Carcinoembryonic Antigen (CEA) in N-methyl-N'-nitro-N-nitrosoguanidine-Induced Gastrointestinal Carcinomas of the Rats

Abstract

Immunohistologic findings on carcinoembryonic antigen (CEA) and its serum level were compared in N-methyl-N' -nitro-N-nitrosoguanidine (MNNG)-induced gastrointestinal malignant tumors. Of fifty-six malignant neoplastic lesions developed from 39 rats, only 10 carcinomas were CEA positive (10.7% of gastric and 31.8% of small intestinal cancers) in cytoplasm of tumor cells by peroxidase-antiperoxidase (PAP) staining method. Animals with CEA positive carcinoma showed the highest level of serum CEA than any other groups, but the difference was not statistically significant (0.964 ± 0.150 versus 0.883 ±0.094). The above findings lead to the suggestion that experimental gastric carcinoma expresses lower CEA positivity than intestinal carcinoma, comparatively similar to the reported results in human cases.