title: DNA double-strand break analysis by γ-H2AX foci: a useful method for determining the overreactors to radiation-induced acute reactions among head-and-neck cancer patients.
abstract: OBJECTIVE
  Interindividual variability in normal tissue toxicity during radiation therapy is a limiting factor for successful treatment. Predicting the risk of developing acute reactions before initiation of radiation therapy may have the benefit of opting for altered radiation therapy regimens to achieve minimal adverse effects with improved tumor cure.
  
  
  METHODS
  DNA double-strand break (DSB) induction and its repair kinetics in lymphocytes of head-and-neck cancer patients undergoing chemoradiation therapy was analyzed by counting γ-H2AX foci, neutral comet assay, and a modified version of neutral filter elution assay. Acute normal tissue reactions were assessed by Radiation Therapy Oncology Group criteria.
  
  
  RESULTS
  The correlation between residual DSBs and the severity of acute reactions demonstrated that residual γ-H2AX foci in head-and-neck cancer patients increased with the severity of oral mucositis and skin reaction.
  
  
  CONCLUSIONS
  Our results suggest that γ-H2AX analysis may have predictive implications for identifying the overreactors to mucositis and skin reactions among head-and-neck cancer patients prior to initiation of radiation therapy.
authors: Division of Radiobiology and Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka, India.
authors: Hassan Venkatesh
authors: HV
authors: Goutham
authors: Kamalesh Dattaram
authors: KD
authors: Mumbrekar
authors: Bejadi Manjunath
authors: BM
authors: Vadhiraja
authors: Donald Jerard
authors: DJ
authors: Fernandes
authors: Krishna
authors: K
authors: Sharan
authors: Guruprasad
authors: G
authors: Kanive Parashiva
authors: Satyamoorthy
authors: S
authors: Kapaettu
authors: Satish Rao
authors: SR
authors: Bola Sadashiva
mesh_terms: D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy / Q000009:adverse effects*; D020552:Comet Assay / Q000379:methods; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D006258:Head and Neck Neoplasms / Q000628:therapy*; D006657:Histones / Q000032:analysis*; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000175:diagnosis / Q000235:genetics*; D011836:Radiation Tolerance / Q000235:genetics*; D011855:Radiodermatitis / Q000175:diagnosis / Q000235:genetics; D013280:Stomatitis / Q000175:diagnosis / Q000235:genetics
chemical_list: D005819:Genetic Markers; C468783:H2AX protein, human; D006657:Histones