title: A comparison between stem cells from the adult human brain and from brain tumors.
abstract: OBJECTIVE
  To directly compare stem cells from the normal adult human brain (adult human neural stem cells [AHNSC]), Grade II astrocytomas (AC II), and glioblastoma multiforme (GBM), with respect to proliferative and tumor-forming capacity and differentiation potential.
  
  
  METHODS
  Cells were isolated from tissue obtained during epilepsy surgery (AHNSCs) or tumor surgery (glioma stem cells [GSC]). They were cultured and investigated in vitro or after transplantation in immunodeficient mice.
  
  
  RESULTS
  Under identical experimental conditions, the following were found: 1) GBM stem cells formed tumors after orthotopic transplantation; AHNSCs showed no sign of tumor formation; 2) GSCs showed a significantly higher growth rate and self-renewal capacity; 3) both the growth rate and telomerase expression were high in GSCs and correlated with malignancy grade (GBM higher than AC II); AHNSCs had low telomerase expression; 4) GSCs invaded normal neurospheres, not vice versa; 5) both AHNSCs and stem cells from AC II and GBM responded to differentiation cues with a dramatic decrease in the proliferation index (Ki-67); 6) GSCs differentiated faster than AHNSCs; 7) upon differentiation, AHNSCs produced normal glia and neurons; GSCs produced morphologically aberrant cells often expressing both glial and neuronal antigens; and 8) differentiation of AHNSCs resulted in 2 typical functional phenotypes: neurons (high electrical membrane resistance, ability to generate action potentials) and glial cells (low membrane resistance, no action potentials). In contrast, GSCs resulted in only 1 functional phenotype: cells with high electrical resistance and active membrane properties capable of generating action potentials.
  
  
  CONCLUSIONS
  AHNSCs and stem cells from AC II and GBM differ with respect to proliferation, tumor-forming capacity, and rate and pattern of differentiation.
authors.affiliation: Vilhelm Magnus Laboratory, Institute for Surgical Research, University of Oslo, Oslo, Norway. mercy.varghese@medisin.uio.no
authors.forename: Mercy
authors.initials: M
authors.lastname: Varghese
authors.forename: Havard
authors.initials: H
authors.lastname: Olstorn
authors.forename: Cecilie
authors.initials: C
authors.lastname: Sandberg
authors.forename: Einar O
authors.initials: EO
authors.lastname: Vik-Mo
authors.forename: Paul
authors.initials: P
authors.lastname: Noordhuis
authors.forename: Monica
authors.initials: M
authors.lastname: Nistér
authors.forename: Jon
authors.initials: J
authors.lastname: Berg-Johnsen
authors.forename: Morten C
authors.initials: MC
authors.lastname: Moe
authors.forename: Iver A
authors.initials: IA
authors.lastname: Langmoen
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D009474:Neurons / Q000473:pathology* / Q000502:physiology*; D013234:Stem Cells / Q000145:classification / Q000473:pathology* / Q000502:physiology*