[Competitive binding assay with dextran-coated charcoal for measurement of sex hormone-binding globulin in breast cancer].

A simplified method for determination of the binding capacity of the sex hormone binding globulin (SHBG-BC) in human serum and its clinical application are described. This method is based on the estimation of the amount of estradiol (E2) bound with SHBG which possessed binding sites with it. After removing the endogenous steroids from the serum-samples by adsorption with dextran coated charcoal, the value of SHBG-BC increased by 18% compared with that of untreated serum. In 48 patients of various ages with breast cancer, the value of SHBG-BC (34.6 +/- 11.1; mean +/- S.D.), expressed as pico mole per 1 ml serum, did not differ significantly from that of 12 healthy control women (29.6 +/- 6.6). However, in postmenopausal women, the value of SHBG-BC in 24 patients with breast cancer (33.4 +/- 12.2) differed from that of 6 controls (26.1 +/- 4.9; p less than 0.05). In addition, estrogen receptors (ER) were measured by using gel-filtration method in cytosols from the tissue of breast cancer. The value of SHBG-BC in 15 ER-positive cases (40.4 +/- 10.1) was significantly higher than that in 13 ER-negative cases (29.3 +/- 8.7; p less than 0.01), but the value of SHBG-BC and ER did not run parallel completely.