1. University of Colorado School of Medicine, Aurora, Colorado.
2. Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
3. The Mayo Clinic, Rochester, Minnesota.
4. Boston Medical Center, Boston, Massachusetts.
5. Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
6. University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
7. The University of Siena, Siena, Italy.
8. Massachusetts Eye and Ear Infirmary, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
9. University Health Network, University of Toronto, Toronto, Ontario, Canada.
10. Institute Gustave Roussy and University Paris Sud, Villejuif, France.
11. Oregon Health and Science University, Portland, Oregon.
12. University of Texas M.D. Anderson Cancer Center, Houston, Texas.
13. Duke University School of Medicine, Durham, North Carolina.
14. University of Cincinnati Medical Center, Cincinnati, Ohio.
15. Memorial Sloan Kettering Cancer Center, New York, New York.
16. MedStar Washington Hospital Center, Washington, DC.