Modeling pancreatic cancer in vivo: from xenograft and carcinogen-induced systems to genetically engineered mice.

In the last 10 years, there has been a relative explosion of new rodent systems that recapitulate both genetic and cellular lesions that lead to the development of pancreatic cancer. These models now need to be considered when selecting an appropriate in vivo system to study disease etiology, cell signaling, and drug development. The majority of these evaluations have used transplantation of cancer cells and the use of carcinogens, which still maintain their value when investigating human cancer and epigenetic contributors. Xenograft models utilize cultured or primary pancreatic cancer cells that are placed under the skin or implanted within the pancreas of immunocompromised mice. Carcinogen-induced systems rely on administration of certain chemicals to generate cellular changes that rapidly lead to pancreatic cancer. Genetically modified mice are more advanced in their design in that relevant genetic mutations can be inserted into mouse genomic DNA in both a conditional and inducible manner. Generation of mice that develop spontaneous pancreatic cancer from a targeted genetic mutation is a valuable research tool, considering the broad spectrum of genes and cell targets that can be used, producing a variety of neoplastic lesions and cancer that can reflect many aspects of human pancreatic ductal adenocarcinoma.