[Chemoprevention for Prostate Cancer-The Potential of Angiotensin Ⅱ Receptor Blocker].

In Japan, the incidence of prostate cancer(Pca)has been increasing mainly due to the early detection system by PSA screening. Considering pharmacoepidemiology, the statins and metformin have been recognized to lower the risk of incidence of Pca. Excessive intake of calcium, multivitamin and vitamin E increased the Pca risk. The 5-alpha-reductase inhibitors( 5ARIs)are widely used in the treatment of benign prostatic hyperplasia(BPH)by biological function of inhibiting the conversion from testosterone to dihydrotestosterone. A systematic review and meta-analysis identified that 5ARIs had no impact on overall mortality and Pca-related mortality, nor on high-grade Pca diagnosis. The use of anti-hypertensive drugs was reportedly associated with an increasing risk of Pca. However, as an effect of post diagnostic use of anti-hypertensive drugs, angiotensin Ⅱ receptor blockers(ARBs)was associated with improved overall survival and cause specific survival, which means the second chemoprevention potential for Pca. Our previous investigation demonstrated ARBs can suppress the expression of androgen receptor and affect the proliferative signal transduction system in Pca cells. Based on additional data of our experiment, we confirmed the anti-tumor effect of ARBs for Pca, and further clinical trials to make sure the chemoprevention for pre-diagnostic Pca is needed in future.