ESR1 and breast cancer: Also, 4-hydroxytamoxifen (but not tamoxifen), genistein and daidzein (but not genistin), curcumin, taxifolin, retinoic acids (e.g., all-trans and 9-cis) and dexamethasone up-regulated expression of p27 in estrogen receptor-positive human MCF7 breast cancer cells in vitro [10].