EXPRESSION OF P53 AND FLOW CYTOMETRIC DNA ANALYSIS OF ISOLATED NEOPLASTIC GLANDS OF THE STOMACH - AN APPLICATION OF THE GLAND ISOLATION METHOD

The expression of p53 was studied immunohistochemically in combination with the DNA ploidy pattern by gland isolation in 97 alcohol-fixed ga stric lesions. A polyclonal antibody, CM-I, was applied to the paraffi n-embedded sections in this study. Overexpression of the p53 protein w as found in 73.2% of 41 well or moderately differentiated gastric carc inomas and 52.2% of 23 cases with poor differentiation (P<0.05). Immun oreactivity of p53 was also detected in isolated cancerous glands. No p53 immunoreactivity was detected in benign gastric lesions including adenomas, hyperplastic polyps and regions of intestinal metaplasia. In addition, flow cytometric DNA analysis was performed on isolated glan dular epithelium adjacent to the portions used for immunostaining. DNA aneuploidy (DA) was detected in 85.7% of the well or moderately diffe rentiated carcinomas and 42.9% of those with poor differentiation(P<0. 05), There was a positive con-elation between DA p53 positivity and th e presence of regional lymph node metastasis, but not with other clini copathological variables. In spite of the limited applicability of thi s method to poorly differentiated gastric cancer, we found that immuno staining and flow cytometry in combination with the gland isolation me thod facilitates analysis of gastric carcinogenesis.