Nevertheless, PSA screening often triggers biopsies of the prostate, most often performed by needle biopsy which has a false-negative rate of 10%–20%.21,22 Increasing the number of samples obtained increases the detection rate, yet some significant cancers might be missed.23,24 On the other hand, increasing the number of cores sampled leads to greater proportions of low-risk cancers detected. This evidence concerns the gene KLK3 and cancer.