SPECIFIC ESTROGEN BINDING BY THE CYTOPLASM OF HUMAN BREAST CARCINOMA

Abstract

ABSTRACT Increased recognition of the importance of selective hormone binding in initiation of steroid action in target tissues led us to study estrogen binding by human breast cancer. Mastectomy specimens were obtained from 4 premenopausal and 11 post-menopausal women ranging in age from 37 to 83 yr. They were characterized histologically as infiltrating ductal carcinoma in 9, adenocarcinoma in 5, and colloid carcinoma in one. The capacity of the high-speed ultracentrifugal supernatant (cytosol) of homogenates of mammary carcinoma, glandular tissue and fat, was tested for the ability to bind tritiated 17β-estradiol (E2-3H) by the radioligand binding technique we previously described for uterus. Glandular tissue and fat from all 15 mastectomy specimens failed to bind E2-3H, as did 7 tumors. One tumor had slight steroid binding activity which was unsaturable and nonspecific. Seven tumor cytosols had E2 binding capacities in excess of 0.8, 0.8, 5.1, 10.0, 10.5, 19.5 and 21.3 × 10−14 moles/mg protein. Testos...