Hormonal and personal effects on estrogen receptors in breast cancer.

Abstract

Since high estrogen receptor protein in breast cancer tissue has a favorable effect on patient prognosis, factors influencing estrogen receptor levels are the focus of this research. From April 1977 to December 1978, 246 histologically confirmed primary breast cancer patients from three North Carolina hospitals were interviewed and provided with photographic displays of hormonal products. Their tumor tissue was analyzed for estrogen receptor protein by the sucrose density gradient assay. Data were analyzed by multiple regression and logistic regression techniques. No statistically significant relationship was found between gonadal hormone usage and estrogen receptor levels, although recent users of either oral contraceptives or replacement estrogens had lower receptor levels. Users of progestogen-predominant and -intermediate types of oral contraceptives also had lower estrogen receptor protein. An effect of menopausal status, independent of age, was not evident. Statistically significant associations involved age and race among postmenopausal patients. With black breast cancer patients aged less than 70 years as the reference group, the relative odds of having high estrogen receptor protein (greater than 10 fmol/mg of cytosol protein) were 2.4 times greater among whites aged less than 70, 1.6 times greater in blacks aged greater than or equal to 70, and 12.8 times greater in whites greater than or equal to 70 years. These differences in estrogen receptor protein may contribute to the black-white differential in breast cancer survival.