Research progress of flavonoids targeting estrogen receptor in the treatment of breast cancer

Breast cancer (BC) stands as the most prevalent malignancy among women. Targeting the estrogen receptor (ER) or ER pathway is one of the important approaches for ER⁺ BC treatment. As a class of phytoestrogens, flavonoids possess notable anti-tumor properties and hold immense potential in regulating ER signaling. In this review, we reported the recent advances in both in vitro and in vivo studies of flavonoids and their synthetic derivatives targeting the ER signaling pathway, including the target and mechanism of action of these molecules, as well as their structure–activity relationship. Based on the available literature, the beneficial effects of flavonoids as ER targeting agents are promising but they require further in vitro and in vivo studies to enable its translation from bench to bedside. This review will provide valuable guidance and insights for the future development of drugs targeting the ER pathway.