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Disease Markers
Volume 2014 (2014), Article ID 135649, 6 pages
Research Article

Aquaporin-1 Protein Levels Elevated in Fresh Urine of Renal Cell Carcinoma Patients: Potential Use for Screening and Classification of Incidental Renal Lesions

1Department of Urology, Emory University, 1365 Clifton Road NE, Clinic B 4221, Atlanta, GA 30322, USA
2Atlanta VA Medical Center, 1670 Clairmont Rd, Decatur, GA 30033, USA
3Department of Medicine, Emory University, 1525 Clifton Road, 423 Atlanta, GA 30322, USA

Received 28 June 2013; Revised 26 February 2014; Accepted 12 March 2014; Published 6 April 2014

Academic Editor: Mark M. Kushnir

Copyright © 2014 Shilpa Sreedharan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Introduction and Objectives. There are over 65,000 new cases of renal cell carcinoma (RCC) each year, yet there is no effective clinical screening test for RCC. A single report claimed no overlap between urine levels of aquaporin-1 (AQP1) in patients with and without RCC (Mayo Clin Proc. 85:413, 2010). Here, we used archived and fresh RCC patient urine to validate this report. Methods. Archived RCC, fresh prenephrectomy RCC, and non-RCC negative control urines were processed for Western blot analysis. Urinary creatinine concentrations were quantified by the Jaffe reaction (Nephron 16:31, 1976). Precipitated protein was dissolved in 1x SDS for a final concentration of 2 μg/µL creatinine. Results. Negative control and archived RCC patient urine failed to show any AQP1 protein by Western blot analysis. Fresh RCC patient urine is robustly positive for AQP1. There was no signal overlap between fresh RCC and negative control, making differentiation straightforward. Conclusions. Our data confirms that fresh urine of patients with RCC contains easily detectable AQP1 protein. However, archival specimens showed an absence of detectable AQP1 indistinguishable from negative control. These findings suggest that a clinically applicable diagnostic test for AQP1 in fresh urine may be useful for detecting RCC.