Later analyses of the PCPT results have shown that the observed higher proportion of high-grade cancers in finasteride-treated men is due to detection bias caused by decreased prostate volume, increased sensitivity of PSA to detect prostate cancer and altered tumour grading in finasteride users (Thompson et al, 2006; Lucia et al, 2007; Pinsky et al, 2008). This evidence concerns the gene KLK3 and Familial prostate cancer.