PDX1 and neoplasm: To directly address this question, we co-injected pancreatic fibroblasts, in which Smo was deleted by Cre/loxP technology, with a luciferase-tagged mouse KPC-luc tumor cell line (derived from LSL-KrasG12D/+; TP53loxP/loxP; Pdx1-Cre mice [Hwang et al, 2008]) directly into the pancreas of nude mice (see the Materials and Methods section for description of cell lines used).