However, the PSA concentration increases not only in PCa but also in some nonmalignant conditions, such as benign prostatic hyperplasia (BPH), prostatic hyperplasia, urinary tract infection, and indwelling catheters, especially among patients with PSA levels within the gray zone of 4 − 10 ng/mL [2]. This evidence concerns the gene KLK3 and benign prostatic hyperplasia.