title: Lack of a correlation between γH2AX foci kinetics in lymphocytes and the severity of acute normal tissue reactions during IMRT treatment for head and neck cancer.
abstract: OBJECTIVE
  To investigate the phosphorylated histone H2A isoform X (γH2AX) foci kinetics as an indicator for the development of acute normal tissue complications during Intensity-Modulated Radiotherapy (IMRT) for head and neck cancer (HNC) patients.
  
  
  METHODS
  Microscopic scoring of the γH2AX foci was used to evaluate the DNA-double-strand-break repair capacity in from Ataxia-Telangiectasia (A-T) patients derived lymphoblastoid cell lines (LCL) and T-lymphocytes isolated from 31 IMRT treated HNC patients. Cells were irradiated in vitro with 0.5 Gy given at high-dose-rate (HDR) and examined at several times up to 24 h after irradiation. The patients were subdivided in three groups showing mild, moderate and severe acute normal tissue complications based on their Common Toxicity Criteria grades for dysphagia, mucositis and dermatitis during the radiotherapy course.
  
  
  RESULTS
  For the ATM (Ataxia-Telangiectasia-Mutated) defective LCL, a lower number of radiation-induced foci and a somewhat less efficient repair capacity was observed. No correlation was found between the γH2AX foci kinetics pattern and the risk for acute normal tissue complications among the three patient subgroups.
  
  
  CONCLUSIONS
  Scoring of γH2AX foci after in vitro irradiation of isolated T-lymphocytes of HNC patients cannot be applied to predict for the development of acute normal tissue complications.
authors.affiliation: Department of Basic Medical Sciences, Ghent University, Gent, Belgium. joke.werbrouck@ugent.be
authors.forename: Joke
authors.initials: J
authors.lastname: Werbrouck
authors.forename: Fréderic
authors.initials: F
authors.lastname: Duprez
authors.forename: Wilfried
authors.initials: W
authors.lastname: De Neve
authors.forename: Hubert
authors.initials: H
authors.lastname: Thierens
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D002460:Cell Line; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects; D006258:Head and Neck Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy*; D006657:Histones / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D011836:Radiation Tolerance; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects
chemical_list: C468783:H2AX protein, human; D006657:Histones