title: New Clues in the Malignant Progression of Glioblastoma: Can the Thioredoxin System Play a Role?
abstract: OBJECTIVE
  To evaluate and compare the expression of thioredoxin reductase 1 (TrxR1) in primary and secondary glioblastoma samples.
  
  
  METHODS
  Surgically resected human glioblastoma samples from 40 patients who underwent surgery at our institution were extracted from their histopathological specimens and divided into three groups. Ten histopathologically regular cerebral tissue samples, acquired from the non-neoplastic portion of the specimens, were assigned as the control group. Twenty specimens that included tumoral tissue from each type of glioblastoma (WHO grade IV, primary and secondary) were assigned as the primary and secondary glioblastoma groups. TrxR1 expression was analyzed by using both quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. Isocitrate dehydrogenase 1 (IDH1) mutation was analyzed by immunohistochemistry. Ki-67 proliferative index and apoptosis were also analyzed by immunohistochemistry. The differences between the groups were statistically compared and the correlation between these parameters was analyzed.
  
  
  RESULTS
  The expressions of TrxR1 and Ki-67 values were significantly higher in primary glioblastoma. IDH1 mutation was significantly higher in secondary glioblastoma. TrxR1 expression was found to be highly correlated with the Ki-67 index. The apoptotic index was similar between primary and secondary glioblastoma.
  
  
  CONCLUSIONS
  This study showed a high TrxR1 expression in primary glioblastoma which could indicate a role of the Trx system in promoting the malignant progression by some complex processes.
authors.affiliation: Necmettin Erbakan University, Meram Faculty of Medicine, Department of Neurosurgery, Konya, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Erdi
authors.forename: Bulent
authors.initials: B
authors.lastname: Kaya
authors.forename: Hasan
authors.initials: H
authors.lastname: Esen
authors.forename: Yasar
authors.initials: Y
authors.lastname: Karatas
authors.forename: Siddika
authors.initials: S
authors.lastname: Findik
authors.forename: Fatih
authors.initials: F
authors.lastname: Keskin
authors.forename: Bahadir
authors.initials: B
authors.lastname: Feyzioglu
authors.forename: Erdal
authors.initials: E
authors.lastname: Kalkan
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics*; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000096:biosynthesis / Q000235:genetics; D019394:Ki-67 Antigen / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000502:physiology; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics*; D013879:Thioredoxins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; C513606:PRR13 protein, human; D012097:Repressor Proteins; C491203:TXN protein, human; D013879:Thioredoxins; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human