title: Expression of VEGF and collagen XVIII in meningiomas: correlations with histopathological and MRI characteristics.
abstract: BACKGROUND
  The objective of this study was to assess the possibility of predicting histological characteristics of meningiomas on the basis of preoperative MRI and the correlation of the expression of vascular endothelial growth factor (VEGF) and collagen XVIII with histological parameters already established as predictive of the course of these tumors.
  
  
  METHODS
  Expression of VEGF and collagen XVIII as well as other histological characteristics was examined in meningioma tissues from 20 patients. Preoperative MRI, including dynamic imaging of contrast enhancement, was analyzed. Times to maximum enhancement and maximum intensity increase were noted from dynamic imaging. The relative intensity of the tumor in fluid-attenuated inversion recovery (FLAIR), T2-weighted and contrast enhanced T1-weighted images, as well as volumes of tumor and edema, was calculated. The edema-tumor volume ratio was defined as the edema index (EI).
  
  
  RESULTS
  Both VEGF and collagen XVIII were expressed in all meningioma samples. Edema was present in 60 % of cases. The strongest correlation of VEGF expression was to EI. Among histological parameters, microvessel density (MVD) and cellularity correlated moderately with VEGF. Collagen XVIII expression correlated strongly with the maximal intensity increase after contrast agent administration (ρ = 0.71, P = 0.001) as well as with MVD and intensity of the meningioma on FLAIR images.
  
  
  CONCLUSIONS
  Meningiomas with faster and more intense enhancement in dynamic studies, indicative of good tumor blood supply and permeability of vasculature, are associated with high levels of collagen XVIII and VEGF expression. Occurrence of peritumoral edema in meningiomas is strongly correlated with expression of VEGF.
authors.affiliation: Department of Neurosurgery, Institute of Clinical Medicine, University of Oulu, Oulu, P.O. Box 21, 90029 OYS, Finland. niina.salokorpi@ppshp.fi
authors.forename: Niina
authors.initials: N
authors.lastname: Salokorpi
authors.forename: Sanna
authors.initials: S
authors.lastname: Yrjänä
authors.forename: Hannu
authors.initials: H
authors.lastname: Tuominen
authors.forename: Ari
authors.initials: A
authors.lastname: Karttunen
authors.forename: Ritva
authors.initials: R
authors.lastname: Heljasvaara
authors.forename: Taina
authors.initials: T
authors.lastname: Pihlajaniemi
authors.forename: Esa
authors.initials: E
authors.lastname: Heikkinen
authors.forename: John
authors.initials: J
authors.lastname: Koivukangas
mesh_terms: D000328:Adult; D000368:Aged; D001929:Brain Edema / Q000209:etiology / Q000473:pathology*; D043170:Collagen Type XVIII / Q000378:metabolism*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008579:Meningioma / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D008875:Middle Aged; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: D043170:Collagen Type XVIII; D042461:Vascular Endothelial Growth Factor A