Previous studies have shown that mutant K-ras expression in mice (using K-ras4bG12D, K-rasG12D or K-rasV12 alleles) is sufficient to initiate lung adenomas and adenocarcinomas 7, 9, 10, and pancreatic tumours 33 with few additional genetic or epigenetic alterations. This evidence concerns the gene KRAS and pancreatic neoplasm.