KLK3 and prostate cancer: Owing to the widespread prevalence of malignant neoplasm of the prostate in men, several scientific and medical research investigations have focused on the development of simple, rapid, affordable, and accurate PSA-based-methods for early prostate cancer diagnosis, including electrochemical and fluorometric methods [14,15,16,17,18,19,20,21,22,23,24,25,26].