Long-term follow-up study of patients with gastric adenomas with malignant transformation.  An immunohistochemical and histochemical analysis. 
Little is known about the changes in the immunohistochemical and histochemical characteristics that take place during the malignant transformation of gastric adenoma (GA).  Nine patients with GA who developed carcinoma (Group A) and 33 who did not (Group B) during an equivalent follow-up period (mean, 76.4 months; range, 38-166 months) were studied.  Tissue sections from these patients were stained for p53, c-erbB-2, bcl-2, carbohydrate antigen 19-9 (CA 19-9), carcinoembryonic antigen (CEA), and proliferating cell nuclear antigen (PCNA), and by high iron diamine-alcian blue staining.  The gastric or intestinal phenotypes of the GA cells were evaluated histochemically by paradoxical concanavalin A and galactose oxidase-Schiff reactions.  In Group A, the following were more frequent; severe dysplasia (77.8% vs. 0%, P < 0.001), villous structures (66.7% vs. 9.1%, P < 0.05), sulfomucin secretion (88.9% vs. 39.4%, P < 0.05) and mixed gastric-intestinal phenotype (77.8% vs. 9.1%, P < 0.001).  The development of carcinoma in Group A positively correlated with an increase in p53 expression and PCNA-labeling index.  None of the adenomas was positive for c-erbB-2, but four of nine carcinomas showed positive reactions.  Mucin histochemistry of GA may be of some value in assessing the potential for subsequent carcinoma.  Immunoexpression of c-erbB-2, bcl-2, CA 19-9, and CEA have only limited value.  In contrast to p53, the immunoexpression of c-erbB-2 is a late event in the malignant transformation of GA.