title: Serum protein profiling to identify high-risk neuroblastoma: preclinical relevance of blood-based biomarkers.
abstract: BACKGROUND
  Development of early detection assays for advanced stage neuroblastoma (NB) remains elusive. We have previously shown that serum protein profiling technologies can differentiate healthy from NB children. As various sources of patient related bias exist in serum proteins, we hypothesized a well controlled animal model may provide a better method to identify tumor blood-based markers during NB progression.
  
  
  METHODS
  Tumors were induced in the left kidneys of nude mice by the injection of cultured human NB cells (10(6)). Sera were collected from control and tumor-bearing mice at 2, 4, and 6 wk. Albumin-depleted sera were subjected to comparative proteomic profiling using 2D gel electrophoresis. Paired samples at each time point were analyzed and differentially expressed serum proteins were identified by mass spectrometry. Additionally, sera proteomic analysis from children with Stage IV NB and healthy controls were performed.
  
  
  RESULTS
  Overexpression of five mouse serum proteins [alpha(1)-acid glycoprotein, alpha(1)-antitrypsin, alpha(2)-macroglobulin, serum amyloid P-component, and serum amyloid A) were found only in NB-bearing mice. Changes in protein abundance were found to increase 2.5-fold (P < or = 0.05) between 2-, 4-, and 6-wk old mice. Underexpression of immunoglobulin kappa chain constant region was observed in the sera of tumor bearing mice compared with controls (2.5-fold, P < or = 0.05). Among NB patients, alpha(1)-acid glycoprotein, apolipoprotein A-IV, haptoglobin, and serum amyloid A were found to be up-regulated.
  
  
  CONCLUSIONS
  We identified distinct acute phase proteins that show up-regulation in both an animal tumor model and high-risk NB patients. As these serum proteins have been recognized as markers of tumor progression and prognosis in human malignancies, the validation of these polypeptides may enable serum proteomic profiling to become a valuable tool for identifying high-risk NB.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, Indiana, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Sandoval
authors.forename: Katharyn E
authors.initials: KE
authors.lastname: Turner
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Hoelz
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Rescorla
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hickey
authors.forename: Linda H
authors.initials: LH
authors.lastname: Malkas
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood*; D001932:Brain Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D045744:Cell Line, Tumor; D002648:Child; D042241:Early Diagnosis; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D007668:Kidney; D013058:Mass Spectrometry; D051379:Mice; D008819:Mice, Nude; D009367:Neoplasm Staging; D009368:Neoplasm Transplantation; D009447:Neuroblastoma / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D040901:Proteomics / Q000379:methods*; D012307:Risk Factors; D014183:Transplantation, Heterologous
chemical_list: D014408:Biomarkers, Tumor