Xenotransplantation (xenografting) of primary cancers or cancer cell lines into immunodeficient mice is a commonly used technique to assess tumor growth in response to a variety of experimental agents. When primary pancreatic cancers are xenografted, cancer cells proliferate in the mouse, but the human stroma does not. This growth pattern enables facile genetic analysis of cancer genetics profiles without the contamination of admixed stromal cells typical of primary cancers.