title: Basal oxidative stress ratio of head and neck squamous cell carcinomas correlates with nodal metastatic spread in patients under therapy.
abstract: BACKGROUND
  Head and neck squamous cell carcinoma (HNSCC) is a type of cancer that is strongly associated with oxidative damage and oxidative stress. Tobacco and alcohol - sources of massive quantities of reactive oxygen species (ROS) - have been clearly identified as etiologic factors that contribute to these malignancies. Considering the role of glutathione (GSH) in ROS detoxification, we hypothesized that potential biological markers can be found in addition to the parameters of oxidative stress. In line with previous studies that emphasized the accumulation of GSH in tumor cells, in this study, we have reported a lower ratio of oxidized versus reduced GSH in head and neck tumors.
  
  
  OBJECTIVE
  The aim of the paper was to evaluate the prognostic and clinical significance of the ratio of oxidized versus reduced GSH in patients with head and neck cancers.
  
  
  METHODS
  Thirty-six patients with HNSCC were included in this study. The tumoral redox status was determined by measuring the ratio of oxidized/reduced GSH (GSSG/GSH) by capillary electrophoresis. Statistical analysis was performed to assess the correlation between patient, clinical factors and the redox status.
  
  
  RESULTS
  The results showed a low tumoral ratio of GSSG/GSH and a better locoregional control. Moreover, a significant correlation between the tumoral redox status ratio (GSSG/GSH) and nodal stage (N0 versus N1, N2 and N3) was also observed. A higher tumoral redox status ratio was found to be associated with the presence of lymph node metastasis (N1, N2 and N3).
  
  
  CONCLUSIONS
  A strong correlation was observed between the oxidative status and locoregional control of the tumors. Moreover, a higher basal tumoral redox status ratio was found to be correlated with the presence of lymph node metastasis.
authors.affiliation: Department of Oncology and Experimental Radiotherapy, KU Leuven - University of Leuven, Leuven; Department of Head and Neck Surgery, CHU Charleroi, Montigny.
authors.forename: D
authors.initials: D
authors.lastname: Dequanter
authors.affiliation: Department of Oncology and Experimental Radiotherapy, KU Leuven - University of Leuven, Leuven.
authors.forename: R
authors.initials: R
authors.lastname: Dok
authors.affiliation: Department of Oncology and Experimental Radiotherapy, KU Leuven - University of Leuven, Leuven; Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Nuyts
keywords: glutathione ratio; head and neck cancer; lymph node metastasis; oxidative stress; prognostic factor