1. GI & Liver Stem Cell Research Group (GILSteR), Department of Internal Medicine and Gastroenterology, Gemelli Hospital, Largo A. Gemelli 8, 00168 Rome, Italy
2. Institute of Anatomy and Cell Biology, Catholic Univeristy of the Sacred Heart, Largo F. Vito 1, 00168 Rome, Italy
3. Medical Research Foundation ONLUS, Galleria falcone Borsellino 2, Bologna, Italy
4. Department of Surgical Sciences, Gemelli Hospital, Largo A. Gemelli 8, 00168 Rome, Italy