Colin J Rees1,2, Sara Koo3. 1. Northern Institute for Cancer Research, Newcastle University, Newcastle, UK. colin.rees@newcastle.ac.uk. 2. Department of Gastroenterology, South Tyneside NHS Foundation Trust, South Shields, UK. colin.rees@newcastle.ac.uk. 3. Department of Gastroenterology, South Tyneside NHS Foundation Trust, South Shields, UK.