PDX1 and pancreatic neoplasm: pancreatic tumors from the widely used murine “KPCY” model, driven by oncogenic KrasG12D mutation and inactivation of both alleles of Trp53 plus a YFP tracer (KPCY mice: Pdx1-Cre; LSL-KrasG12D; Trp53flox/flox; Rosa26-LSL-YFP); 2.