IMMUNOHISTOCHEMICAL ANALYSIS OF CATHEPSIN-D IN PROSTATE CARCINOMA

Cathepsin D is a carboxyl protease that has been implicated as an impo rtant factor in tumor cell invasion. Sixty-nine cases of primary adeno carcinoma of the prostate were studied by the indirect immunoperoxidas e method using a primary monoclonal anti-cathepsin D antibody. Immunor eactivity was graded from 0 (negative) to 4+ (intense reaction). The n ormal tubuloalveolar glands were, in general, negative. However, nine cases revealed focal staining of nonneoplastic luminal cells. Basal ce lls were negative except in areas of basal-cell hyperplasia, which wer e intensely positive. Thirty-nine of 78 carcinoma samples revealed 2or greater positive punctate lysosomal staining. In the 39 positive-st ained cases, the reactivity was diffuse in three and focal in the rema inder. The percentage of carcinoma cases whose worst lesions stained 2 + or greater showed a nonsignificant (P = 0.055) relation to Gleason g rade but a significant (P = 0.031) relationship to pathologic stage. T hus, cathepsin D may prove to be a useful marker of prostate cancer pr ogression.