Furthermore, the high number of 94% of PET-positive patients with biochemical recurrence having a PSA ≤ 0.1 ng/ml after 20 months in our cohort compares nicely to the analysis of Zschaeck et al. [22] on 20 recurrent high-risk prostate cancer patients with a median PSA of 0.15 ng/ml after a median follow-up of 29 months. This evidence concerns the gene KLK3 and prostate cancer.