Plasma membrane enzymes in human breast carcinoma: relationship with serum hormones.

Alkaline phosphatase, 5'nucleotidase and gammaglutamyl transferase were studied in premenopausal and post-menopausal women with fibroadenoma and breast carcinoma tissues. The relationship of circulating estradiol (E2) and prolactin (Prl) with these enzymes was also investigated. All the three enzyme activities were found to be elevated in the breast carcinoma tissues of both pre- and postmenopausal groups. None of the membrane bound enzymes studied was altered in fibroadenoma breast tissues. The activities of all the three enzymes in breast carcinoma tissues were stimulated by the elevated level of serum Prl and further stimulated by a simultaneous increase in E2.