Components of the uPA system such as u-PA, plasminogen activator inhibitor-1 (PAI-1) and urokinase-type plasminogen activator receptor (uPAR) are overexpressed in a variety of cancer types, most notably in breast cancer (22), but also in lung cancer (17,23) and malignant mesothelioma (18,24) and correlate with cancer progression, metastasis and poor prognosis. This evidence concerns the gene PLAU and breast cancer.