1. Veterans Affairs Medical Center, Washington, DC 20422, USA
2. Department of Medicine, Uniformed Services University, Bethesda, MD 20814, USA
3. John P. Murtha Cancer Center Research Program, Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD 20817, USA
4. Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817, USA
5. Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
6. Department of Surgery, Walter Reed National Military Medical Center, Bethesda, MD 20814, USA