Immunoprevention of large bowel cancer: an animal model

Bowel carcinomas developing in rats exposed to 1,2-dimethyl-hydrazine (DMH) or N-methyl-N-Nitroguanidine (MNNG) have been used as models for human large bowel carcinomas. These rat tumors express unique antigens and shared embryonic antigens detectable by in vitro techniques and by isograft rejection tests. Although the shared antigens induced a much weaker isograft resistance, it is possible to prevent and/or delay development of primary bowel cancers by immuniation against antigens shared among bowel carcinomas and present also on embryonic cells. Evidence is discussed indicating that it is possible to limit the tumor spread and the appearance of additional primary carcinomas by multimodal immunological manipulation and in a small frequency even to achieve tumor regression.