||Acolbifene, also known as EM-652, or SCH-57068, is a selective estrogen receptor modulator (SERM). Acolbifene is currently being studied in the prevention of breast cancer in women at high risk of breast cancer. EM-652 is the compound having the highest affinity for the estrogen receptor, including estradiol. It has higher affinity for the ER than ICI 182780, hydroxytamoxifen, raloxifene, droloxifene and hydroxytoremifene. EM-652 was also the most potent inhibitor of the percentage of cycling cancer cells.