Soy isoflavones, estrogen therapy, and breast cancer risk

Soy isoflavones, estrogen therapy, and breast cancer risk: analysis and commentary

"Overall, there is little clinical evidence to suggest that isoflavones will increase breast cancer risk in healthy women or worsen the prognosis of breast cancer patients. Although relatively limited research has been conducted, and the clinical trials often involved small numbers of subjects, there is no evidence that isoflavone intake increases breast tissue density in pre- or postmenopausal women or increases breast cell proliferation in postmenopausal women with or without a history of breast cancer."

Nutr J. 2008 Jun 3;7:17.