title: Circulating growth factor levels are associated with tumorigenesis in neurofibromatosis type 1.
abstract: OBJECTIVE
  Neurofibromatosis type 1 (NF1) is characterized by systemic development of neurofibromas. Early clinical diagnosis can be ambiguous, and genetic diagnosis can be prohibitively difficult. Dysregulation of a number of growth factors has been suggested to be a mechanism of pathogenesis. This study was performed to assess the contribution of circulating growth factors for diffuse tumorigenesis and the diagnostic value of circulating growth factor identification in serum.
  
  
  METHODS
  The growth stimulation of neurofibroma-derived cells by serum from NF1 patients was tested, and serum growth factor levels in a cohort of NF1 patients (n = 39) between the ages of 7 and 70 years were analyzed.
  
  
  RESULTS
  Concentrations of midkine (MK) and stem cell factor, but not epidermal growth factor, were substantially increased in serum of NF1 patients when compared with healthy controls. Within the NF1 group, MK levels increased dramatically at puberty from an average of 0.79 ng/mL in patients <18 years to 1.18 ng/mL in patients >18 years old. Stem cell factor and MK concentrations above a defined threshold in serum of NF1 patients are of diagnostic benefit for 96% of patients in the cohort tested. Furthermore, serum from NF1 patients enhanced proliferation of human neurofibroma-derived primary Schwann cells and endothelial cells substantially better than normal serum.
  
  
  CONCLUSIONS
  Enhanced circulating growth factor levels contribute to diffuse tumorigenesis in NF1 and may provide the basis for molecular diagnosis.
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Mashour
authors.forename: Pablo Hernáiz
authors.initials: PH
authors.lastname: Driever
authors.forename: Melanie
authors.initials: M
authors.lastname: Hartmann
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Drissel
authors.forename: Tingguo
authors.initials: T
authors.lastname: Zhang
authors.forename: Bianca
authors.initials: B
authors.lastname: Scharf
authors.forename: Ursula
authors.initials: U
authors.lastname: Felderhoff-Müser
authors.forename: Sadatoshi
authors.initials: S
authors.lastname: Sakuma
authors.forename: Reinhard E
authors.initials: RE
authors.lastname: Friedrich
authors.forename: Robert L
authors.initials: RL
authors.lastname: Martuza
authors.forename: Victor Felix
authors.initials: VF
authors.lastname: Mautner
authors.forename: Andreas
authors.initials: A
authors.lastname: Kurtz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016207:Cytokines / Q000097:blood*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000097:blood*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D000078792:Midkine; D009456:Neurofibromatosis 1 / Q000097:blood* / Q000473:pathology*; D012583:Schwann Cells / Q000166:cytology / Q000378:metabolism; D019089:Stem Cell Factor / Q000097:blood*
chemical_list: D016207:Cytokines; D019089:Stem Cell Factor; D000078792:Midkine; D004815:Epidermal Growth Factor