title: The specificity of urinary aquaporin 1 and perilipin 2 to screen for renal cell carcinoma.
abstract: OBJECTIVE
  Renal cancer is frequently asymptomatic until late stages of the disease and it has a poor prognosis when not discovered early. AQP1 and PLIN2 are recently discovered, sensitive urine biomarkers of clear cell and papillary kidney cancer. We validated these biomarkers in a second cohort of patients and determined the effect of common kidney diseases on specificity.
  
  
  METHODS
  Urine samples were obtained from 36 patients with clear cell or papillary kidney cancer, 43 controls, 44 patients with documented urinary tract infection, 24 diagnosed with diabetic nephropathy and 18 diagnosed with glomerulonephritis. Urine levels of AQP1 and PLIN2 normalized to urine creatinine were determined by a sensitive, specific Western blot procedure.
  
  
  RESULTS
  Compared with controls, urine AQP1 and PLIN2 levels in patients with kidney cancer were 23-fold and fourfold greater, respectively, and they decreased 83% to 84% after tumor excision. There was a linear correlation between urine AQP1 and PLIN2 levels, and tumor size (each p <0.001). Urine AQP1 and PLIN2 levels in patients with kidney cancer were 11 to 23-fold and 17 to 25-fold greater, respectively, than in patients with the common kidney diseases.
  
  
  CONCLUSIONS
  The ability of urine AQP1 and PLIN2 to identify patients with kidney cancer compared to controls was validated in a second cohort of patients. Common kidney diseases do not adversely increase urine AQP1 and PLIN2 levels or decrease their specificity to screen for renal cancer.
authors.affiliation: Division of Clinical and Translational Research, Department of Anesthesiology, Siteman Cancer Center, Washington University in St. Louis (EDK), St. Louis, Missouri 63110-1093, USA. morrisse@wustl.edu
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Morrissey
authors.forename: Evan D
authors.initials: ED
authors.lastname: Kharasch
mesh_terms: D051398:Aquaporin 1 / Q000652:urine*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000652:urine*; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000652:urine*; D008297:Male; D008565:Membrane Proteins / Q000652:urine*; D000070780:Perilipin-2; D012680:Sensitivity and Specificity
chemical_list: D008565:Membrane Proteins; C000602982:PLIN2 protein, human; D000070780:Perilipin-2; D051398:Aquaporin 1