Karyometry of secretory cell nuclei in high-grade PIN lesions

BACKGROUND. The goal of this study was a karyometric characterization of se cretory cell nuclei in high-grade prostatic intraepithelial neoplasia (PIN) lesions. Specifically, the hypothesis is tested that distinctly different subgroups of nuclei exist in these lesions. METHODS. High-resolution images of 1,713 nuclei from high-grade PIN lesions were recorded. Karyometric features were computed. Discriminant function s cores against normal reference nuclei, and nuclear abnormality values were derived. Data sets were processed by a nonsupervised learning algorithm to establish the presence of subgroups of nuclei with statistically different nuclear chromatin distributions. RESULTS. Three sets of nuclei were formed, facing an intact basal cell laye r, a near vanishing basal cell layer, and a gap in the basal cell layer. Fo r each set, a nonsupervised learning algorithm formed three statistically d ifferent subgroups of approximately equal sizes. Each subgroup is found in every one of the three sampling locations. The total optical density distri bution of nuclei in two subgroups suggests an aneuploid distribution, the t hird subgroup has a near diploid distribution. CONCLUSION. Secretory cell nuclei in high-grade PIN lesions are a heterogen eous population, forming statistically different subgroups. Studies aimed a t characterizing the progression of such lesions should consider the inhomo geneous nature of these nuclei.