PROSTATIC INTRAEPITHELIAL NEOPLASIA - EXPRESSION AND LOCATION OF PROLIFERATING CELL NUCLEAR ANTIGEN IN EPITHELIAL, ENDOTHELIAL AND STROMAL NUCLEI

The expression and location of proliferating cell nuclear antigen (PCN A) immunostaining in epithelial, endothelial and stromal nuclei were a ssessed in prostatic intra-epithelial neoplasia (PIN). It was then com pared with patterns in benign lesions and in invasive adenocarcinomas of the prostate. The PCNA-positive nuclei showed homogeneous or granul ar types of staining, or a mixture of both, and a gradation in the int ensity of staining. Nuclei with granular and mixed patterns appeared l ighter brown than those with a homogeneous pattern, which were darker and more often noted in PIN and invasive adenocarcinomas than in benig n lesions. For epithelial PCNA-stained nuclei, the proportions in the two grades of PIN were greater than in benign prostatic hyperplasia (m ean 3.16%, SE 0.31%) and prostatic atrophic ducts and acini (mean 0.56 %, SE 0.09%), the values decreasing from the nuclei in the basal posit ion towards those in the luminal layer. In grade 1, the category mean values were 9.51% (SE 1.14%) in the basal, 7.02% (SE 1.27%) in the int ermediate and 6.02% (SE 0.90%) in the luminal position. In grade 2, th e category mean values were 13.81% (SE 1.42%) in the basal position, 1 0.99% (SE 1.17%) in the intermediate and 7.91% (SE 1.43%) in the lumin al position. In small and large acinar adenocarcinomas, the proportion s of positive nuclei were 8.66% (SE 0.30%) and 9.06% (SE 0.30%), respe ctively. The category mean values in the cribriform adenocarcinomas we re 14.40% (SE 0.61%) in the basal position, 11.84% (SE 1.30%) in the i ntermediate and 9.26% (SE 0.66%) in the luminal position. As in PIN, t he proportions of immunostained nuclei in the adenocarcinoma with crib riform pattern decreased from the basal towards the luminal layer. In the solid/trabecular adenocarcinomas, the category mean value in the c ell layer adjacent to the stroma was 17.60% (SE 2.92%), whereas in the other cell layers it was lower than that in the cells adjacent the st roma (mean 13.88%, SE 1.71%). For capillary endothelial and stromal ce lls, the percentages of PCNA-stained nuclei were much lower than those in the epithelial component. The lowest mean values were obtained in benign lesions. whereas the highest were in invasive adenocarcinomas, the percentages in PIN being intermediate.