KLK3 and ovarian cancer: The idea is to screen genome or proteome activity with microarray or mass spectrometry to find a panel of biomarkers (usually five to 20) and use them to build a diagnosis model that could outperform established single-protein biomarkers, such as PSA (Prostate Specific Antigen) for prostate cancer and CA-125 (Cancer Antigen) for ovarian cancer (Diamandis, 2004).