[1] Univ Utah, Huntsman Canc Inst, Dept Populat Hlth Sci, Salt Lake City, UT USA
[2] Seattle Childrens Hosp, Div Pediat Hematol Oncol, Seattle, WA USA
[3] Univ Washington, Dept Pediat, Sch Med, Seattle, WA USA
[4] Univ Utah, Huntsman Canc Inst, Sch Med, Dept Pediat,Canc Control & Populat Sci, Salt Lake City, UT USA