Diagnostic Cytopathology. Volume 33, Issue 5 , Pages 320 – 324. Published Online: 20 Oct 2005. [Link]

Yiran Dai, M.D. 1 *, Carlos W.M. Bedrossian, M.D., FIAC 2, Claire W. Michael, M.D. 1

1 Department of Pathology, University of Michigan, Ann Arbor, Michigan

2 Norwegian American Hospital, Chicago, Illinois email: Yiran Dai (daiy@med.umich.edu)

*Correspondence to Yiran Dai, University of Michigan Hospital, Department of Pathology, 1500 E. Medical Center Drive, Room 2G332/Box 0054, Ann Arbor, MI 48105


beta-Catenin is a component of the E-cadherin-catenin cell adhesion complex. It plays an important role in the Wnt/wg pathway, which conveys critical signals for cell proliferation and transformation. The beta-catenin mutation is an important event in the progression of a number of malignancies. In this study, we evaluated the immunohistochemical (IHC) pattern of beta-catenin in a spectrum of mesothelial lesions. Sixty-five formalin-fixed, paraffin-embedded blocks from 54 serous effusions and 11 pleural biopsies were examined. These cases consisted of 33 invasive mesotheliomas, 9 early mesotheliomas (with negative radiologic finding), so-called mesotheliomas in situ, and 23 reactive mesothelial proliferations. A distinct membranous and/or submembranous staining pattern was seen in 23 cases with normal and reactive mesothelium. In contrast, reduced membranous and/or submembranous antibody staining and markedly increased ectopic cytoplasmic and nuclear staining was seen in 26 cases of 33 mesotheliomas. Seven of 9 early mesotheliomas showed increased ectopic cytoplasmic and/or nuclear stain. On the basis of our findings, identification of beta-catenin staining pattern offers a useful marker in the diagnosis of mesothelial lesions and may help identify neoplastic change.