KLK3 and prostate carcinoma: The introduction of routine prostate specific antigen (PSA) testing was associated with increases in the number of men diagnosed with and treated for prostate cancer in the U.S. [1] For example, for every 100,000 men aged 66–74 receiving PSA testing in the US in 2007, an additional 4,894 men underwent prostate cancer biopsy, and 1,597 were treated [2].