Present status of estrogen-receptor immunohistochemistry.

Anti-estradiol is used as the primary antibody in the peroxidase-anti-peroxidase (PAP) immunoperoxidase (IP) method to visualize putative estrogen-binding sites in potential hormone-dependent tissues and tumours. Basically, 2 different methods are used. The 1st is carried out on fresh-frozen cryostat sections; the 2nd has the advantage to be applicable on current laboratory material, i.e. formalin-fixed and paraffin-embedded material. The various steps of both techniques are analyzed and compared: the potential influence of tissue processing, the necessity of preincubation in estrogens, the physico-chemical conditions of incubation, and the specificity of controls. Van Bogaert (1983) analyzed the drawbacks of the presently available cytochemical techniques used to stain putative estrogen binding sites (EBS) in human breast cancer. In the present paper, a similar investigation is carried out with the aim to evaluate both the technical advantages and possible pitfalls of immunohistochemistry of estrogen receptors (ER) in human mammary carcinoma.