Recently, prostate cancer antigen 3 (PCA3), which is based on the quantification of both PCA3 and PSA mRNA expression in urine samples, has been shown to outperform PSA in identifying patients at risk for PCa at the first biopsy and to be useful in predicting the outcome of re-biopsy after the first biopsy [5]. The gene discussed is KLK3; the disease is posterior cortical atrophy.