Decrease of circulating level of SHBG in postmenopausal obese women as a risk factor in breast cancer: reversible effect of weight loss.

Levels of circulating estrone (E1), estradiol (E2), androst-4-ene-3,17-dione (Adione), 3,5,3'-triiodothyronine (T3), thyroxine (T4), and sex hormone-binding globulin (SHBG) were measured in 10 obese postmenopausal patients with breast cancer and in 10 obese postmenopausal control subjects matched for age, body size, and menopausal status. T3, T4, and SHBG were also measured in 10 lean postmenopausal control subjects. In cancer patients after mastectomy, the cytosolic estrogen receptors (E2R) in tumor specimens were determined.

Peripheral aromatization as a risk factor for breast and endometrial cancer in postmenopausal women: a review.

In menopause, estrogens are produced almost exclusively through peripheral aromatization of androgens, especially androstenedione. Obesity increases the production rate of estrogens by means of the same mechanism. In postmenopause, plasma levels of SHBG diminish significantly.