Analysis of Estrogen and Progesterone Receptors in Breast Carcinoma: Comparison of immunocytochemical assay with biochemical dextran-coated charcoal assay

Ko, Ill Hyang; Park, Kyeong Mee

Abstract

Estrogen receptor(ER) is a soluble form of hormone receptor protein which is located in the nucleus and cytoplasm of a cell is found in 60% of cases of the cells of breast carcinoma. Fifty to sixty percent of ER positive breast carcinoma responds to antihormone therapy wheres the response rate is only 5% in ER negative tumors. Currently, the ER assay has become a standard index in the management and prediction of the prognosis of advanced breast carcinoma. Semiquantitative biochemical assay, dextran-coated charcol(DCC) assay, to measure ER from fresh tissue was first developed by Korenman in 1970 using isotope-labled ertradiol, has been widely utilized. In 1978, Kurzon newly developed immunocytochemical assay(ICA) employing monoclonal antibody against those hormone receptors to detect intracellular localization of ER and progesterone receptor (PR). The results of the assay have been reported by many investigators thereafter. The purpose of this study was to evaluate the hormonal receptors with a monoclonal antibody using an immunoperoxidase procedure to detect both estrogen and progesterone receptors (ER-immunocytochemical assay:ER-ICA and PR-immunocytochemical assay:PR-ICA) in 59 cases of paraffin embedded sections from formalin-fixed and routinely processed breast carcinoma tissue. Concomitantly, fine-needle aspiration biopsy cytology of the breast cancer from 29 women were assayed for ER/PR receptors. Results were compared with quantitative biochemical values determined from dextran-coated charcoal(DCC) assay on the fresh tumor tissue obtained subsequently from the surgery. ER-ICA showed positive result in 22 out of 36 DCC-positive cases(sensitivity, 61.1%) and negative in 23 out of 23 DCC-negative cases (specificity, 100.0%). PR-ICA was positive in 33 out of 35 DCC-positive cases(sensitivity, 94.3%) and negative in 16 out of 24 DCC-negative cases(specificity, 66.7%). The value of ER-ICA or PR-ICA positivity were roughly correlated with the concentration of ER/PR receptors analyzed by DCC method. The results of both methods were correlated with the nuclear grade of the tumor(ICA:p=0.002, DCC: p=0.015) but were not correlated with histologic grade(ICA: p=0.323, DCC: p=0.0164). ER-ICA positivity was correlated with lower incidence of axillary node metastasis (p=0.021) but no significant correlation between PR-ICA positivity and node metastasis(p=0.171). Both ER/PR-ICA positivity were not correlated with age(p=0.924) and tumor size(p=0.663). The score of ICA particularly ER was proportional to DCC level(ER: r=0.5, p=0.000, PR: r=0.2, p=0.000). ICA concordance with DCC of ER and PR were 76.3% and 83.1%, respectively. The concordance of PR-ICA and DCC was proportional but was statistically less significant. In aspiration biopsy cytology the concordance of ER/PR-ICA and DCC were 72.4% and 65.5%, respectively. Immunocytochemical staining to identify ER/PR receptors from the tissue of breast carcinoma would be tested as a mean to substitute for the conventional DCC method.