Plasma sex hormone-binding globulin (SHBG) and obesity in breast cancer patients.

The important finding was that sex hormone-binding globulin (SHBG) binds 5 alpha-dihydrotestosterone (DHT) with more efficacy than 17 beta-estradiol in patients with breast cancer and that SHBG binds it with less efficacy than 17 beta-estradiol in normal women. An unexpected finding was that there was no correlation between SHBG-binding capacity for 17 beta-estradiol and that for DHT of the same plasma. On the basis of these findings, we confirmed that SHBG-binding capacity for 17 beta-estradiol was a useful predictive index of hormone dependence of human breast cancer. We studied the correlation between SHBG-binding capacity for 17 beta-estradiol and Kaup Index as an index of obesity to examine the interaction between obesity and carcinogenesis of hormone-dependent breast cancer. Significant positive correlation between SHBG-binding capacity for 17 beta-estradiol and Kaup Index was achieved in premenopausal patients. Our results indicate that obesity is an important risk factor for carcinogenesis of hormone-dependent breast cancer.