Table of Contents
International Journal of Molecular Imaging
Volume 2011 (2011), Article ID 834515, 9 pages
http://dx.doi.org/10.1155/2011/834515
Research Article

CA19-9 as a Potential Target for Radiolabeled Antibody-Based Positron Emission Tomography of Pancreas Cancer

1Department of Surgery, UCLA, 10833 LeConte Avenue, Rm 54-140, Los Angeles, CA 90095, USA
2Department of Surgery, Veterans Affairs Greater Los Angeles, Health Care Center, Los Angeles, CA 90073, USA
3Department of Molecular and Medical Pharmacology, Crump Institute for Molecular Imaging, Los Angeles, CA 90095, USA

Received 5 May 2011; Accepted 3 July 2011

Academic Editor: Ronald L. Van Heertum

Copyright © 2011 Mark D. Girgis et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Introduction. Sensitive and specific imaging of pancreas cancer are necessary for accurate diagnosis, staging, and treatment. The vast majority of pancreas cancers express the carbohydrate tumor antigen CA19-9. The goal of this study was to determine the potential to target CA19-9 with a radiolabeled anti-CA19-9 antibody for imaging pancreas cancer. Methods. CA19-9 was quantified using flow cytometry on human pancreas cancer cell lines. An intact murine anti-CA19-9 monoclonal antibody was labeled with a positron emitting radionuclide (Iodine-124) and injected into mice harboring antigen positive and negative xenografts. MicroPET/CT were performed at successive time intervals (72 hours, 96 hours, 120 hours) after injection. Radioactivity was measured in blood and tumor to provide objective confirmation of the images. Results. Antigen expression by flow cytometry revealed approximately 1.3×106 CA19-9 antigens for the positive cell line and no expression in the negative cell line. Pancreas xenograft imaging with Iodine-124-labeled anti-CA19-9 mAb demonstrated an average tumor to blood ratio of 5 and positive to negative tumor ratio of 20. Conclusion. We show in vivo targeting of our antigen positive xenograft with a radiolabeled anti-CA19-9 antibody. These data demonstrate the potential to achieve anti-CA19-9 antibody based positron emission tomography of pancreas cancer.