1. Cancer Research Program, Garvan Institute of Medical Research, Sydney; Departments of Surgery and Gastroenterology, Bankstown Hospital, University of New South Wales, Bankstown; Department of Anatomical Pathology, Royal North Shore Hospital, University of Sydney, St Leonards; Department of Surgery, Liverpool Hospital, Liverpool; and Department of Anatomical Pathology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.