PDX1 and pancreatic neoplasm: Prior to generation of the E-cadherin-GFP mouse, we first established primary non-invasive pancreatic tumor cell lines from Pdx1-Cre; KrasG12D/+; p53flox/+ mice (Morton et al., 2010b) in which the wild-type p53 allele is lost (hereafter referred to as p53−/−).