The effectiveness of phytoestrogens, which exist in nature not as single compounds but as complex mixtures in food matrices, as therapeutic agents for existing diseases is still unclear, but epidemiological studies indicate diets containing a significant amount of phytoestrogens seem to correlate with ERβ-mediated benefits (such as decreased incidence of breast and prostate cancers). The gene discussed is ESR2; the disease is Familial prostate cancer.