Comparison of immunocytochemical and biochemical assays for estrogen receptor in fine needle aspirates and histologic sections from breast carcinomas.

An immunocytochemical assay using a monoclonal antibody specific for estrogen receptor (ER-ICA) was performed on needle aspirates and on histologic sections (mastectomy and biopsy specimens) from 55 patients with breast cancer. A total of 82 ER-ICAs were performed, with matched cytologic and histologic specimens in 27 patients, cytology alone in 15, and histology alone in 13. ER-ICA results were described by a histochemical score (H score) based on intensity-weighted percentages of staining cells. The H scores were compared with results of sucrose density gradient (SDG) analysis of histologic specimens (mastectomy, resection, or biopsy). An H score greater than or equal to 10 and an SDG value greater than or equal to 10 fmol/mg protein were considered positive. The sensitivity of cytologic ER-ICA was 94%, the specificity 100%. The sensitivity of histologic ER-ICA was 67%, the specificity 90%. Correlating cytologic H score with Black's nuclear grade showed that grade 1 (the most anaplastic) carcinomas demonstrated the lowest H scores (mean, 7.3 +/- 29.8), whereas the highest H scores were noted in grade 3 tumors (mean, 150.0 +/- 88.1). Both SDG and ER-ICA showed ER values to be lower in premenopausal than postmenopausal women. There was no correlation between H score and presence of axillary nodal metastases or tumor size. An overall good correlation was demonstrated between immunohistochemical methods and biochemical analysis.