Monoclonal antibody staining and impact of surgical technique on the identification and quantitation of steroid receptors in human breast cancer.

In this prospective study of 31 patients, paired receptor levels from biopsy and mastectomy specimens were found to be significantly correlated on biochemical assay. Despite this fact, 6 of 20 tumors that were estrogen receptor-positive on biopsy, had a negative assay from the mastectomy specimen, indicating the need for a fresh tumor specimen. Immunocytochemical staining with monoclonal antibody H222 Spy, an antibody specific for the estrogen receptor, was evaluated in 34 biopsy and mastectomy specimens. With a sensitivity of 85 percent and specificity of 93 percent, this technique compares favorably with the standard biochemical assay.