Cellular localization of estrogen binding sites in human breast cancer.

Biopsy specimens from 52 consecutive cases of primary human breast cancer were collected over a period of seven months and included in a study for histochemical localization of estrogen binding sites (EBS), using a fluorescein labelled Estradiol conjugate. Cryostat frozen sections from each tumor were examined to determine the localization of the tracer and to evaluate the percentage of positive cells in a given tumor. Results are correlated with the values of the biochemical assay for the estrogen receptor (ER) protein done on the same tumor. The localization of EBS by a tracer is a simple technique that can be done and interpreted in any surgical pathology laboratory. It was concluded that this method could be a valuable supplementary technique to the biochemical assay; allowing more accurate selection of patients and prediction of their response to endocrine therapy. Clinical follow-ups are extremely necessary to evaluate the suitability and the accuracy of the technique in choosing breast cancer patients for endocrine manipulation.