[1] St James Univ Hosp, Dept HPB Surg, Leeds LS9 7TF, W Yorkshire, England
[2] Univ Leeds, Leeds Inst Canc & Pathol, Dept Pathol & Tumour Biol, Leeds LS9 7TF, W Yorkshire, England
[3] St James Univ Hosp, Leeds Inst Canc & Pathol, Canc Epidemiol Grp, Leeds LS9 7TF, W Yorkshire, England
[4] St James Univ Hosp, Leeds Inst Biomed & Clin Sci, Dept Colorectal Surg, Leeds LS9 7TF, W Yorkshire, England