Increased 16-OH estrone production is proposed to have significant estrogenic activity and an increased risk of breast cancer Increased 4-OH estrones also may enhance cancer development studies have shown that 4-OH estrone from equine (horse) estrogen, causes mutagenic damage 5 times more rapidly than normal 4-OH estrones. Equine estrogens, increase metabolism to 4-OH estrone The 2-OH estrone pathway is the pathway to metabolize estrogen to have a low cancer risk