1. Massachusetts General Hospital , Boston, Massachusetts , USA
2. Dana-Farber Cancer Institute , Boston, Massachusetts , USA
3. Harvard Medical School , Boston, Massachusetts , USA
4. Washington University in Saint Louis , Saint Louis, Missouri , USA
5. Stanford University , Stanford, California , USA
6. SRI International , Menlo Park, California , USA
7. Johns Hopkins University School of Medicine , Baltimore, Maryland , USA
8. University of Nebraska Medical Center , Omaha, Nebraska , USA
9. University of California , Los Angeles, California , USA
10. McGill University , Montreal, Quebec , Canada
11. Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland , USA
12. Division of AIDS Research, National Institute of Mental Health, National Institutes of Health , Bethesda, Maryland , USA
13. Missouri Institute of Mental Health, University of Missouri , Saint Louis, Missouri , USA