[1] Inst Canc Res, Div Clin Studies, Sutton, Surrey, England
[2] Inst Canc Res, Div Radiotherapy & Imaging, Sutton, Surrey, England
[3] Inst Canc Res, Div Mol Pathol, Sutton, Surrey, England
[4] Indiana Univ, Dept Neurol Surg, Bloomington, IN USA
[5] Hosp Sick Children, Dept Pediat, Toronto, ON, Canada
[6] Univ Leeds, Fac Biol Sci, Leeds, W Yorkshire, England