[1] Royal Victoria Hosp, Dept Pathol, Belfast, Antrim, North Ireland
[2] Mater Infirmorium Hosp, Dept Hepatopancreaticobiliary Surg, Belfast, Antrim, North Ireland
[3] Royal Victoria Infirm, Dept Cellular Pathol, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England
[4] Newcastle Univ, Inst Cellular Med, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England