title: Endothelial cell marker PAL-E reactivity in brain tumor, developing brain, and brain disease.
abstract: BACKGROUND
  The endothelial cell marker PAL-E is not reactive to vessels in the normal brain. The present study concerns the PAL-E reactivity in brain tumors in contrast to normal brain and nonneoplastic brain disease.
  
  
  METHODS
  A total of 122 specimens were examined: brain tumors (n = 94), nonneoplastic brain disease (n = 19), normal brain (n = 8), and fetal brain (n = 1). Standard immunohistochemical procedures using a panel of endothelial cell markers were applied to detect vessels reactive to PAL-E.
  
  
  RESULTS
  PAL-E reactivity to endothelial cells was found in all cases of glioblastoma multiforme, in 75% of the cases of anaplastic astrocytoma, and in 46% of the cases of astrocytoma. Furthermore, PAL-E reactivity was present in diseases with a developmental etiology, such as primitive tumors and congenital vascular malformations. The developing human brain (6-weeks' gestation age) and special sites of the mature brain, sites without blood-brain barrier, showed a strong reactivity, which indicates a relation with the status of blood-brain barrier development.
  
  
  CONCLUSIONS
  PAL-E is the only marker out of a panel of endothelial cell markers that shows no reactivity to endothelial cells in the normal brain with an intact blood-brain barrier. In primary and metastatic brain tumors, PAL-E is reactive to endothelial cells, except for 25% of anaplastic astrocytoma and 54% of astrocytoma. PAL-E reactivity in brain tumors most likely is related to angiogenesis and to blood-tumor barrier properties not present in the normal blood-brain barrier.
authors.affiliation: Department of Neurosurgery, University of Amsterdam, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Leenstra
authors.forename: D
authors.initials: D
authors.lastname: Troost
authors.forename: P K
authors.initials: PK
authors.lastname: Das
authors.forename: N
authors.initials: N
authors.lastname: Claessen
authors.forename: A E
authors.initials: AE
authors.lastname: Becker
authors.forename: D A
authors.initials: DA
authors.lastname: Bosch
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D001254:Astrocytoma / Q000098:blood supply / Q000473:pathology; D015415:Biomarkers; D001812:Blood-Brain Barrier; D001921:Brain / Q000166:cytology / Q000196:embryology*; D001927:Brain Diseases / Q000473:pathology*; D001932:Brain Neoplasms / Q000098:blood supply* / Q000473:pathology; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D002538:Intracranial Arteriovenous Malformations / Q000473:pathology; D009837:Oligodendroglioma / Q000098:blood supply / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers