The role of D2-40, and podoplanin in differentiating mesotheliomas from primary adenocarcinomas of the lung and metastatic carcinomas of the pleura

Abstract

Objective: The aim of this study was to assess the diagnostic and differential significance of two recently introduced positive mesothelial markers, namely podoplanin and D2-40. Material and Method: The study group included a total of 55 cases: 11 cases of malignant mesothelioma and equal number of cases (n:11) of primary lung adenocarcinoma, bronchioloalveolar carcinoma, metastatic carcinoma of the pleura and mesothelial proliferation. D2-40, podoplanin, calretinin, cytokeratin 5/6, carcinoembryonic antigen, epithelial specific antigen (MOC-31) were immunohistochemically studied in all cases. The extent of staining was graded between 1+ and 4+. Results: While the 7 (63.6%) of the mesotheliomas and 10 of the mesothelial proliferations (90.9%) stained positive with D2-40, no positive staining was noted in primary lung adenocarcinoma, bronchioloalveolar carcinoma, metastatic carcinoma of the pleura. 9 of the mesotheliomas (81.8%) and 10 of the mesothelial proliferations (90.9%) were positive with podoplanin whereas no positive staining was observed in the other groups. Eight of the primary lung adenocarcinomas (72.7%), seven of the bronchioloalveolar carcinomas (63.6%), and eight of the metastatic carcinomas of the pleura (72.7%) were positive for MOC-31 while only one of the mesotheliomas (9%) was positive and no mesothelial proliferation cases were positive. The specificity of podoplanin, D2-40, calretinin and cytokeratin 5/6 for mesothelioma was 100% and their sensitivity was 81.8%, 63.6%, 81.8% and 54.5%, respectively. The highest sensitivity, (i.e. 100% sensitivity) for mesothelioma was observed with the D2-40, podoplanin, and calretinin combination. Conclusion: D2-40 and Podoplanin were effective in differentiating malignant mesothelioma from primary lung adenocarcinomas, bronchioloalveolar carcinoma and metastatic carcinomas of the pleura. However, since they may not yield precise results it was therefore concluded that a panel combined with positive and negative mesothelial markers including these two markers will lead to more accurate results.