Steroid hormone receptors and human breast cancer

Steroid hormone receptor (SR) binding capacity can be measured both in the cytosol and in the nuclear fraction of the cancerous cells. Approximately 30-40% of breast cancers are hormone dependent. SR-positive tumors can be treated by endocrine therapy resulting in a favourable clinical response in 60-70% of the cases. At the National Institute of Oncology, Budapest, Hungary, estradiol (ER) and progesterone (PR) receptor assays are performed by a multipoint saturation analysis using Scatchard plot. Dextran coated charcoal technique is used for the separation of free and receptor protein-bound labelled hormones. Data obtained from 400 breast cancer patients show a correlation between the SR content of the tumor and the hormonal status of the patients. The ER binding capacity is higher after menopause compared to the premenopausal values. Specific correlation between the PR content of the tumor and the hormonal status of the patients cound not be observed. The PR binding capacity is the highest over 20 years. The highest clinical response rate, 80%, could be found in the group of patients with both ER and PR in their tumor tissues. (author)