Towards a comprehensive database of proteins from the urine of patients with bladder cancer

Purpose: To establish a comprehensive two-dimensional database of proteins from the urine of patients with bladder cancer. Materials and Methods: Urines dialized against distilled H2O were freeze-dried and subjected to isoelectrofocusing two-dimensional gel electrophoresis. Coomassie brilliant blue stained dry gels were scanned and analyzed with the PDQUEST software. Proteins were identified by one or more of the following techniques: microsequencing (44 proteins), mass spectrometry, comigration and immunoblotting. Results: The urine protein database, which includes all the polypeptides detected in the urines of 50 patients, lists 339 proteins (including variants) of which 124 have been identified. Of these, psoriasin, the psoriasis-associated fatty acid binding protein 5, the gelsolin fragments and prostaglandin D2 synthetase have not been previously described. Conclusions: The database provides a solid basis for further studies aiming at identifying tumor markers in the urine that may serve as prognostic factors in bladder cancer.