Expression of transforming growth factor alpha in experimental gastric carcinogenesis.

The induction of adenocarcinomas in the glandular stomach of the adult male Wistar rat by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was used as a model to study the expression of the growth promoting peptide, transforming growth factor alpha (TGF alpha), during experimental gastric carcinogenesis. TGF alpha was identified using the monoclonal antibody Ab-2 and standard immunohistochemistry, together with a semiquantitative assessment of the intensity of expression. Immunoreactivity was confined to the differentiated compartment of the mucosa while the carcinogen MNNG caused a significant increase in the intensity of TGF alpha expression (p < 0.01), after as little as 16 weeks' exposure. In experimental adenocarcinomas, a change to a previously undescribed pattern of perinuclear TGF alpha expression was found, which may represent the site of intense TGF alpha production in the Golgi apparatus after malignant transformation.