Absence of seasonal variation of estrogen receptor levels in human breast cancer tissue.

ABSTRACT

The concentration of estrogen receptors was measured in 979 human primary breast cancer tumors obtained during 4 consecutive years. Of these tumors, 631 were classified receptor positive and originated from 212 premenopausal and 419 postmenopausal patients. A modified EORTC procedure was used to quantify the receptor content. Several statistical analyses were performed on the data from the premenopausal and postmenopausal patients separately and on the combined data. The results of these analyses do not support the existence of any periodicity in the estrogen receptor level which is significant and consistent from year to year.