KLK3 and prostate cancer: The aim of the study was to assess the role of environmental exposure to these elements in prostate cancer and to evaluate their impact on the serum PSA and the parameters of oxidative stress: total oxidative stress (TOS), total antioxidant status (TAS), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx), advanced oxidation protein products (AOPP), and total sulfhydryl (SH) group levels in the prostate cancer patients.