Estrogen and progesterone receptor assays on breast carcinoma from mastectomy specimens

To determine whether autolytic loss of estrogen (ER) and progesterone (PgR) receptors might affect results of assays performed on primary carcinoma samples taken from fresh mastectomy specimens rather than from biopsy specimens, a group of 71 cases were examined, in which both types of samples were assayed. The comparisons showed a small significant reduction in the proportion of positive ER assay results in mastectomy-primary specimens compared with biopsy specimens, although the frequency of high-binding ER results in the mastectomy-primary specimens was not reduced. The number of positive PgR assays on mastectomy-primary specimens was not reduced in comparison with biopsy specimens. Correlation coefficients for ER values in the paired data were r = 0.836 for biopsy versus mastectomy, and r = 0.795 for primary tumor versus nodal metastasis. For PgR biopsy versus mastectomy r = 0.664, and for PgR primary versus node r = 0.352. The mean quantitative ER and PgR values were significantly higher in axillary lymph nodal metastases than in primary carcinomas, and the higher nodal receptor levels were explained in part by significantly higher tumor cellularity. It is concluded that while loss of ER sufficient to cause a false-negative interpretation may possibly occur in a few cases during the course of mastectomy, as a general rule, significant losses do not occur. The performance of assays on axillary metastases in mastectomy specimens is advantageous because of their high cellularity.