title: Utility of the antibodies CA 19-9, HBME-1, and thrombomodulin in the diagnosis of malignant mesothelioma and adenocarcinoma in cytology.
abstract: BACKGROUND
  The distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in cytologic specimens frequently is difficult, often requiring immunocytochemistry to support the diagnosis. Recent reports have proposed the utilization of antibodies to mesothelial cell clone HBME-1 and thrombomodulin (TM), because they are immunoreactive in MM and less commonly reactive in ACA. Immunoreactivity for the monoclonal antibody CA 19-9 has been observed in many ACAs and reportedly is absent in MM.
  
  
  METHODS
  In this study, immunostaining was performed on formalin fixed, paraffin embedded cell blocks from effusions or fine-needle aspirations using the avidin-biotin-peroxidase method. Thirty-eight MMs and 49 ACAs were tested using antibodies to CA 19-9, HBME-1, and TM.
  
  
  RESULTS
  Anti-CA 19-9 stained only 1 of the 37 cases of MM tested (3%), but stained 24 of the 49 cases of ACA (49%). Anti-HBME-1 stained 34 of 38 cases of MM (89%), and 28 of 43 cases of ACA tested (65%). Anti-TM stained 24 of 36 cases of MM (67%), and 21 of 40 cases of ACA tested (53%).
  
  
  CONCLUSIONS
  CA 19-9 has utility as part of an immunocytochemical panel for distinguishing ACA from MM, because a positive staining reaction would make the diagnosis of MM unlikely. Although HBME-1 and TM can identify MM positively, each frequently is detected in ACA, thus limiting the utility of these antibodies in cytologic specimens.
authors.affiliation: Laboratory of Pathology, Cytopathology Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1500, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Fetsch
authors.forename: A
authors.initials: A
authors.lastname: Abati
authors.forename: Y M
authors.initials: YM
authors.lastname: Hijazi
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology; D000911:Antibodies, Monoclonal / Q000032:analysis*; D000951:Antigens, Neoplasm / Q000276:immunology*; D001707:Biopsy, Needle; D018395:CA-19-9 Antigen / Q000276:immunology*; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D006801:Humans; D007150:Immunohistochemistry; D008654:Mesothelioma / Q000175:diagnosis* / Q000473:pathology; D010996:Pleural Effusion / Q000175:diagnosis; D010997:Pleural Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity; D018180:Thrombomodulin / Q000032:analysis*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D018395:CA-19-9 Antigen; D018180:Thrombomodulin