Different autochthonous models of colorectal cancer in the rat.

Chemically induced (autochthonous) tumors in the rodent are thought to be the best models at hand to obtain results transferable to the clinical situation. Four different autochthonous tumor models: 1,2-dimethylhydrazine, N-methylnitrosourea (MNU), N-methyl-N-nitro-nitrosoguanidine (MNNG), and N-nitroso-acetoxymethyl-methylamine (AMMN) which are used worldwide for etiological and therapy studies of colon cancer are compared for tumor biology and clinical relevance. The four tumor models of colon carcinoma described in the rat are different in growth, invasion, and metastases. The choice of the selected tumor model for experimental investigations of colon cancer should depend on the clinical question.