1. Cancer Epidemiology and Health Services Research Group; Centre for Public Health; Queen's University Belfast; Belfast UK
2. Department of Pathology; Belfast Health and Social Care Trust; Belfast UK
3. Centre for Cancer Research and Cell Biology; Queen's University Belfast; Belfast UK
4. Northern Ireland Molecular Pathology Laboratory; Centre for Cancer Research and Cell Biology; Queen's University Belfast; Belfast UK
5. Department of Gastroenterology; Belfast Health and Social Care Trust; Belfast UK