[Hormonal receptors of malignant breast tumors]

Tissue samples from 166 primary and 136 metastatic breast cancers were analysed for the presence of estrogen receptors. It was found by measuring the affinity of the cytoplasmic fraction of these samples for 3H-estradiol-17 beta that receptors were present in 72 p. 100 and 54 p. 100 of primary and metastatic cancers respectively. Receptor concentration varied among sample in an apparently continuous distribution from zero to 2,080 femtomoles per mg tissue protein. This suggests that mammary tumors are different from one another more in a quantitative than in a qualitative way. Detectable amounts of receptors were found in samples from mammary dysplasia, fibroadenomas as well as from one papilloma; none was detected in samples from non-tumorous mammary gland, nipple areola or skin. At mastectomy, no correlation was found between presence or absence of receptors in the primary tumors, and presence or absence of metastatic axillary nodes. On the other hand both the primary and its axillary metastases almost always displayed the same characteristic as far as presence or absence of receptors was concerned. Analysis of clinical studies reported seems to indicate that women with advanced breast cancer respond in a fair proportion of cases to various endocrine treatments when tumor tissue biopsies contain estrogen receptors whereas the probability of a response is very low in their absence.