N-cadherin distinguishes pleural mesotheliomas from lung adenocarcinomas -A ThinPrep (R) immunocytochemical study

BAGKGROUND, Cadherins are a family of cell-cell adhesion proteins. The homo typic binding of cadherins is critical for cell sorting and tissue formatio n during organogenesis, Different cadherin subtypes show lineage specific t issue expression, which has been exploited to differentiate histologically similar tumors of varying ontogeny. By applying immunohistochemistry to tis sue sections, the authors have previously documented the utility of N-cadhe rin in distinguishing between pleural mesotheliomas and lung adenocarcinoma s, based on the observation that N-cadherin is expressed in the former dise ase but not in the latter. Because the diagnosis of these diseases is frequ ently rendered on cytologic material rather than tissue biopsies, the autho rs wanted to assess the utility of N-cadherin immunocytochemistry in evalua ting material prepared with ThinPrep(R). METHODS, The authors examined the cytologic material from 12 patients for t he expression of N-cadherin using immunocytochemistry. Four patients had me sotheliomas and eight had adenocarcinomas. ThinPrep slides of the patients' pleural fluid were prepared and stained with the monoclonal antibody 13A9, which is specific for N-cadherin. RESULTS, Of the 12 cases studied, all 4 cases of pleural mesothelioma expre ssed N-cadherin in a specific cell-cell membrane location, and all 8 cases of lung adenocarcinoma were negative for N-cadherin. CONCLUSIONS. These results show that the N-cadherin specific antibody 13A9 is a suitable marker in material prepared with ThinPrep(R) for the differen tiation of pleural mesotheliomas from lung adenocarcinomas. This antibody s hould be included in the diagnostic immunocytochemical panel for evaluation of these malignancies. (C) 1999 American Cancer Society.