title: Urine screening by Seldi-Tof, followed by biomarker identification, in a Brazilian cohort of patients with renal cell carcinoma (RCC).
abstract: OBJECTIVE
  To screen proteins/peptides in urine of Renal Cell Carcinoma (RCC) patients by SELDI-TOF (Surface Enhanced Laser Desorption Ionization - Time of Flight) in search of possible biomarkers.
  
  
  METHODS
  Sixty-one urines samples from Clear Cell RCC and Papillary RCC were compared to 29 samples of control urine on CM10 chip. Mass analysis was performed in a ProteinChip Reader PCS 4,000 (Ciphergen Biosystems, Fremont, CA) with the software Ciphergen Express 3.0. All chips were read at low and at high laser energy. For statistical analysis the urine samples were clustered according to the histological classification (Clear Cell and Papillary Carcinoma). For identification urine was loaded on a SDS PAGE gel and bands of most interest were excised, trypsinized and identified by MS/MS. Databank searches were performed in Swiss-Prot database using the MASCOT search algorithm and in Profound.
  
  
  RESULTS
  Proteins that were identified from urine of controls included immunoglobulin light chains, albumin, secreted and transmembrane 1 precursor (protein K12), mannan-binding lectin-associated serine protease-2 (MASP-2) and vitelline membrane outer layer 1 isoform 1. Identification of immunoglobulins and isoforms of albumin are quite common by proteomics and therefore cannot be considered as possible molecular markers. K12 and MASP-2 play important physiological roles, while vitellite membrane outer layer 1 role is unknown since it was never purified in humans.
  
  
  CONCLUSIONS
  The down expression of Protein K-12 and MASP-2 make them good candidates for RCC urine marker and should be validated in a bigger cohort including the other less common histological RCC subtypes.
authors.affiliation: Applied Genetic Laboratory, Hematology Division, National Institute of Cancer, Rio de Janeiro, RJ, Brazil.
authors.forename: Gilda
authors.initials: G
authors.lastname: Alves
authors.forename: Denise A
authors.initials: DA
authors.lastname: Pereira
authors.forename: Vanessa
authors.initials: V
authors.lastname: Sandim
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Ornellas
authors.forename: Niko
authors.initials: N
authors.lastname: Escher
authors.forename: Christian
authors.initials: C
authors.lastname: Melle
authors.forename: Ferdinand
authors.initials: F
authors.lastname: von Eggeling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000652:urine*; D001938:Brazil; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000652:urine*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000652:urine*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D040901:Proteomics / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor