THE EFFECT OF TREATMENT WITH 4-HYDROXYANDROSTENEDIONE OR MEDROXYPROGESTERONE ACETATE ON HUMAN BREAST-TUMOR REGRESSION

We have assessed cell deletion in breast tumours removed surgically fr om postmenopausal women by measuring the distribution ratio of acid ph osphatase activity between the bound (in the lysosome) and free (in th e phagosome) states. In benign breast tumours the acid phosphatase dis tribution ratio was much higher than that found in untreated malignant breast tumours. The acid phosphatase distribution ratio was also meas ured before and after treatment in malignant breast tumours removed fr om eight patients treated with 4-hydroxyandrostenedione (4-OH A) and i n six patients treated with medroxyprogesterone acetate (MPA). Elevate d acid phosphatase distribution ratios in benign compared with maligna nt tumours, and in malignant tumours after treatment from four of eigh t patients treated with 4-OH A and from three of six patients treated with MPA, may suggest higher cell deletion in these patients.