title: [Genetic predisposition and radiation sensitivity of normal tissue].
abstract: BACKGROUND
  After radiotherapy there are always some patients who develop strong acute and late reactions in normal tissues. In these patients frequently a genetic predisposition is observed. There are found DNA-repair deficiencies and changes in the regulation of the cell cycle which are responsible for the increased radiosensitivity with enhanced cell killing.
  
  
  METHODS
  The micronucleus test and the comet assay appear to be appropriate tests in order to measure this increased radiosensitivity. Both tests are characterized by being relatively quick and simple and can be performed with small cell numbers. It is possible to study blood lymphocytes and fibroblasts with these tests.
  
  
  RESULTS
  Both tests can predict the radiosensitivity of normal tissues especially if they are applied in combination.
  
  
  CONCLUSIONS
  Epidemiological studies with patients after radiotherapy show evidence that the increased radiosensitivity also causes an enhanced induction of secondary tumors by ionizing radiation. This is supported by corresponding animal models.
authors.affiliation: Institut für Medizinische Strahlenbiologie, Universitätsklinikum Essen.
authors.forename: C
authors.initials: C
authors.lastname: Streffer
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics / Q000532:radiotherapy; D006801:Humans; D016864:Li-Fraumeni Syndrome / Q000235:genetics / Q000532:radiotherapy; D015162:Micronucleus Tests; D009362:Neoplasm Metastasis / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics* / Q000532:radiotherapy; D009378:Neoplasms, Multiple Primary / Q000235:genetics / Q000532:radiotherapy; D017253:Neurofibromatoses / Q000235:genetics / Q000532:radiotherapy; D011832:Radiation Injuries / Q000175:diagnosis / Q000628:therapy; D011836:Radiation Tolerance; D011878:Radiotherapy / Q000009:adverse effects; D012175:Retinoblastoma / Q000235:genetics / Q000532:radiotherapy