Incidence of estrogen, progesterone and prolactin receptors in human breast cancer.

Analysis of estrogen and progesterone cytosolic receptors (ER, PR) has been studied in human breast carcinoma. ER were assayed by sucrose density gradients and dextran coated-charcoal method. In a series of 109 ER+ breast tumors, 64.2% exhibited the 8S form, 25% the 4S and 11% both the 8S and 4S components. From a total number of 970 specimens, 776 (80%) were primary and 194 (20%) metastatic lesions. In the whole group, ER was positive in 77.6% and PR in 61.4%, while both receptors were found simultaneously in 59%. The concentration of ER was higher in postmenopausal women in comparison to premenopausal women. On the other hand, the levels of PR were rather similar in both groups. In primary lesions, PR was more frequently seen than in secondary tumors and the same holds true for the presence of ER and PR and the frequency of negative tumors. Specific prolactin (PRL) binding assay was performed in a group of 50 breast tumors. Positive and negative distribution was almost equal (48 vs 52%) and there was not correlation between PRL-R and ER. In addition, a limited group of male breast cancer, showed that three out of five patients possess only androgen receptors, whereas the remaining two cases were exclusively ER+. In summary, the present results indicate that the local incidence of steroid receptors in female breast carcinoma, are very likely similar to previous reports either in premenopausal and postmenopausal women and in primary and secondary lesions. The importance of PRL-R assay requires a further evaluation.