title: Fatty acid binding protein 4 is expressed in distinct endothelial and non-endothelial cell populations in glioblastoma.
abstract: OBJECTIVE
  Glioblastoma (GBM) is the most common and aggressive primary brain tumour in adults. Angiogenesis and vasculogenesis play key roles in progression of GBMs. Fatty acid binding protein 4 (FABP4) is an intracellular chaperone for free fatty acids. FABP4 is detected in microvascular endothelial cells (ECs) in several normal tissues and promotes proliferation of ECs. The goal of this study was to characterize the tissue distribution pattern of FABP4 in GBMs.
  
  
  METHODS
  Immunohistochemistry for FABP4 was performed on paraffin-embedded tumour sections and the intensity and distribution of FABP4 immunoreactivity were analysed. Double immunofluorescence was employed for detailed characterization of FABP4-positive cells.
  
  
  RESULTS
  FABP4 immunoreactivity was absent in normal brain tissue sections. FABP4-positive cells were detected in 33%, 43%, 64% and 89% of Grade I, Grade II, Grade III and Grade IV glial tumours, respectively. Thus, the percentage of FABP4-positive cells in GBMs was significantly higher than lower-grade gliomas. In general, FABP4-expressing cells were distributed in a non-homogenous pattern, as 'hot spots' in glial tumours. FABP4 expression was detected in a subset of vascular ECs as well as some non-ECs.
  
  
  CONCLUSIONS
  FABP4 is expressed in a significantly higher percentage of GBMs in comparison to both normal brain tissues and lower-grade glial tumours. FABP4 is expressed in some tumour ECs as well as non-ECs in glial tumours. As FABP4 promotes proliferation of ECs, detection of FABP4 in GBM-ECs, but not normal brain ECs suggests that FABP4 may play a role in the robust angiogenesis associated with GBMs.
authors.affiliation: Division of Neurosurgery, University of Massachusetts Memorial Medical Center, Worcester, MA 01655, USA. oguz.cataltepe@umassmemorial.org
authors.forename: O
authors.initials: O
authors.lastname: Cataltepe
authors.forename: M C
authors.initials: MC
authors.lastname: Arikan
authors.forename: E
authors.initials: E
authors.lastname: Ghelfi
authors.forename: C
authors.initials: C
authors.lastname: Karaaslan
authors.forename: Y
authors.initials: Y
authors.lastname: Ozsurekci
authors.forename: K
authors.initials: K
authors.lastname: Dresser
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: T W
authors.initials: TW
authors.lastname: Smith
authors.forename: S
authors.initials: S
authors.lastname: Cataltepe
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D042783:Endothelial Cells / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism*; D005260:Female; D005909:Glioblastoma / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000378:metabolism; D055815:Young Adult
chemical_list: C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins