Purpose: The ribonucleoprotein enzyme telomerase occurs in immortal lines of mammalian cells including germ cells and most malignancies. The activity of telomerase has potential to emerge as a clinical tumor marker in prognosis or therapeutic options for lung cancer. Telomerase activity has been described in surgical and autopsy specimens of carcinomas but seldom in diagnositc specimens. We prospectively evaluated the feasibility of assessing telomerase activity in diagnostic specimens of thoracic neoplasms. Methods: We assessed telomerase activity in twenty-five bronchoscopic, thoracentesis and fine needle specimens by gel electrophoresis and a PCR ELISA assay using a single blinded study design. The clinical specimens had cytologically confirmed malignancy consisting of 9 small cell carcinomas and 16 non-small cell lung carcinomas including 2 carcinomas metastatic to the thorax. In addition, we noted an absence of significant telomerase activity by the gel electrophoresis technique in four patients with pneumonia, trapped lung or eosinophilic pleuritis. Results: We found telomerase activity by gel electrophoresis in 17 of 25 specimens (68%) including 10 of 13 broncoscopy specimens (77 %), 3 of 8 thoracentesis specimens (38 %) and 4 of 4 fine needle aspirates (100%). When we examined the results by tissue type of carcinoma we found that 6 of 9 small cell carcinomas (68%), and 11 of 16 non-small cell specimens (69%) had gel activity. Six specimens (24%) had relatively high telomerase activities (>0.312 A 450-690) by PCR ELISA assay. These consisted of 2 of 9 small cell (22%) and 4 of 16 non-small cell specimens (25%). Brushings, transbronchial needle aspirates and fine needle aspirates appeared to have greater combined sensitivity (92%) than pleural fluid and lavage specimens (42%). Conclusions: Detection of telomerase activity in thoracic malignancies appears feasible from clinical diagnostic specimens such as bronchoscopy, thoracentesis and fine needle aspirates. The prevalence of telomerase activity by gel electrophoresis was similar in the small cell and non-small cell specimens in this study. Telomerase activity has moderate sensitivity as an indicator of cytologically confirmed malignancy. Clinical Implications: Telomerase activity can be detected in clinical diagnostic specimens from patients with cytologically confirmed lung cancer. Should telomerase prove to be a valuable tumor marker, positivity in diagnostic specimens may obvitate the need for more invasive procedures. Future studies using diagnostic specimens may aid in assessing the value of telomerase activity as a tumor marker.
|Original language||English (US)|
|Issue number||4 SUPPL.|
|State||Published - Oct 1 1998|
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine
- Cardiology and Cardiovascular Medicine