[1] Univ Southampton, LRF Cytogenet Grp, Canc Sci Div, Southampton, Hants, England
[2] Univ Oxford, Clin Trial Serv Unit, Oxford, England
[3] Royal London Hosp, Dept Paediat Oncol, London E1 1BB, England
[4] St James Univ Hosp, Dept Paediat Oncol, Leeds LS9 7TF, W Yorkshire, England
[5] Cent Manchester & Manchester Childrens Univ Hosp, Dept Paediat Oncol, Manchester, Lancs, England
[6] Sheffield Childrens Hosp, Dept Haematol, Sheffield, S Yorkshire, England
[7] John Radcliffe Hosp, Dept Paediat Oncol, Oxford OX3 9DU, England