KLK3 and Familial prostate cancer: Here, we apply a PRS1 to these cohorts to determine whether it is predictive of prostate cancer death either alone or above and beyond blood markers collected many years before prostate cancer was diagnosed8,9: PSA or the 4Kscore, a commercially available pre-specified model based on four kallikrein markers used to inform biopsy decision-making in men with elevated PSA10.