Telomerase activity - Comparison between fine-needle aspiration and biopsyspecimens for the detection of tumor cells

BACKGROUND. The purpose of the current study was to determine telomerase ac tivity as a sensitive biomarker for the detection of malignant cells in fin e-needle aspiration (FNA) specimens. METHODS. FNA specimens with parallel samples of fresh tumor tissue were obt ained from surgical specimens after surgical excision. Using a polymerase c hain reaction-based telomeric repeat amplification protocol (TRAP) assay, t elomerase activity was determined systematically in FNA specimens (n = 21) and corresponding available tissue biopsy specimens (n = 16) containing mal ignant cells. In addition to a case of myelolipoma, normal counterparts for 3 of 16 cancer cases, including both biopsy and FNA specimens, also were a vailable for the determination of telomerase activity. RESULTS. Telomerase activity was observed in 14 of 16 of the FNA specimens (88%) and 15 of 16 of the corresponding biopsy specimens (94%). Telomerase activity was detected in both the biopsy specimen and the corresponding FNA specimen, with one exception (a case of mucinous adenocarcinoma of the cec um). In contrast, specimens from three normal tissue biopsies and FNA speci mens of normal tissue adjacent to the malignant lesions, as well as the mye lolipoma, exhibited no telomerase activity. It is interesting to note that both tissue biopsy specimens and FNA specimens from a patient with high gra de sarcoma were negative for telomerase activity. The examination of hemato xylin and eosin-stained adjacent tissue biopsy sections or FNA smears revea led similar low populations of lymphocytes, including those cases that were negative for telomerase activity. There was agreement in the detection of telomerase activity between tissue biopsies and their corresponding FNA spe cimens in 15 of the 16 patients, indicating a 94% concordance rate (95% con fidence interval, 70%, 98%). CONCLUSIONS. The results of the current study clearly suggest that the telo merase activity in FNA specimens was comparable to that of their correspond ing biopsy specimens, and that this activity was associated with the presen ce of malignant cells. The TRAP assay has potential for use in the detectio n of malignant cells in FNA specimens, particularly cases in which the cyto logy is not characteristically malignant and/or is present in insufficient numbers. (C) 1999 American Cancer Society.