Soluble form of carbonic anhydrase IX (CAIX) in transitional cell carcinoma of urinary tract

Neoplasma. 2009;56(4):298-302. doi: 10.4149/neo_2009_04_29.


We investigated the expression of cell-associated CAIX protein in histological sections of the transitional cell carcinoma (TCC) of the urinary tract and of the soluble form of CAIX (s-CAIX) shed by the tumor into the serum and urine of TCC patients. A total of 23 patients with histologically confirmed TCC or squamous cell carcinoma (SCC) were enrolled in the pilot study. Sixteen healthy individuals served as controls. Membrane-bound CAIX was present in the tumor cells near the endoluminal surface. Necrosis was observed in only 4 samples. Using Western blots, s-CAIX concentrated from urine was visualized as a double band at 50 and 54 kDa. In most cases, the presence of s-CAIX in the urine correlated with CAIX expression in the tumor. On the other hand, s-CAIX did not exceed the normal level in the serum of TCC patients. Urine from patients with TCC of the urinary bladder and renal pelvis contained s-CAIX, allowing the detection of tumors in approximately 70% of the patients. Moreover, two additional patients with suspected, but unconfirmed bladder tumor, with s-CAIX detected in urine, developed tumors identified as TCC within six months. We suggest that after a simple, rapid and sensitive test, monitoring s-CAIX levels in urine will be developed, it may be useful for early detection of relapse in patients following transurethral tumor resection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, Neoplasm / metabolism*
  • Biomarkers, Tumor / metabolism*
  • Blotting, Western
  • Carbonic Anhydrase IX
  • Carbonic Anhydrases / metabolism*
  • Carcinoma, Transitional Cell / blood
  • Carcinoma, Transitional Cell / enzymology*
  • Carcinoma, Transitional Cell / urine
  • Case-Control Studies
  • Cell Membrane / enzymology
  • Cell Membrane / pathology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Immunoenzyme Techniques
  • Kidney Pelvis / enzymology*
  • Kidney Pelvis / pathology
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Pilot Projects
  • Prognosis
  • Urinary Bladder / enzymology*
  • Urinary Bladder / pathology
  • Urologic Neoplasms / blood
  • Urologic Neoplasms / enzymology*
  • Urologic Neoplasms / urine
  • Young Adult


  • Antigens, Neoplasm
  • Biomarkers, Tumor
  • CA9 protein, human
  • Carbonic Anhydrase IX
  • Carbonic Anhydrases