Factors affecting estrogen receptors in breast cancer.

Estrogen receptor contents (ER), determined by a sucrose gradient method in 250 primary or metastatic breast cancers, were analyzed with respect to the influence of the patient's menopausal status, chemotherapy, and tissue sampling. The incidence of the presence of estrogen receptors (ER+) increased in the order of para-, pre- and postmenopausal status of the patient, suggesting that a tumor occurring at the paramenopausal phase tends to be a hormone-independent type. Chemotherapy did not alter the incidence of ER(+), nor the quantity of ER in metastatic lesions. Multiple biopsies done simultaneously or sequentially in the same patient are consistent in their qualities and quantities of ER, provided histological confirmation and examination of the amount of cellularity are included in the process of interpretation.