1. National Cancer Institute, Rockville, Maryland (M.S.S., P.S.R., E.A.E.)
2. National Cancer Institute, Rockville, Maryland, and University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina (J.Y.I.)
3. National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia (H.I.H., E.J.)