KLK3 and prostate cancer: In 2001, the proportion of elderly increased to 14.3% and the crude incidence rate for prostate cancer was 74.5.3,4 The dramatic increase in the incidence of prostate cancer over the past two decades is not due to any newly identified risk factor, but rather to the increasing use of the prostate-specific antigen (PSA) test in healthy men and therefore detection of a large number of cancers that would have otherwise remained undetected for life.