KLK3 and benign prostatic hyperplasia: Elevated levels of PSA can be found in other pathologies (benign prostatic hyperplasia, and acute prostatitis) or in physiological conditions, such as age increase and sexual activity; (ii) PSA test lacks sensitivity because only 25% of patients with PSA of between 2.5 and 10 ng/ml, gray zone, show positive biopsies; and (iii) PSA is not indicative of tumor staging and grading alone.