PDX1 and neoplasm: Genetically engineered mouse models (GEMMs) use mice bearing oncogenes that initiate a primary tumour (quite often, multiple primary tumours), which in some cases progress to metastatic disease (for example, the LSL-KrasG12D/+; LSL-Tp53R172H/+; Pdx1-Cre KPC GEMM used for preclinical studies of both pancreatic cancer prevention and therapy66).