Abstract
Two oestrogen receptors (ERs), ERα and ERβ, have been identified. ERα is by far the better characterized and is an established predictive marker in breast cancer which influences decisions on whether or not to give adjuvant anti‐oestrogens, such as tamoxifen. In contrast, the function of ERβ in breast pathobiology is unclear, partly because most studies have focused on its mRNA rather than the protein. In this review, the significance of ERβ in the human breast is reviewed with respect to recent literature and its possible implications are discussed. Copyright © 2002 John Wiley & Sons, Ltd.