Immunohistochemical analysis still has a limited role in the diagnosis of malignant mesothelioma - A study of thirteen antibodies

To identify the most accurate and useful panel to diagnose mesothelioma, we immunostained sections from 112 mesotheliomas, 18 adenocarcinomas, and I I reactive pleural specimens with 13 antibodies. Positive results for mesoth eliomas, adenocarcinomas, and reactive pleura, respectively, were CAM5.2, 1 11, 18, and 11; vimentin, 30, 3, and 3; HBME-1, 75, 10, and 8; thrombomodul in, 31, 2, and 2; calretinin, 43, 6, and 11; and CD44H, 68, 10, and 4. Posi tive results for adenocarcinoma markers in mesotheliomas and adenocarcinoma s, respectively, were carcinoembryonic antigen, 1 and 15; LeuM1, 7 and 9; a nd Ber-EP4, 5 and 12. All reactive pleura were negative. Positive results f or markers to help distinguish mesothelioma from reactive pleura in mesothe liomas, adenocarcinomas, and reactive pleura, respectively, were epithelial membrane antigen, 76, 17, and 6; p53, 78, 16, and 9; P-170 glycoprotein, 3 7, 4, and 2; and platelet-derived growth factor receptor beta, 31, 1, and 2. The differential diagnosis of mesothelioma from adenocarcinoma is based on negative markers. Individual mesothelial markers are of low sensitivity and specificity for mesothelioma. However, diagnostic accuracy is improved by the use of antibody panels. To date there are no antibodies that help disti nguish mesothelioma from reactive pleura.