[1] Fred Hutchinson Canc Res Ctr, Publ Hlth Sci Div, Seattle, WA 98109 USA
[2] Fred Hutchinson Canc Res Ctr, Clin Res Div, Seattle, WA 98109 USA
[3] Univ Washington, Dept Pediat, Seattle, WA 98195 USA
[4] Univ Washington, Dept Family Med, Seattle, WA 98195 USA
[5] St Jude Childrens Res Hosp, Dept Oncol, 332 N Lauderdale St, Memphis, TN 38105 USA
[6] St Jude Childrens Res Hosp, Dept Epidemiol & Canc Control, 332 N Lauderdale St, Memphis, TN 38105 USA
[7] Univ Toronto, Hosp Sick Children, Dept Pediat, Toronto, ON, Canada
[8] Mem Sloan Kettering Canc Ctr, Dept Med, 1275 York Ave, New York, NY 10021 USA
[9] Duke Univ, Dept Med, Durham, NC USA