1. Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee , Dundee , UK
2. Tayside Cancer Centre, Ninewells Hospital and Medical School , NHS Tayside, Dundee , UK
3. Department of Upper Gastrointestinal Surgery, University Hospital Hairmyres , East Kilbride , UK
4. School of Medicine, Dentistry and Nursing, University of Glasgow , Glasgow , UK
5. Department of Upper Gastrointestinal Surgery, Glasgow Royal Infirmary , Glasgow , UK
6. Department of Oncology, Edinburgh Cancer Centre , Edinburgh , UK
7. Department of Oncology, Aberdeen Royal Infirmary , Aberdeen , UK
8. Department of Upper Gastrointestinal Surgery, University Hospital Wishaw , Wishaw , UK