Utility of Kallikrein-Related Peptidases (KLKs) as Cancer Biomarkers

(KLK) family consists of 15 highly conserved serine pro-teases, which are encoded by the largest uninterrupted cluster of protease genes in the human genome. To date, several members of the family have been reported as po-tential cancer biomarkers. Although primarily known for theirbiomarkervalue inprostate,ovarian, andbreast can-cers, more recent data suggest analogous roles of KLKs in several other cancers, including gastrointestinal, head and neck, lung, and brainmalignancies. Among the proposed KLK cancer biomarkers, prostate-specific antigen (also known as KLK3) is the most widely recognized member in urologic oncology. CONTENT: Despite substantial progress in the under-standing of the biomarker utility of individual KLKs, the current challenge lies in devising biomarker panel