Corticosteroid-binding globulin as a biologic assay for endogenous estrogen in patients with and without endometrial...

Serum corticosteroid-binding globulin (CBG) concentrations in blood respond to endogenous or exogenous estrogens in a dose-response manner and serve as a biologic assay for estrogens. Because endometrial carcinoma is associated with unopposed or excessive estrogen stimulation, the CBG binding capacity of sera of patients with endometrial cancer was compared to that of normal premenopausal and postmenopausal women. The mean +/- SEM values for CBG concentrations in patients with endometrial cancer (28.3 +/- 1.3 mg/L) were significantly greater than CBG concentrations in premenopausal women (21.4 +/- 0.9 mg/L, p less than 0.001), but not significantly different from those of normal postmenopausal women (26.7 +/- 1.2 mg/L). Patients with polycystic ovarian disease, a risk factor for endometrial carcinoma, also had CBG concentrations significantly greater than those of normal premenopausal women (27.9 +/- 1.8 mg/L, p less than 0.01). CBG levels decline with age (r = -0.6474, p less than 0.05) but are unaffected by body weight or percent ideal body weight. These results indicate that CBG can distinguish categories of patients at risk for endometrial carcinoma, but it is not an effective biochemical marker for patients in these high-risk groups who have or will develop endometrial carcinoma.