Alpha 1-antitrypsin as a biomarker in azoxymethane induced intestinal tumors in F344 rats.

Alpha 1-antitrypsin (alpha 1AT) has been detected in several human tumors and is thought to be a marker of neoplastic change and progression. As the biology of azoxymethane (AOM) induced intestinal tumors in F344 rats has many characteristics of human intestinal tumors, we have investigated alpha 1AT expression in AOM induced rat intestinal tumors. Nine of 12 colonic carcinomas and 6/8 small intestinal carcinomas had alpha 1AT positive tumor cells. Only 1/11 colonic adenomas and 0/3 small intestinal adenomas contained alpha 1AT. Thus alpha 1AT is a marker of malignancy in this model. Inhibition of carcinogenesis by piroxicam and difluoromethyl ornithine inhibited alpha 1AT expression.