Intestinal microflora are necessary for development of spontaneous adenocarcinoma of the large intestine in T-cell receptor beta chain and P53 double-knockout mice

This study was conducted to confirm the hypothesis that intestinal microflo ra are required for the development of adenocarcinoma in the colon of the T CR beta and p53 double-knockout (TCR beta (-/-) p53(-/-)) mouse. Germ-free TCR beta (-/-) p53(-/-) mice were produced. At 7 weeks of age, the animals were divided into two groups (n = 10/group), and one of these groups was co nventionalized. Animals of both groups were subjected to histopathological examination for adenocarcinoma of the colon at 4 months of age. There was n o development of adenocarcinoma of the colon among the germ-free mice, wher eas in the conventionalized group, adenocarcinomas of the ileocecum and cec um were detected in 70% of animals. These results indicate the usefulness o f the TCR beta (-/-) p53(-/-) mouse as a colon cancer animal model that dev elops spontaneous adenocarcinoma of the colon early in life, and suggest th at intestinal microflora play a major role in the development of adenocarci noma of the colon in this animal model.