ANALYSIS OF THE CAPILLARY ARCHITECTURE IN THE PRECURSORS OF PROSTATE-CANCER - RECENT FINDINGS AND NEW CONCEPTS

Objective: To report on recent findings and new concepts in the remode ling of the capillary architecture in the precursors of prostate cance r. Methods: Immunohistochemical methods have been adopted in prostate cancer and in its precursors (prostatic intra-epithelial neoplasia) to investigate capillary pattern changes - which were mainly analyzed as capillary frequency - and the degree of endothelial cell proliferatio n. Several features related to the capillary architecture have been co nsidered. Manual, semiautomatic, and automatic (machine vision) types of evaluation have been used to quantify the features. Results: The da ta available indicate that: (1) Going from normal prostate through pro static intra-epithelial neoplasia up to invasive adenocarcinoma, an in creasing proportion of capillaries becomes shorter, with open lumen an d undulated external contour and with greater proliferation of the end othelial cells and greater expression of type IV collagenase. The high est proportion of touching capillaries is seen in normal prostate, whi le the lowest is found in invasive adenocarcinoma, being intermediate in prostatic intra-epithelial neoplasia. (2) When total androgen ablat ion is induced, there is no proliferation of the endothelium, whereas the capillaries are reduced in frequency and represented by small vess els lined by flat endothelial cells and with an open lumen. (3) Automa tion in the evaluation of the capillary architecture is feasible with a machine vision system. Conclusions: The progression in prostate carc inogenesis is associated with changes in the capillary architecture. T here are some preliminary data indicating that total androgen ablation can inhibit the angiogenesis in precursors of prostate cancer.