Comparison of total cathepsin D in breast tissue of patients with benign and malignant breast disease

Cathepsin D was estimated by immunoradiometric assay in cytosols of breast biopsies from 16 patients with fibrocystic breast disease, 14 patients with fibroadenoma of the breast, 30 patients with ductal carcinoma in situ and seven normal breast tissues from reduction mammoplasties. The results of the groups were compared with one another and with that of a large sample (738) of invasive breast carcinomas from a previous study. The mean cathepsin D concentration in the cytosol was lowest in normal breast tissues, intermediate in ductal carcinomas in situ and adenomas, and highest in invasive carcinomas. Cathepsin D in ‘fibrocystic disease’ covered a wide range; the average was still below the cut off value of 25 pmol/mg protein, but closer to the mean of the invasive carcinomas than that of any other group.