Demonstration of estrogen receptors by monoclonal antibody in formalin-fixed breast tumors

An immunohistochemical technique using a commercially available monoclonal antibody to the estrogen receptor in formalin-fixed breast tumors is described. The author's technique is compared to three other recently published techniques in 27 case studies. The authors' method using pronase enzyme pretreatment and alkaline phosphatase as the third antibody yielded the best results. Comparison with the standard dextran-coated charcoal cytosolic assay results from the cases selected yielded a 100% sensitivity and 89% specificity for the authors' technique. The advantages of the immunohistochemical method over the biochemical assay are discussed and clinical implications are suggested. A step-by-step procedure for the authors' technique follows the text.