RESUMEN
The aim of the present study was to investigate the diagnostic efficacy of telomerase enzyme activity for discrimination of malignant and non malignant pleural effusion and to compare the results with those of cytological examination. Pleural effusions were collected from 40 patients. 31 of them had malignancy, either primary or secondary, confirmed by histopatholological examination and the other 9 patients had non-malignant pleural effusion. Of 31 patients with malignant pleural effusion 10 sputum samples were collected to be subjected to telomerase activity, as a probable early diagnostic marker of lung cancer. 9 sputum samples were collected from control patients. Telomerase activity was determined with telomerase catalytic subunit hTERT-mRNA Gene expression assay using [QRT multiplex real-time PCR]. Telomerase activity was detected in 27/31 [87.1%] and in 2/9 [22.2%] samples from the malignant and non malignant pleural effusion groups, respectively. The X +/- SD of hTERT were significantly different between the malignant and non malignant effusion groups. In sputum samples, telomerase activity was detected in 8/10 [80%] of malignant samples. The X +/- SD of sputum hTERT were also significantly different between the malignant and non malignant groups. The sensitivity and specificity of pleural cytology were 67.8% and 100%, while, the sensitivity and specificity of telomerase activity were [87.1%] and [78%] respectively. Generally, the diagnostic values of cytology were lower than those of hTERT in pleural effusion. However, the sensitivity and specificity rates of pleural cytological examination when combined with telomerase activity were [90.3%] and [100%]. Also, the sensitivity and specificity of sputum cytological examination when combined with telomerase activity were [80%] and [100%], while the sensitivity and specificity of sputum cytology alone were 70% and 100% and those of telomerase activity alone in sputum were [80%] and [78%]. It could be concluded that telomerase activity is a highly sensitive diagnostic biomarker for malignancy and may be used as an adjunct to cytological findings in determining pleural effusion and lung malignancies