title: D2-40: a reliable marker in the diagnosis of pleural mesothelioma.
abstract: OBJECTIVE
  Malignant mesotheliomas of the pleura, peritoneum and pericardium can easily be confused with either metastatic adenocarcinomas or reactive pleural lesions. D2-40, a monoclonal antibody used as a marker for seminomatous germ cell tumours and lymphatic endothelial cells, was recently described in mesothelial cells and type I but not type II pneumocytes.
  
  
  METHODS
  The immunoreactivities of D2-40 in 76 lung carcinomas of different histological types (adenocarcinomas, squamous cell, small cell, and bronchioloalveolar carcinomas) were compared with those of 36 pleural epithelioid and sarcomatoid mesotheliomas and 5 specimens of chronic pleuritis.
  
  
  RESULTS
  While all 18 analysed epithelioid mesotheliomas displayed a strong membranous immunostaining, 18 sarcomatoid mesotheliomas showed no, or a merely faint, cytoplasmic signal, comparable with fibroblasts in chronic pleuritis. Out of all analysed lung carcinomas, 49 showed no immunoreactivity for D2-40 (64%), while the other 27 (36%) showed a focal weak to moderate and only cytoplasmic signal.
  
  
  CONCLUSIONS
  We regard D2-40 as a valid marker in the differential diagnosis of epithelioid mesotheliomas versus pulmonary adenocarcinomas. However, this marker may not properly label sarcomatoid mesotheliomas or distinguish them from reactive pleural lesions.
authors.affiliation: Institute of Pathology, BG Clinics Bergmannsheil, Ruhr University Bochum, Bochum, Germany. annette.mueller@ukmainz.de
authors.forename: Annette M
authors.initials: AM
authors.lastname: Müller
authors.forename: Folker E
authors.initials: FE
authors.lastname: Franke
authors.forename: Klaus-Michael
authors.initials: KM
authors.lastname: Müller
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D000368:Aged; D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000175:diagnosis*; D008297:Male; D008654:Mesothelioma / Q000175:diagnosis*; D008875:Middle Aged; D010995:Pleural Diseases / Q000175:diagnosis; D010997:Pleural Neoplasms / Q000175:diagnosis*
chemical_list: D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D014408:Biomarkers, Tumor; C500987:monoclonal antibody D2-40