Correlation of estrogen and progesterone receptors and histological grade in human primary breast cancer.

The relationships between the presence of female sex steroid receptors and their concentrations, and the histological grade were investigated in primary breast carcinoma specimens from 151 patients. The concentrations of estrogen receptor were significantly lower in grade III tumours than in the more differentiated ones from pre- and post-menopausal patients, whereas the same was observed for progesterone receptor concentrations only between grades III and I in post-menopausal patients. Generally estrogen and progesterone receptor-positive, estrogen receptor rich tumours frequently belonged to well-differentiated tumour categories. Whereas most of the tumours belonging to grade III group were receptor-negative, approximately three fourths of receptor-negative tumours belonged to grade I and II categories. It is therefore suggested that estrogen receptor-negativity or low receptor concentrations and grade III histological appearance of breast carcinoma are independent risk indicators, and their concomitant use is recommended in designing treatment strategies for individual patients.