摘要：

Samples from 77 primary and 65 metastatic human breast cancers were assayed for specific cytoplasmic estrogen receptors. Cytosol preparations were incubated with increasing amounts of 3H-estradiol-17β. The unbound radioactivity was removed by charcoal-coated dextran. Saturable high affinity binding sites were detected in 56% of the primary and 37% of the metastatic tumors. The binding constants of these receptor sites for estradiol were quite variable; most ranged from 1·0 to 20 × 10−10M, but some were larger (up to 108 × 10−10M). The concentrations of binding sites were distributed within a continuous range from 5 to 1330 femtomoles per mg protein. This wide range was not ascribable only to variations in amounts of contaminating serum proteins. Receptors were detected in only 8% of cytosol preparations containing less than 2 mg protein per ml; in contrast they were detected in 53% of cases with higher protein concentration. This indicates that at low protein concentration, false negative results are likely to occur. Detectable amounts of receptors were not found in sera or samples from normal mammary gland, nipple, areola, skin and non-invaded lymph nodes. The reliability of a simplified procedure based on isotopic dilution of the labelled estradiol, to be used with very small tumor tissue samples, was studied. It compared quite well with the other one except in case of very low concentrations of receptor. No relationship was found between the occurrence of receptor and the age of the patient or the histological type of the tumor. There was also no relationship between the occurrence of receptors in the primary tumor and presence or absence of metastatic axillary lymph nodes. However, when present, the latter had the same characteristics with respect to the receptor as the corresponding primary, with only one exception. In cases of metastatic tumors, no correlation was observed with the free interval.

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