Figure 1. Representative colonoscopic images from animal models of experimental colon carcinogenesis.

For these longitudinal studies, rat colonoscopy was performed to evaluate tumorigenesis status of animals at the time point of fecal sampling of AOM-treated rat without and with tumor.

A) Twenty-four week old Fisher 344 controls (saline treated) without tumors.

B) Twenty-four week old Azoxymethane (AOM) treated Fisher 344 rats with adenomas.

C) APC Wildtype rat colon (14 weeks old)—no tumor noted.

D) Pirc rat -14 weeks old with evidence of polyposis with numerous adenomas detectable.