INFLUENCE OF TAMOXIFEN ON THE TUMOR CONTENT OF STEROID-HORMONE RECEPTORS (ER, PGR AND AR) IN PATIENTS WITH PRIMARY BREAST-CANCER

A possible influence of tamoxifen (TAM) treatment on the measurable co ntent of some Steroid hormone receptors (i.e. ER, PgR, AR) from primar y breast cancers has been evaluated. In eleven postmenopausal women, t wo biopsies were taken from the same tumor, the first biopsy before st arting endocrine treatment, and a second biopsy after 8 weeks on tamox ifen treatment. A significant decrease in ER content was found both us ing a ligand binding (p < 0.005) and an enzyme immunoassay (p < 0.02). As for the PgR and AR content, no significant changes in the mean con tent were found.