In vitro estrogen-binding by human breast carcinomas.

Patients whose breast carcinomas possess only low concentrations of a receptor molecule that binds estrogens with high affinity are unlikely to respond to hormonal manipulative therapy when the disease recurs. The estrogen-binding capacity of 106 breast carcinomas was measured by an in vitro method and was expressed per milligram wet weight and in some cases related to the concentration of deoxyribonucleic acid (DNA) of the tumours. The ability of tumors to bind 3H-estradiol ranged from 0 to 1.3 fm/mg in pre- and perenopausal women, and from 0 to 16.8 fm/mg in postmenopausal women. Menopausal status or serum concentrations of endogenous estrogen, or both, should therefore be considered when tumours are classified into low and high estrogen-binding capacity. It is not necessary to carry out Scatchard analysis for every tumour, and expressing estradiol binding on the basis of DNA concentration may be preferable to expressing in on a wet-weight basis.