1 Department of Surgery, University Hospital Limerick, Mid-Western Region, Ireland and School of Medicine, Education Health Sciences, University of Limerick, Limerick, Ireland. Electronic address: calvin.coffey@ul.ie.
2 Guangdong Provincial Key Laboratory of Gastroenterology Institute of Gastroenterology of Guangdong Province Department of Gastroenterology, Nanfang Hospital Southern Medical University, Guangzhou, China. Electronic address: bailan_99@yeah.net.
3 Guangdong Provincial Key Laboratory of Gastroenterology Institute of Gastroenterology of Guangdong Province Department of Gastroenterology, Nanfang Hospital Southern Medical University, Guangzhou, China.