Studies on nuclear estradiol receptors in human mammary carcinomas

Nuclear estradiol receptors (NER) were measured in human breast carcinomas by extracting nuclei with 0.6 mol/l KCl and adsorption to hydroxylapatite. NER were found in 34/58 tumors containing cytoplasmic estradiol receptors (CER) and in only 8/34 tumours without CER. NER correlated with CER but not with cytosol total estrogens or progesterone. NER levels also showed no significant correlation with either tumor stage, grade, cellularity, size, or presence or absence of axillary node metastases.