[1] Sheffield Teaching Hosp NHS Fdn Trust, Dept Upper Gastrointestinal Surg, Sheffield, S Yorkshire, England
[2] Sheffield Teaching Hosp NHS Fdn Trust, Dept Histopathol, Sheffield, S Yorkshire, England
[3] Univ Sheffield, Acad Unit Surg, Northern Gen Hosp, Herries Rd, Sheffield S5 7AU, S Yorkshire, England