The use of single transgenic or knockin systems in combination with Cre-lox models that target non-parenchymal cells in the pancreas can circumvent some of the limitations that arise when using Cre-lox to drive an initiating event like mutant Kras. The EL-KRAS model may be a prime candidate for combined Cre-lox targeting of other cell types, as these mice develop acinar-to-ductal metaplasia and cystic papillary neoplasms (CPN) that resemble human cystic disease in the pancreas. This evidence concerns the gene KRAS and papillary cystic neoplasm.