THE VALUE OF PCNA AND AGNOR STAINING IN ENDOSCOPIC BIOPSIES OF GASTRIC-MUCOSA

The aim of the present study was to examine the usefulness of the quan tification of PC10-positive-cells and of Argyrophilic Nucleolar Organi zer Regions (AgNORs) in gastric biopsies for the identification of gas tric mucosal proliferative lesions. Fifty seven paraffin-embedded endo scopic biopsies were classified into four histologic groups: normal, i nflammatory, dysplastic and neoplastic mucosa. The percentage of PC10- positive cells was determined by immunohistochemistry. The AgNOR param eters determined included the total number of all identifiable silver precipitations in the nucleus, the mean number of silver precipitation s per cluster, and the presence of morphologically heterogenous silver precipitations. Group comparisons were performed using the Kruskall W allis and Dunn non-parametric tests with a significance level of 5%. A dicriminant analysis (followed by the jack-knife procedure) was perfo rmed using the three AgNOR parameters plus the percentage of PCNA-posi tive cells as the independent variables and histological groups as the dependent variable. All three AgNOR parameters, as well as the percen tage of PCNA-stained nuclei, showed their highest values in the carcin oma group. However, no good differentiation among the four histologic groups was obtained using only one of these parameters, since there wa s always considerable overlap among them. By combining all the paramet ers in a linear discriminant analysis, we obtained a correct classific ation in 48 out of 57 cases. Within the classification errors there wa s only one false positive carcinoma, which was in fact a dysplasia and only one false negative carcinoma erroneously classified as dysplasia . The number of cells with heterogenous AgNORs was the most important parameter for the discriminant analysis. No correlation between PCNA v alues and the AgNOR parameters could be found, thus indicating that th ey do not represent the same phenomenon in the cell cycle. We conclude d that the use of a combination of various proliferation parameters in a linear discriminant analysis may be helpful for differentiating gas tric mucosal lesions. The peculiar AgNOR morphology is an important va riable which should be taken in consideration in quantitative studies. PCNA and AgNORs seem to represent different physiological phenomena i n the cell cycle.