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The Diagnostic Role of Claudins in Serous Effusions

Lilach Kleinberg MSc, Arild Holth, Eduard Fridman MD, Ignat Schwartz MD, Ie-Ming Shih MD, PhD, Ben Davidson MD, PhD
DOI: http://dx.doi.org/10.1309/V025QRN3R9CJGNPX 928-937 First published online: 1 June 2007

Abstract

We analyzed the diagnostic role of claudins in effusion cytology in 325 effusions, including 218 ovarian, 49 breast, 15 cervical or endometrial, 10 gastrointestinal, and 8 lung adenocarcinomas and 25 malignant mesotheliomas (MMs). Specimens were analyzed for claudin-1 and claudin-3 expression using immunohistochemical analysis. Ovarian and breast adenocarcinoma were further analyzed for claudin-7 expression. Claudin-1 expression was most frequent in ovarian and cervical or endometrial adenocarcinoma compared with other adenocarcinomas and MMs (P < .001). Claudin-3 expression was comparable in adenocarcinomas of different origin but was absent in MMs (P < .001). Reactive mesothelial cells rarely expressed claudins. Claudin-7 expression was higher in ovarian than in breast adenocarcinoma (P < .001). Our data suggest that expression of claudin-3 or claudin-7 is specific for adenocarcinoma and rules out the diagnosis of cells as mesothelial and that absence of claudin-1 expression excludes ovarian carcinoma as the possible origin of metastatic adenocarcinoma. Claudins may, therefore, be of diagnostic value in effusion cytology.

Key Words:
  • Claudins
  • Effusions
  • Adenocarcinoma
  • Mesothelioma