It has been known for over two decades that overexpression of the serine protease urokinase plasminogen activator (uPA) and its receptor uPAR contributes to the aggressive phenotype in a number of cancers such as breast (both invasive and non-invasive), lung, and gastrointestinal tumors and their metastases, and that this expression is not observed in non-diseased tissue [1,2,3,4,5,6]. This evidence concerns the gene PLAU and cancer.