[1] Univ Dundee, Ninewells Hosp, Ctr Res Canc Prevent & Screening, Dundee DD1 9SY, Scotland
[2] Med Sch, Dundee DD1 9SY, Scotland
[3] NHS Natl Serv Scotland, Informat Serv Div, Glasgow, Lanark, Scotland
[4] Ninewells Hosp, Dept Pathol, Dundee, Scotland
[5] South Tyneside Dist Hosp, Dept Gastroenterol, South Shields, England
[6] Univ Newcastle, Newcastle Upon Tyne, Tyne & Wear, England
[7] Publ Hlth England, Manchester, Lancs, England