[1] St Marys Hosp, Dept Med Genet, Manchester M20 8LR, Lancs, England
[2] Christie Hosp NHS Trust, CRC, Dept Med Oncol, Manchester M20 4BX, Lancs, England
[3] CLRC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England
[4] De Montfort Univ, Fac Sci Appl, Leicester LE1 9BH, Leics, England