Do Soy Isoflavones Provide Protection Against Prostate Cancer Via a Classical Estrogen Receptor-Alpha (Era) Independent Mechanism?
Male populations, which consume soy foods as a major component of their diet, have reduced incidence of prostate cancer. Our hypothesis is that soy isoflavones, specifically genistein and daidzein, will provide protection from development and progression of prostate cancer in mice lacking functional estrogen receptor-alpha protein and containing the PBTag transgene (TRAMP mice) to establish whether ER-alpha or ER-beta pathways are involved. The latency of tumor development, tumor size and number, biochemical markers, and histological features are being determined on selected tumors to characterize the progression from normal prostate to neoplastic and metastatic prostate cancer. Unexpectedly we have found that high concentrations of genistein are not protective but actually “promote” prostate cancer in the ERalpha-wild type/TRAMP mouse model. Others have reported that low levels of genistein may be protective in this model. We are currently re-examining the role of ERalpha in this proc