1 Division of Experimental Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK; Division of Internal Medicine, Universitá degli Studi del Piemonte Orientale, Department of Clinical and Experimental Medicine, Novara, Italy.
2 Department of Oncology, Imperial College London, Hammersmith Campus, Du Cane Road, London, UK.
3 Department of Gastroenterological Surgery, Dokkyo Medical University, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan.
4 Department of Hepatology and Gastroenterology, Imperial College London, St. Mary's Campus, Praed Street, London, UK.
5 Statistical Advisory Service, Imperial College London, London, UK.
6 Division of Experimental Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK. Electronic address: r.sharma@imperial.ac.uk.