Two previous studies using data from the European Randomized Study of Screening for Prostate Cancer in Rotterdam and Göteborg showed an improvement in the AUC for a base model of total PSA and age compared with a model additionally including free PSA, intact PSA and hK2, from 0.64 to 0.76 and 0.68 to 0.83, respectively (10, 11). This evidence concerns the gene HK2 and prostate cancer.