[1] Univ Bern, Childhood Canc Res Grp, Inst Social & Prevent Med, Bern, Switzerland
[2] Univ Bern, Grad Sch Cellular & Bio Med Sci, Bern, Switzerland
[3] Univ Bern, Grad Sch Hlth Sci, Bern, Switzerland
[4] Cantonal Hosp Graubuenden, Dept Paediat, Chur, Switzerland
[5] Univ Basel, Univ Childrens Hosp Basel, Div Pediat Oncol Hematol, Basel, Switzerland
[6] Univ Bern, Bern Univ Hosp, Inselspital, Pediat Oncol, Bern, Switzerland