KLK3 and prostate cancer: Although the early diagnosis is more feasible due to the recent improvement of prostate-specific antigen (PSA) measurement, which improves the overall survival of prostate cancer patients, however, for the 15% of prostate cancer patients categorized as high-risk prostate cancer, 30–60% of them at around 10 years would eventually have metastasis with 10–25% patients dying of metastasis.