Estrogen Receptor (ER)

This antibody recognizes a protein of 67kDa, which is identified as estrogen receptor (ER). ER content of breast cancer tissue is an important parameter in the prediction of prognosis and response to endocrine therapy. This antibody strongly stains the nucleus of epithelial cells in breast carcinomas. The ER is an important regulator of growth and differentiation in the mammary gland. Presence of ER in breast tumors indicates an increased likelihood of response to anti-estrogen (e.g. tamoxifen) therapy.