Immunophenotypings of malignant epithelial mesothelioma and their roles in the differential diagnosis.

To investigate the immunophenotypings of malignant epithelial mesothelioma (MEM), and to seek the valuable markers in distinguishing peritoneal MEM from peritoneal metastatic ovarian adenocarcinoma (OA) and colorectal adenocarcinoma (CA), immunohistochemical SP method was used to detect expressions of HBME-1, E-cadherin, CA19-9, MOC-31 and CK7 in paraffin-embedded tissues of 18 cases of MEM, 20 OA and 20 CA. The results showed that there was a significant difference in the expressions of E-cadherin, CA19-9 and MOC-31 between MEM and OA group (P<0.05). Similarly, the difference in the expression of HBME-1, E-cadherin, CA19-9, MOC-31 and CK7 between MEM and CA groups is significant (P<0.05). These results indicate that HBME-1 could be used as a positive marker in distinguishing MEM from CA. E-cadherin, CA19-9 and MOC-31 are considered to be useful negative markers in diagnostic distinction between MEM and metastatic adenocarcinomas, including OA and CA. CK7 is the best positive marker in distinguishing MEM from CA, but this marker appears to be valueless in discriminating MEM from OA.