title: Detection of p53 mutations in proliferating vascular cells in glioblastoma multiforme.
abstract: OBJECTIVE
  Glioblastoma multiforme (GBM), one of the most aggressive tumors in humans, is highly angiogenic. However, treatment with the angiogenesis inhibitor bevacizumab has not significantly prolonged overall patient survival times. GBM resistance to angiogenesis inhibitors is attributed to multiple interacting mechanisms. Although mesenchymal transition via glioma stem-like cells has attracted attention, it is considered a poor biomarker. There is no simple method for differentiating tumor-derived and reactive vascular cells from normal cells. The authors attempted to detect the mesenchymal transition of tumor cells by means of p53 and isocitrate dehydrogenase 1 (IDH1) immunohistochemistry.
  
  
  METHODS
  Using antibody against p53 and IDH1 R132H, the authors immunohistochemically analyzed GBM tissue from patients who had undergone surgery at the University of Miyazaki Hospital during August 2005-December 2011. They focused on microvascular proliferation with a p53-positive ratio exceeding 50%. They compared TP53 mutations in original tumor tissues and in p53-positive and p53-negative microvascular proliferation cells collected by laser microdissection.
  
  
  RESULTS
  Among 61 enrolled GBM patients, the first screening step (immunostaining) identified 46 GBMs as p53 positive, 3 of which manifested areas of prominent p53-positive microvascular proliferation (>50%). Histologically, areas of p53-positive microvascular proliferation tended to be clustered, and they coexisted with areas of p53-negative microvascular proliferation. Both types of microvascular proliferation cells were clearly separated from original tumor cells by glial fibrillary acidic protein, epidermal growth factor receptor, and low-/high-molecular-weight cytokeratin. DNA sequencing analysis disclosed that p53-positive microvascular proliferation cells exhibited TP53 mutations identical to those observed in the original tumor; p53-negative microvascular proliferation cells contained a normal allele. Although immunostaining indicated that 3 (2 primary and 1 secondary) of the 61 GBMs were positive for IDH1, no tumors contained microvascular proliferation cells positive for IDH1 R132H.
  
  
  CONCLUSIONS
  Some microvascular proliferation clusters in GBM result from mesenchymal transition. The identification of useful markers might reveal this phenomenon as an infrequent event in GBMs.
authors.affiliation: Department of Neurosurgery, Division of Clinical Neuroscience, and.
authors.forename: Takuma
authors.initials: T
authors.lastname: Kawasoe
authors.forename: Hideo
authors.initials: H
authors.lastname: Takeshima
authors.forename: Shinji
authors.initials: S
authors.lastname: Yamashita
authors.forename: Sohei
authors.initials: S
authors.lastname: Mizuguchi
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Fukushima
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Yokogami
authors.forename: Kouji
authors.initials: K
authors.lastname: Yamasaki
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D001808:Blood Vessels / Q000378:metabolism* / Q000473:pathology; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D058750:Epithelial-Mesenchymal Transition; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D012189:Retrospective Studies; D016159:Tumor Suppressor Protein p53 / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D005904:Glial Fibrillary Acidic Protein; D016159:Tumor Suppressor Protein p53; D007633:Keratins; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: GBM = glioblastoma multiforme; IDH1 = isocitrate dehydrogenase 1; PCR = polymerase chain reaction; VEGF = vascular endothelial growth factor; glioblastoma; laser microdissection; mesenchymal transition; microvascular proliferation; oncology; p53