MULTIPLE STEROID-RECEPTORS IN HUMAN-BREAST CANCER .2. ESTROGEN AND PROGESTIN RECEPTORS IN 672 PRIMARY TUMORS

Estrogen (E) and progestin (P) receptors (R) were investigated in 672 human primary breast tumors (664 from women and 8 from men). Premenopausal patients have both a lower frequency of ER positive tumors (64%) and a lower ER content (80±63 fmol/mg protein) than postmenopausal women (74% and 249±351 fmol/mg protein). All eight cases of male breast cancer were ER-positive. PR was found in 45% of the tumors. In contrast to ER, the presence of PR and the absolute PR level are not related to patient age. Except for the month of March, the mean monthly ER values do not fluctuate in postmenopausal patients: A peak is observed in the ER content of breast cancer from patients who underwent surgery during the month of March. Absolute ER content appears to be statistically unrelated to the tumorous cellular density (TCD); expression of the results as femtomoles per milligram of protein gives an underestimate of the actual receptor concentration. TCD must thus be considered in interpretation of the ER content. The results are in agreement with the idea that the steroid receptors are a characteristic of a population of cancer cells within a breast tumor and that ovarian factors are implicated in the steroid receptor content. © 1979 Springer-Verlag.