Relation between steroid receptor content and the response to hormone addition in isolated human breast cancer cells in short-term culture.

The hormone dependence of human breast tumors has been investigated in two ways: (a) estradiol and progesterone receptor determination in tumor tissue; and (b) measurement of the growth-stimulating effect of hormones on cells in short-term culture. Preliminary results from 15 tumors suggest that such a model may be used for human breast tumors. The behavior of the cultures under hormonal stimulation depended on their receptor content. In this series of patients, the tumors containing both estradiol and progesterone receptors were stimulated by addition of insulin and estradiol while the tumors containing either estradiol receptor alone or no steroid receptor were not modified by hormonal addition.