title: Evidence of abnormal tyrosine phosphorylated proteins in the urine of patients with bladder cancer: the road toward a new diagnostic tool?
abstract: OBJECTIVE
  Since changes in protein phosphorylation are a common feature of cancer cells, we analyzed phosphoproteins in the tissue and urine of patients with bladder cancer and assessed the diagnostic relevance of abnormally phosphorylated proteins as tumor markers.
  
  
  METHODS
  Enrolled in this study were 66 patients and 82 healthy volunteers. From the first 14 patients with bladder cancer we obtained samples of malignant and normal bladder tissue. All patients and volunteers provided a urine sample. Protein extracts of tissue specimens were separated by 2-dimensional gel electrophoresis for comparative analysis of neoplastic and normal tissue. Phosphoproteins were studied by Western blot and characterized by mass spectrometry. Urine samples were analyzed by 1-dimensional gel electrophoresis. Phosphoproteins were measured by affinity dot blotting.
  
  
  RESULTS
  Profound changes in the pattern of protein tyrosine phosphorylation were consistently, reproducibly observed in bladder cancer tissues. A total of 24 phosphorylated proteins were differentially expressed in cancer tissue and identified by mass spectrometry. Phosphoproteins were fairly stable in urine samples, leading to accumulation. Urinary tyrosine phosphoproteins showed the most remarkable changes in patients with cancer with an approximately 5-fold increase compared to levels in healthy controls.
  
  
  CONCLUSIONS
  To our knowledge we investigated for the first time the diagnostic potential of tissue and urinary tyrosine phosphoproteins for bladder carcinoma. Results indicate that phosphorylated proteins may represent a new, valuable class of urinary biomarkers for bladder cancer.
authors.affiliation: Research Center for Experimental Medicine, University of Turin Medical School, Turin, Italy.
authors.forename: Amina
authors.initials: A
authors.lastname: Khadjavi
authors.forename: Giovanna
authors.initials: G
authors.lastname: Barbero
authors.forename: Paolo
authors.initials: P
authors.lastname: Destefanis
authors.forename: Giorgia
authors.initials: G
authors.lastname: Mandili
authors.forename: Giuliana
authors.initials: G
authors.lastname: Giribaldi
authors.forename: Franca
authors.initials: F
authors.lastname: Mannu
authors.forename: Antonella
authors.initials: A
authors.lastname: Pantaleo
authors.forename: Carlo
authors.initials: C
authors.lastname: Ceruti
authors.forename: Andrea
authors.initials: A
authors.lastname: Bosio
authors.forename: Luigi
authors.initials: L
authors.lastname: Rolle
authors.forename: Francesco
authors.initials: F
authors.lastname: Turrini
authors.forename: Dario
authors.initials: D
authors.lastname: Fontana
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000652:urine*; D001706:Biopsy; D015153:Blotting, Western; D016022:Case-Control Studies; D004587:Electrophoresis, Agar Gel; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D013058:Mass Spectrometry; D009367:Neoplasm Staging; D010766:Phosphorylation; D012372:ROC Curve; D014443:Tyrosine / Q000652:urine*; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery / Q000652:urine*
chemical_list: D014408:Biomarkers, Tumor; D014443:Tyrosine