title: The impact of pre-analytical conditions on the serum proteome: heat-stabilization versus nitrogen storage.
abstract: BACKGROUND
  Biological material reflecting the in vivo composition of markers provides a high potential for biomarker discovery.
  
  
  OBJECTIVE
  We compared the serum proteome following heat- and nitrogen-preservation, with and without subsequent storage at room temperature.
  
  
  METHODS
  Serum samples were collected, treated and analysed by two-dimensional gel electrophoresis. Protein spots were identified and confirmed by two mass spectrometry approaches (MALDI & ESI) and subjected to Ingenuity Pathway Analysis.
  
  
  RESULTS
  We revealed 24 differentially expressed proteins (p ≤ 0.05) between nitrogen and heat preservation, and 87 between nitrogen and heat preservation with subsequent storage for 120 h at room-temperature. Mass spectrometry identified 25 polypeptides. Pathway analysis resulted in networks maintaining Cellular Assembly and Organization, Movement and Maintenance.
  
  
  CONCLUSIONS
  Heat-stabilization does not substantially change the short-term proteome composition of serum compared with nitrogen treatment. However, heat-stabilization alone seems insufficient for long-term sample preservation for serum samples. We identified transthyretin and apolipoprotein A-IV as sample quality markers.
authors.affiliation: Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Medical Center Schleswig-Holstein, Campus Lübeck, Germany. Gemoll@chirurgie.uni-luebeck.de
authors.forename: Timo
authors.initials: T
authors.lastname: Gemoll
authors.forename: Oliver
authors.initials: O
authors.lastname: Löwe
authors.forename: Mats
authors.initials: M
authors.lastname: Borén
authors.forename: Martina
authors.initials: M
authors.lastname: Oberländer
authors.forename: Sonja
authors.initials: S
authors.lastname: Hartwig
authors.forename: Stefan
authors.initials: S
authors.lastname: Lehr
authors.forename: Uwe J
authors.initials: UJ
authors.lastname: Roblick
authors.forename: Gert
authors.initials: G
authors.lastname: Auer
authors.forename: Hans
authors.initials: H
authors.lastname: Jörnvall
authors.forename: Jens K
authors.initials: JK
authors.lastname: Habermann
mesh_terms: D015415:Biomarkers / Q000097:blood; D001798:Blood Proteins / Q000032:analysis*; D003110:Colonic Neoplasms / Q000097:blood* / Q000175:diagnosis; D015925:Cryopreservation; D015180:Electrophoresis, Gel, Two-Dimensional; D006358:Hot Temperature; D006801:Humans; D009584:Nitrogen; D025341:Principal Component Analysis; D055550:Protein Stability; D040901:Proteomics / Q000592:standards*; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D009584:Nitrogen