KLK3 and prostate cancer: In summary, epidemiological, laboratory and early phase clinical trials over the past two decades have demonstrated that formulations of GTC containing over 50% catechins in the form of EGCG administered to men at high risk or men with localized PCa, is bioavailable in plasma, reduces serum PSA, modulates proliferative and apoptotic intermediate endpoint biomarkers implicated in prostate carcinogenesis and the cumulative rate of progression to prostate cancer with no toxicities, including liver enzymes.