probably malignant' by FNA cytology were cancerous, and 50 cases (81%) showed detectable telomerase activity. Among 17 'atypical' or 'indeterminate' cases, all 10 tumors with detectable telomerase activity subsequently were diagnosed as breast carcinoma whereas 6 of 7 tumors without telomerase activity were diagnosed as benign. Among the 141 'benign' or 'unsatisfactory' samples, 12 of 21 cases with detectable telomerase activity subsequently were diagnosed as cancer. CONCLUSIONS. The diagnostic accuracy of telomerase activity in FNA samples is considered to be equivalent or slightly higher to that of cytology (86% vs. 70%). Detection of telomerase activity should be considered an alert for false-negative results of FNA cytology and may be useful as a diagnostic marker for breast malignancy, especially in samples cytologically undetermined to be malignant. (C) 2000 American Cancer Society.