CATHEPSIN-D CYTOSOLIC ASSAY AND IMMUNOHISTOCHEMICAL QUANTIFICATION INPROSTATE TUMORS

We quantified cathepsin D by immunoradiometric assay (IRMA) and quanti tative immunohistochemistry in fifteen human prostate cancers, sevente en BPH, and nine normal prostates. The cytosolic cathepsin D concentra tion was higher in prostatic carcinoma (mean: 31.5 pmol/mg cytosol pro teins; range: 10.2-66.2) than in normal prostate (16.0 pmol/mg cytosol proteins; 7.2-25.5; P = 0.01). Prostatic hyperplasia showed intermedi ate values (20.2 pmol/mg cytosol proteins; 7.6-33.9). Immunostaining o f cathepsin D and prostatic acid phosphatase on serial frozen sections of prostate tissues was only observed in glandular epithelial cells. Immunostaining was quantified by computer-assisted image analysis as a n quantitative immuno-cytochemical score (QIC score) expressed in arbi trary units (A.U.). QIC scores for cathepsin D were dispersed and had a tendency to be higher in benign prostatic hyperplasia (mean: 178.3 A .U.; range: 95-297) compared to normal prostate (85.2 A.U.; 2-173 P < 0.01) and prostatic carcinoma (90.0 A.U.; 21-179 P = 0.0002). Prostati c cathepsin D levels in cytosols or immunostaining sections were indep endent of other clinicobiological parameters. (C) 1994 Wiley-Liss, Inc .