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World J Clin Oncol. Feb 10, 2013; 4(1): 1-3
Published online Feb 10, 2013. doi: 10.5306/wjco.v4.i1.1
Cathepsin D: Autoantibody profiling as a diagnostic marker for cancers
Martin Fusek, Vaclav Vetvicka
Vaclav Vetvicka, Department of Pathology, University of Louisville, Louisville, KY 40202, United States
Martin Fusek, Department of Biochemistry and Microbiology, Institute of Chemical Technology, 166 28 Prague, Czech Republic
Author contributions: The two authors contributed equally to this work.
Correspondence to: Vaclav Vetvicka, PhD, Professor of Pathology, Department of Pathology, University of Louisville, 511 S Floyd, Louisville, KY 40202, United States. vaclav.vetvicka@louisville.edu
Telephone: +1-502-8521612 Fax: +1-502-8521177
Received: October 15, 2012
Revised: December 4, 2012
Accepted: December 15, 2012
Published online: February 10, 2013

Current diagnostic assays for many cancers are antigen-based and rely on the detection of circulating proteins that are associated with a particular cancer. These assays depend on the expression, synthesis, and release of specific proteins by cells (e.g., tumor cells) through either active secretion or shedding, or as a consequence of cell death (either necrosis or apoptosis). As such, these antigenic proteins must “escape” the primary site of disease, saturate the antigen-processing capacity of the individual’s immune components, gain access to the circulation, and reach a sufficient steady-state concentration to be detected by enzyme- or radiolabel-based immunoassays. These events usually occur after the initial establishment of disease. Thus, and despite the fact that certain specific antigenic epitopes exhibit common recognition among patients with the same tumor types, the use of these antigen-based cancer assays has not been widely accepted in clinical practice, and many individual countries differ in the use of these potential diagnostic factors. Lately, an increasing number of studies demonstrated that procathepsin D secreted from cancer cells, acts as a mitogen on cancer cells and stimulates their pro-invasive and pro-metastatic properties. In this report, we focused on the possibility to use anti-procathepsin D autoantibodies as a diagnostic and/or predictive marker for cancers.

Keywords: Cathepsin D, Procathepsin D, Autoantibodies, Diagnosis, Marker