Presence of urokinase-type plasminogen activator receptor in urine of cancer patients and its possible clinical relevance.

High levels of urokinase-type plasminogen activator receptor (uPAR) are expressed in various types of cancer. Recent studies showed that cancer patients may have increased levels of soluble (s)uPAR in their serum. In the present study, we show that urine samples from healthy volunteers contain measurable amounts of suPAR. suPAR/creatinine levels from healthy controls showed only little variation over the day and were even stable during a month of continued monitoring. Importantly, urinary suPAR/creatinine levels were highly correlated with serum suPAR concentrations. Urinary suPAR levels were elevated in patients with different types of cancer. Interestingly, part of the urinary suPAR seemed to be present in a cleaved form, as has been found in tumor tissue extracts. Together with the recently established, cell migration-promoting effect of certain cleaved fragments of suPAR, the present data suggest that the measurement of urinary suPAR and/or its cleaved forms might have clinical implications.