StellaTUM: current consensus and discussion on pancreatic stellate cell research. Issue 2 (24th November 2011) - Erkan, Mert; Adler, Guido; Apte, Minoti V; Bachem, Max G; Buchholz, Malte; Detlefsen, Sönke; Esposito, Irene; Friess, Helmut; Gress, Thomas M; Habisch, Hans-Joerg; Hwang, Rosa F; Jaster, Robert; et al.