[1] Univ Washington, Fred Hutchinson Canc Res Ctr, Sch Med, Div Clin Res, Seattle, WA 98195 USA
[2] Univ Washington, Sch Med, Div Hematol, Med, Seattle, WA 98195 USA
[3] Univ Washington, Sch Med, Dept Lab Med & Pathol, Seattle, WA 98195 USA
[4] Univ Washington, Sch Publ Hlth, Dept Epidemiol, Seattle, WA 98195 USA