摘要: The anti-oestrogen tamoxifen is the most commonly used treatment for patients with oestrogen-receptor (ER)-positive breast cancer. Although many benefit from in adjuvant and metastatic settings, resistance an important clinical problem. target of vivo ER. Over last decade advances have been made our understanding biology ER which may help to explain how develops. Such mechanisms include changes expression ERalpha or ERbeta, alterations co-regulatory proteins, influences cellular kinase signal transduction pathways. experimental evidence supporting these are discussed this review.