Expression of cathepsins B and S in the progression of prostate carcinoma

Cathepsins B and S (CatB, CatS) are lysosomal cysteine proteases which, among other functions, appear to play a role in cancer progression in different tumor models due to their matrix-degrading properties. To investigate their possible involvement in the development of prostate carcinoma, we immunohistochemically analyzed Cats and CatS in 38 primary human prostatic adenocarcinomas, as well as concomitant high-grade prostatic intra-epithelial neoplasia, nodular hyperplasia and normal tissue. Cats expression was observed in 28 (74%) and CatS in 32 (84%) carcinomas, being concomitant in 24 cases (63%), High-grade intra-epithelial neoplasia expressed Cats in 20/23 cases (87%), and a similar result was obtained for CatS, with expression of both coinciding in 18 cases (78%), In non-neoplastic tissue, strong expression of both proteases was observed in macrophages, inflamed glands and transitional metaplasia, whereas atrophic glands and basal cells of normal glands displayed intense Cats positivity. We conclude that Cats and CatS are often expressed together in neoplastic prostatic cells from preinvasive to invasive and clinically detectable stages, suggesting a putative role in local invasion, though other functions cannot be ruled out. (C) 2001 Wiley-Liss. Inc.