Telomerase activity in pleural effusions: Diagnostic significance

Purpose: To determine the diagnostic value of pleural fluid telomerase activity in distinguishing a malignant from a nonmalignant pleural effusion in a cohort of patients undergoing thoracentesis. Patients and Methods: Using ct polymerase chain reaction (PCR)-based assay, telomerase activity was examined in the pleural fluid cells obtained from 144 consecutive, unselected patients. According to the final diagnosis achieved, these patients were classified into three groups: group I consisted of 70 malignant pleural effusions diagnosed by either fluid cytology or pleural biopsy, group II consisted of 52 nonmalignant pleural effusions, and another 22 samples were categorized to be suspicious malignant pleural effusions (group III) due to inconclusive results in effusion cytology and percutaneous pleural biopsy, but were strongly suspicious in clinical settings. Results: The presence of telomerase activity was observed in 64 of 70 samples in group I (91.4%), three of 52 samples in group II (5.8%), and 20 of 22 samples in group III. All three nonmalignant, telomerase-positive pleural effusion samples in group II were obtained from patients with tuberculosis. As a diagnostic criterion for malignant pleural effusion in group I and group II patients, positive telomerase activity had a sensitivity of 91.4%, a specificity of 94.2%, and a positive and negative predictive value of 0.96 and 0.89, respectively. Conclusion: Our results indicate that the detection of telomerase activity may be a useful adjunct to cytopathologic methods in the diagnosis of malignant pleural effusions. (C) 1998 by American Society of Clinical Oncology.