Serum proteomic mass spectra were analyzed to reveal a pattern discriminating between patients without (PSA < 1 ng/mL) and with prostate cancer (PSA > 4 ng/mL), and the results indicated that serum proteomic patterns could be of value for whether to proceed with a biopsy on patients with elevated PSA levels. The gene discussed is KLK3; the disease is Familial prostate cancer.