Oestrogen-receptor status and endocrine therapy of breast cancer: response rates and status stability

Abstract

The concentration of cellular oestrogen receptor (RE) was measured in both the soluble and nuclear-pellet fractions of biopsies from 1,000 breast cancers. Data suggest that functional steroid RE is always in equilibrium between the soluble and nuclear fractions. However, biopsies from only one-third of patients contained detectable amounts of high-affinity RE in both fractions. Thirty patients out of 42 (71%) whose biopsies contained RE in both fractions, showed objective remission after receiving some form of hormonal manipulation as sole treatment. Response rates in the other categories ranged from 9% for those whose biopsies contained no detectable RE to 24% for those who displayed soluble RE alone. The presence of RE in both fractions of primary disease, whereas RE-negativity was maintained during progression from primary to secondary disease. Other aspects of RE status in relation to stage of disease are analysed.

PIP: Both the soluble and pellet RE (estrogen receptor) status of 1000 patients with breast cancers were measured. Functional steroid RE was found to be always in equilibrium between the soluble and nuclear fractions. Detectable amounts of high affinity RE in both fractions were seen in biopsies from only 1/3 of patients. 30 out of 42 patients (71%) whose biopsies contained RE in both fractions exhibited objective remission following hormonal manipulation as sole treatment. Response rates in other categories ranged from 9% for those whose biopsies had no detectable RE to 24% for those who exhibited soluble RE alone. RE presence in both fractions of primary disease was found to be an unreliable index of RE status in subsequent secondary disease while RE negativity was maintained during progression from primary to secondary disease. Other aspects of RE status in relation to stage of disease are analyzed.