| PrefaceAny organ disease can invade pleura and result in pleural effusions. Hie differentiation between malignant and nonmalignant pleural effusions are sometimes difficult.As we all know, finding tumor cells in the fluid is the gold standard to diagnose malignant pleural effusions. But, the positive rate is very low . In pleurisies with a negative cytology, the assay of tumor markers in pleual fluid may improve the diagnostic performances. So far, many tumor markers are used. Our objective was to look for the tumor markers with high sensitivity and specificity to serve the clinic.Recently, it has been found that thyroid transcription factor - 1 ( TTF -1) ,which is a new tumor marker, is selectively expressed in thyroid and dien-cephalon. In normal adult lung tissue,TTF -1 was expressed mainly in terminal respiratory unit. In histological specimens, studies have shown that TTF - 1 is highly sensitive and specific in detecting peripherally located carcinoma of lung. This is especially true for pulmonary adenocarcinoma. Thus,TTF -1 is useful in confirming the pulmonary nature of any metastatic adenocarcinoma of unknown origion, provided that the possibility of thyroid primary has been excluded. In our studies, TTF - 1 was performed in the cell block specimens of malignant and nonmalignant pleural effusions with immunohistochemical technique.Recent studies showed that the presence of telomerase activity appears to be correlated with the attainment of immortah'ty of various tumor cells. But,some authors questioned this. They beilelived that telomerase is involved in the patho-genenesis of lung cancer and normal lung tissues. But the expression of telomerase reverse transcriptase(hTERT) in carcinomas has high sensitivity and speci-ficity. In this study, we using TRAP - ELISA assay detected telomersae activity in malignant and benign pleural effusions. TERT expression was examined by immunohistochemical.Materials1. Cytology Sample44 Cytology Samples were chosen finally. There were 29 men and 15 women aged 27 to 88 years. ( nean SD, 60.68 15. 29 )2. ReagentTTF- 1,TERT Histostain, Envision Kit,SABC Kit, Telomerase TRAP -ELISA KitMethods1. According to the final diagnosis achieved and the follow - up evaluation, patients were classified into two groups, malignant and benign pleural effusions.2. Cytological analysis and tumor markers assayPleural fluid was obtained by thoracentesis, rapidly brought to the laboratory. The mixture was then centrifuged. Part of the sediment obatained was used te-lomerase activity assay, the remaining sediment was processed as for a agar -paraffin cell block. Four (mm thick paraffin sections were cut and stained with he-matoxylin and eosin. Immunohistochemical study was carried out on the cell block sections for TTF - 1 and TERT .3. The level of CEA was obtained from the clinical laboratory.4. Statistic analysisQuantitative variables were given as x s. The x test were used to compare qualitative variables. There was statistical difference when p <0.05 and significant statistical difference when p <0. 01. All the Statistic analysis was finished by SPSS11.5 software.Results1. Histophathological featuresObserved under the light microscope,in malignant fluid group,some tumor cells in the HE sections arranged in acini and glands. In metastatic pulmonary adenocarcinomas, the tumor cells showed nuclear staining for TTF - 1. In metastatic expulmonary adenocarcinomas and squamous cell carcinomas, none of them showed the expression of TTF - 1. TERT immunoreactivity showed nuclear Ncyto-plasmic,or membrance staining. The benign pleural effusions were negative for these two tumor markers.2. The results in malignant pleural effusions2.1 The tumor cell detection rate (90.48% ) in the malignant pleura! effusion with agar - paraffin cell block, is much higher than with common smears (52.38%).2.2 During 10 cases of metastatic adenocarcinoma of lung origin,9cases showed nuclear staining for TTF - 1, the positive rate is 90%...
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