Telomerase activity

Abstract

BACKGROUND The purpose of the current study was to determine telomerase activity as a sensitive biomarker for the detection of malignant cells in fine-needle aspiration (FNA) specimens. METHODS FNA specimens with parallel samples of fresh tumor tissue were obtained from surgical specimens after surgical excision. Using a polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) assay, telomerase activity was determined systematically in FNA specimens (n = 21) and corresponding available tissue biopsy specimens (n = 16) containing malignant cells. In addition to a case of myelolipoma, normal counterparts for 3 of 16 cancer cases, including both biopsy and FNA specimens, also were available 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 cecum). In contrast, specimens from three normal tissue biopsies and FNA specimens of normal tissue adjacent to the malignant lesions, as well as the myelolipoma, exhibited no telomerase activity. It is interesting to note that both tissue biopsy specimens and FNA specimens from a patient with high grade sarcoma were negative for telomerase activity. The examination of hematoxylin and eosin-stained adjacent tissue biopsy sections or FNA smears revealed 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 specimens in 15 of the 16 patients, indicating a 94% concordance rate (95% confidence interval, 70%, 98%). CONCLUSIONS The results of the current study clearly suggest that the telomerase activity in FNA specimens was comparable to that of their corresponding biopsy specimens, and that this activity was associated with the presence of malignant cells. The TRAP assay has potential for use in the detection of malignant cells in FNA specimens, particularly cases in which the cytology is not characteristically malignant and/or is present in insufficient numbers. Cancer (Cancer Cytopathol) 1999;87:210–5. © 1999 American Cancer Society.