Open Access Research

Cathepsin B: a potential prognostic marker for inflammatory breast cancer

Mohamed A Nouh1†, Mona M Mohamed2*†, Mohamed El-Shinawi3, Mohamed A Shaalan4, Dora Cavallo-Medved5,6, Hussein M Khaled7 and Bonnie F Sloane5,8

  • * Corresponding author: Mona M Mohamed monamos@link.net

  • † Equal contributors

Author Affiliations

1 Department of Pathology, National Cancer Institute, Cairo University, Giza 12613 Egypt

2 Department of Zoology, Faculty of Science, Cairo University, Giza 12613 Egypt

3 Department of General Surgery, Faculty of Medicine, Ain Shams University, Cairo 11566, Egypt

4 Department of Surgery, National Cancer institute, Cairo University, Giza 12613 Egypt

5 Department of Pharmacology, Wayne State University, Detroit, MI 48201, USA

6 Department of Biological Sciences, University of Windsor, Windsor, ON, N9B 3P4 Canada

7 Department of Medical Oncology, National Cancer Institute, Cairo University, Giza 12613 Egypt

8 Barbara Ann Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA

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Journal of Translational Medicine 2011, 9:1 doi:10.1186/1479-5876-9-1

Published: 3 January 2011

Abstract

Background

Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer. In non-IBC, the cysteine protease cathepsin B (CTSB) is known to be involved in cancer progression and invasion; however, very little is known about its role in IBC.

Methods

In this study, we enrolled 23 IBC and 27 non-IBC patients. All patient tissues used for analysis were from untreated patients. Using immunohistochemistry and immunoblotting, we assessed the levels of expression of CTSB in IBC versus non-IBC patient tissues. Previously, we found that CTSB is localized to caveolar membrane microdomains in cancer cell lines including IBC, and therefore, we also examined the expression of caveolin-1 (cav-1), a structural protein of caveolae in IBC versus non-IBC tissues. In addition, we tested the correlation between the expression of CTSB and cav-1 and the number of positive metastatic lymph nodes in both patient groups.

Results

Our results revealed that CTSB and cav-1 were overexpressed in IBC as compared to non-IBC tissues. Moreover, there was a significant positive correlation between the expression of CTSB and the number of positive metastatic lymph nodes in IBC.

Conclusions

CTSB may initiate proteolytic pathways crucial for IBC invasion. Thus, our data demonstrate that CTSB may be a potential prognostic marker for lymph node metastasis in IBC.