Clinical studies have found that PSA may continue to rise in the early stage of docetaxel-based chemotherapy for some prostate cancer patients, but the clinical symptoms and imaging manifestations show a stable or improved trend, thereafter PSA shows a downward trend in the subsequent treatment, which is called “PSA flare”.[7] However, after 5 chemotherapy courses, the PSA was still rising rapidly. This evidence concerns the gene KLK3 and prostate cancer.