Thus, a search for new biomarkers which could be more specific for the detection of prostate cancer is needed. The use of biomarkers such as percent free PSA (Lee, 2006), intact serum PSA (Steuber, 2002), serum pro-PSA(Lein, 2005) and kallikrein (Stephan, 2000) have shown to be useful in the detection of prostate cancer. However, although a biomarker could improve the precision of screening it is possible that in clinical practice it is not viable, for the need of fresh samples or high costs (Villanueva, 2006). The use of PSA velocity has been suggested, an increase of more than has been associated with an increased risk of.
