Urinary matrix metalloproteinase activity is not significantly altered in patients with renal cell carcinoma.
OBJECTIVE
Matrix metalloproteinases (MMPs) are proteins that degrade the extracellular matrix and have been shown to be elevated in the urine of patients with cancer. One action of MMPs is the degradation of collagen IV that plays a role in tumor invasion and metastasis. This degradation can be measured by a fluorescent microplate activity assay that has been suggested to identify patients with renal cell carcinoma (RCC). Our aim was to confirm the utility of urinary MMP activity as a diagnostic test for RCC.


METHODS
Urine samples from 21 patients undergoing nephrectomy for renal masses, as well as from 2 patients undergoing retroperitoneal mass excision for presumed local recurrence, were collected. Urine samples from 47 healthy volunteers were also collected. After concentration, the urine samples were incubated with fluorescein-labeled collagen IV. The fluorescence activity in each sample was measured using a conventional fluorescent microplate reader to determine the degree of collagen IV degradation in each specimen.


RESULTS
Of the 21 patients undergoing nephrectomy, 15 had RCC, and both patients undergoing retroperitoneal mass excision had pathologically confirmed RCC recurrence. The mean number of fluorescence units emitted from the urine of patients with RCC was 48,924 units (range 0 to 275,879). The mean number of fluorescence units emitted from the urine of healthy patients was 29,834 units (range 0 to 400,086). This difference was not statistically significant (P = 0.34).


CONCLUSIONS
Despite previous evidence, urinary MMP activity was not an adequate test to identify RCC. Most normal urine samples had significant MMP activity.
Cannon
Glenn M
GM
Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213-3232, USA. cannongm@upmc.edu
Getzenberg
Robert H
RH
D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000201:enzymology* / Q000652:urine*; D006801:Humans; D007680:Kidney Neoplasms / Q000201:enzymology* / Q000652:urine*; D020782:Matrix Metalloproteinases / Q000652:urine*; D008875:Middle Aged
D020782:Matrix Metalloproteinases