[1] Cardiff Univ, Sect Clin Oncol & Palliat Med, Cardiff, S Glam, Wales
[2] Cardiff Univ, Inst Med Genet, Cardiff, S Glam, Wales
[3] Univ Leeds, St James Inst Oncol, Leeds, W Yorkshire, England
[4] Queens Univ Belfast, Belfast, Antrim, North Ireland
[5] MRC, Clin Trials Unit, London, England