Immunohistochemical properties of malignant mesothelioma cells in histologic and cytologic specimens.
ABSTRACT Although there is general agreement that immunohistochemical methods can aid in the pathologic diagnosis of malignant mesothelioma, some studies have produced conflicting results. To obtain comparable and reproducible results, unequivocal malignant mesotheliomas were studied with the biotin-streptavidin-peroxidase complex method in 14 formalin-fixed, paraffin-embedded tissue specimens, 5 ethanol-fixed smear slides and 3 cold acetone-fixed smear slides. The expression of CA-125, epithelial membrane antigen (EMA) and vimentin by malignant epithelial mesothelioma cells was hindered by their poor preservation in formalin fixative. Cytologic specimens fixed in cold acetone were the best type for immunohistochemistry. The majority of malignant epithelial mesothelioma cells in the smear slides fixed in cold acetone were positive for CA-125, EMA, low-molecular-weight cytokeratin and vimentin, but none of them were positive for carcinoembryonic antigen, CA-19-9, epithelial antigen, high-molecular-weight cytokeratin or Leu-M1.
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ABSTRACT: To document that a polyclonal antiserum to calretinin, a 29-kd calcium-binding protein, consistently decorates normal and tumor mesothelial cells in cytologic preparations. Thirty-three archival cytologic specimens from eight patients with histologically confirmed malignant mesothelioma and 13 from patients with metastatic serous effusions were destained and then immunostained with anticalretinin antiserum. For investigation of cell suspensions, four pleural fluids were incubated with anticalretinin antiserum. After cytocentrifugation the specimens were stained in accordance with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method. For electron microscopic examination the cell suspensions were then incubated with gold-labeled antirabbit antibody. The diagnostic sensitivity of this new immunocytochemical approach reached 100% for the eight malignant mesotheliomas investigated. Only 3 of the 13 adenocarcinomas metastatic to the serous membranes included in this study were weakly reactive, accounting for 81% specificity. Binding of anticalretinin antiserum to living mesothelial cells was consistently documented in all four cases investigated. Calretinin is a very useful marker for positive identification of normal and tumor mesothelial cells in serous effusions.Acta cytologica 01/1997; 41(6):1757-61. · 1.56 Impact Factor
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ABSTRACT: Three mesothelioma cell lines (MeET-4, MeET-5, and MeET-6) established from ascitic fluid of F344 rats with spontaneous abdominal mesothelioma have been maintained through at least 60 passages on the DMEM with 10% FBS. Two of original tumours consisted of epithelioid cells growing in a papillary patern, while one (original tumour of MeET-5) had sarcomatous areas composed of spindle-shaped tumour cells. The cell line originating from MeET-5 showed a constantly beiphasic growth pattern during the repetitive subcloning, while the other two lines retained a monophasic growth pattern. Although the growth pattern was different, the tumour cells in all three lines were positive for vimentin and keratin and ultrastructurally showed an abundant distribution of glycogen granules in the cytoplasm and numerous long microvilli on all surface. The modal chromosome number of cell lines varied from 41 to 71, and abnormal chromosomes were frequently seen. All cell lines established formed colonies on semi-solid medium and could be successfully transplanted, growing tumour masses in syngeneic rats and thus indicating their malignant nature. Cell lines grew even on a medium with a low concentration of FBS. The evidence suggests that they may produce growth factors that enable them to survive unfavourable medium conditions.Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 01/1997; 431(4):257-263. DOI:10.1007/s004280050097 · 2.56 Impact Factor
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ABSTRACT: BACKGROUND Malignant effusions are complications of metastatic malignant melanoma (MM). Differential diagnosis often involves distinguishing MM from adenocarcinoma and reactive mesothelial cells. Descriptions in the literature of the morphologic and immunocytochemical (IM) staining characteristics of MM in effusions are sparse. A combination of morphology and immunocytochemistry should yield the most accurate diagnostic results. The MART-1 antigen, a transmembrane protein, is specifically expressed in melanocytes and MM. A recently developed monoclonal antibody to the MART-1 antigen may represent a useful marker for the identification of MM in effusions.METHODS The authors conducted a retrospective review of 32 effusion samples diagnosed as MM. The review consisted of morphologic and IM analyses of the effusion samples with antibodies to MART 1, HMB45, S-100, and cytokeratins (AE1/AE3).IM stains were performed on cell block or cytospin material, depending on availability. In the morphologic review, emphasis was placed on Diff Quik-stained material, due to its enhanced cytoplasmic volume and detail.RESULTSPredominant cytologic features noted were lack of cellular cohesion (in 100% of cases), large eccentric nuclei with prominent nucleoli (in 100%), multinucleation (in 84%), variable cytoplasmic vacuolization (in 75%), pigment (in 72%), and cell-in-cell engulfment (in 47%). All immunoreactive cases with sufficient material stained with at least one of the markers used. Tumor cells were positive with IM stains to MART-1 in 78% of cases, HMB45 in 81%, and S-100 in 81%. Coexpression of MART-1, HMB45, and S-100 was noted in 63% of cases. Of cases that showed expression for only 1 of the 3 antigens, the MART-1 was positive in 1 case, and HMB45 and S-100 were positive in 2 cases each. Three cases showed immunoreactivity for cytokeratins in the melanoma cells.CONCLUSIONS The diagnosis of MM in effusions can be made reliably through a combination of morphologic and IM features. Differential diagnosis often involves distinguishing MM from adenocarcinoma or reactive mesothelial cells. Cytoplasmic vacuolization, multinucleation, prominent nucleoli, and cell-in-cell engulfment are cytologic features common to all three. The lack of IM staining for cytokeratins alone cannot reliably distinguish MM; 11% of cases showed positive staining with this antibody in the melanoma cells. The use of a panel of antibodies increases the accuracy of diagnosing MM. In this study, MART-1 proved a useful adjunct to the HMB45/S-100/cytokeratin panel for the diagnosis of MM in effusions, staining 78% of the immunoreactive cases, with positivity in 1 case that was negative for HMB45 and S-100. Cancer 1997; 81:57-63. © 1997 American Cancer Society.Cancer 02/1997; 81(1):57 - 63. DOI:10.1002/(SICI)1097-0142(19970225)81:1<57::AID-CNCR12>3.0.CO;2-B · 4.90 Impact Factor