Mouse Models of Intestinal Cancer.

Intestinal cancers are a category of heterogeneous tumors that occur sporadically or through inherited susceptibility, each characterized by genetic alterations affecting a number of molecular pathways. As a result of this complexity, numerous genetically engineered mice (GEM) have been generated to model different genetic, morphologic, or clinical features of intestinal cancer. Mouse models of intestinal cancer can be broadly divided into six groups based on the underlying signaling pathway disrupted or by the means with which tumors were induced: Wnt-related GEM; GEM associated with alterations in TGF-beta (β) signaling; mismatch repair-deficient GEM; immunedeficient mice; carcinogen-treated mice; and others that do not neatly fit into the aforementioned categories. Although differences have been noted in lesions arising in these broadly grouped genetic and other models, some characteristics are shared. Adenomas are the most common lesion in mouse models of intestinal cancer. Unlike humans, lesions can be present throughout the intestinal tract, with no predilection for the colon. Invasion and metastasis occur rarely. This chapter will summarize the findings from most of the available mouse models of intestinal cancer.