The oestrogen receptors (ERα and ERβ) and their role in breast cancer: a review

One of the main prognostic markers measured in breast tumours is oestrogen receptor (ER) status. With the discovery of ERβ, it has been necessary to re-evaluate ER signalling and the role of ER in breast cancer. Preliminary reports on ERβ signalling suggest it might induce opposite effects to those of ERα. To further understand the biology of breast cancer, the role each ER plays in disease progression must be established. This review summarizes the current understanding of ERβ and discusses some of the published work on the role of ERα and ERβ in breast cancer.