[1] Royal Hallamshire Hosp, Acad Surg Oncol Unit, Dept Surg, Sheffield S10 2JF, S Yorkshire, England
[2] Royal Hallamshire Hosp, Dept Histopathol, Sheffield S10 2JF, S Yorkshire, England
[3] Univ Sheffield, Acad Surg Oncol Unit, Sheffield, S Yorkshire, England