Where all individuals undergo PSA testing, like in ProtecT, high-grade tumors will be less affected by a possible effect of alcohol on PSA, since they are usually characterized by high levels of the marker.28 Also, in situations where not everyone is PSA tested, as is the case in many studies from the literature, detection bias is minimized for these tumor sub-types as they are more likely to progress to advanced and metastatic stage and become symptomatic quicker,29,30 and to be diagnosed regardless of PSA testing. This evidence concerns the gene KLK3 and neoplasm.