Previously, matriptase, an epithelial TTSP, was shown to activate growth factors, such as hepatocyte growth factor,53 macrophage stimulating protein 1,54 and members of the platelet‐derived growth factor family,55 which promote cancer progression by enhancing c‐Met–, PAR‐2–, RON– and PDGF receptor–mediated pathways. Here, ST14 is linked to cancer.