Multi-center prospective study in which blood samples will be taken from 1500 male patients aged between 21–80 scheduled for prostate biopsy. Analysis of cell-free cancer DNA extracted from these samples will be undertaken to determine whether copy number instability scores derived from the cfDNA correlates with PSA screening levels and prostate biopsy results (i.e., Gleason score) in these patients. This evidence concerns the gene KLK3 and cancer.