Serum oestradiol in women with and without breast disease.

It has been suggested that the percentage of non-protein-bound or free oestradiol (E2) is abnormally high in patients with breast cancer. In this study, the serum oestradiol profiles of a large group of women were analysed to determine whether a significant correlation could be found between serum oestradiol and various breast diseases. In addition oestradiol levels were measured in relation to sex hormone binding globulin (SHBG), albumin levels, oestrogen receptor status and family history of breast cancer. Serum samples were taken from a total of 300 women who had either no breast disease, benign breast disease or breast cancer. The percentage of free oestradiol was found to be highest in women with breast cancer, lowest in the control group and intermediate for the women with benign breast disease. These differences were most marked in post-menopausal women. The absolute values for total and free oestradiol were not statistically different in the three groups studied. There did not appear to be a correlation between oestrogen receptor (ER) concentration in breast cancer tissue and free E2 percentage levels. Women who had a family history of breast cancer did not appear to have higher percentage levels of free E2 than those with no such history. The presence of elevated proportions of free oestradiol in the serum of women with breast cancer may be significant in regard to understanding the aetiology of breast neoplasia. There also may be important implications for the use of this measurement in the earlier diagnosis and detection of breast cancer.