KLK3 and prostate cancer: Higher levels of PSMA of up to 1000-fold have been detected in secretory cells of prostate cancer (PCa) in the epithelium, and from several studies it emerged that there is a correlation with high Gleason scores, high serum levels of prostate specific antigen (PSA), advanced stages of disease and metastatic castration-resistant PC (mCRPC) [2,3,4].