title: Use of the monoclonal antibody MOC-31 as an immunomarker for detecting metastatic adenocarcinoma in effusion cytology.
abstract: BACKGROUND
  MOC-31 is an established immunologic marker with which to detect adenocarcinomas. The objective of the current study was to evaluate the use of MOC-31 in the diagnosis of metastatic adenocarcinoma in effusion specimens.
  
  
  METHODS
  The authors evaluated cytologic specimens of effusions/washings in which MOC-31 immunostaining was performed on unstained cell block sections or Papanicolaou-stained cytospin preparations. Membranous staining with or without cytoplasmic staining was considered to be positive. The immunostaining results were correlated with the cytologic diagnoses and clinical follow-up data.
  
  
  RESULTS
  A total of 215 effusions and washings were identified (cell blocks in 162 cases, cytospin preparations in 53 cases, and both in 2 cases in which MOC-31 immunostaining was performed). A total of 94 (44%) of the 215 cases were found to be positive for malignancy, including 87 metastatic adenocarcinomas. Specimens were positive for MOC-31 in 76 (87%; 55 cell blocks and 21 cytospin preparations) of 87 cases of metastatic adenocarcinoma. Eleven cases of metastatic adenocarcinoma were found to be negative for MOC-31 (4 cases from lung tumors, 2 from stomach tumors, 2 from colon tumors, 2 from breast tumors, and 1 from a renal tumor). Minimal and/or focal cytoplasmic staining for MOC-31 was noted in 13% of cases of reactive mesothelial cells/mesothelioma. The sensitivity of MOC-31 for metastatic adenocarcinoma was 89%, the specificity was 100%, the negative predictive value was 92%, and the positive predictive value was 100%.
  
  
  CONCLUSIONS
  MOC-31 alone was found to be highly sensitive for distinguishing reactive mesothelial cells/mesothelioma from metastatic adenocarcinoma in effusion specimens. Interpreting membranous MOC-31 staining as positive can help prevent confusion between reactive mesothelial cells/mesothelioma and metastatic adenocarcinoma. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.
authors: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, USA.
authors: Uma R
authors: UR
authors: Kundu
authors: Savitri
authors: S
authors: Krishnamurthy
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary*; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis*; D002462:Cell Membrane / Q000378:metabolism; D003937:Diagnosis, Differential; D006801:Humans; D007124:Immunoenzyme Techniques; D008654:Mesothelioma / Q000175:diagnosis*; D009369:Neoplasms / Q000473:pathology*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor