title: Expression and Prognostic Value of Oct-4 in Astrocytic Brain Tumors.
abstract: BACKGROUND
  Glioblastomas are the most frequent type of malignant primary brain tumor with a median overall survival less than 15 months. Therapy resistance of glioblastomas has been attributed to the presence of tumor initiating stem-like cells (TSCs). TSC-related markers have therefore been suggested to have promising potentials as prognostic markers in gliomas.
  
  
  RESULTS
  The aim of the present study was to investigate the expression and prognostic impact of the TSC-related marker Oct-4 in astrocytic brain tumors of increasing grade. In total 114 grade II, III and IV astrocytic brain tumors were immunohistochemically stained for Oct-4, and the fraction and intensity of Oct-4 positive cells were determined by morphometric analysis of full tumor sections. Oct-4 was expressed in all tumors, and the Oct-4 positive cell fraction increased with tumor grade (p = 0.045). There was no association between survival and Oct-4 positive cell fraction, neither when combining all tumor grades nor in analysis of individual grades. Oct-4 intensity was not associated with grade, but taking IDH1 status into account we found a tendency for high Oct-4 intensity to be associated with poor prognosis in anaplastic astrocytomas. Double immunofluorescence stainings showed co-localization in the perivascular niches of Oct-4 and two other TSC markers CD133 and nestin in glioblastomas. In some areas Oct-4 was expressed independently of CD133 and nestin.
  
  
  CONCLUSIONS
  In conclusion, high Oct-4 fraction was associated with tumor malignancy, but seemed to be without independent prognostic influence in glioblastomas. Identification of a potential prognostic value in anaplastic astrocytomas requires additional studies using larger patient cohorts.
authors.affiliation: Department of Pathology, Odense University Hospital, Odense C, Denmark.
authors.forename: Jeanette
authors.identifier: http://orcid.org/0000-0002-5093-5985
authors.initials: J
authors.lastname: Krogh Petersen
authors.affiliation: Department of Pathology, Odense University Hospital, Odense C, Denmark.|Department of Clinical Research, University of Southern Denmark, Odense C, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Jensen
authors.affiliation: Department of Pathology, Odense University Hospital, Odense C, Denmark.|Department of Clinical Research, University of Southern Denmark, Odense C, Denmark.
authors.forename: Mia
authors.initials: M
authors.lastname: Dahl Sørensen
authors.affiliation: Department of Pathology, Odense University Hospital, Odense C, Denmark.|Department of Clinical Research, University of Southern Denmark, Odense C, Denmark.
authors.forename: Bjarne
authors.initials: B
authors.lastname: Winther Kristensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D050814:Octamer Transcription Factor-3 / Q000378:metabolism*; D011379:Prognosis; D015996:Survival Rate; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human