title: G2 chromosomal radiosensitivity in fibroblasts of ataxia-telangiectasia heterozygotes and a Li-Fraumeni syndrome patient with radioresistant cells.
abstract: OBJECTIVE
  To investigate whether the good discrimination we previously observed between ataxia-telangiectasia (A-T) heterozygotes and normal donors for induction of chromosome aberrations by X-rays in G2 lymphocytes is also seen in G2 fibroblasts. Also to investigate the G2 radiosensitivity of a patient with the cancer-prone Li-Fraumeni syndrome (LFS) whose fibroblasts are resistant to the lethal effects of radiation.
  
  
  METHODS
  Fibroblasts were exposed to 0.5 Gy X-rays and harvested for metaphase analysis 90 min later.
  
  
  RESULTS
  Four A-T heterozygote cell strains were all more sensitive than seven normal controls. The LFS strain with a germline TP53 mutation was twice as sensitive as the mean control value.
  
  
  CONCLUSIONS
  Although chromosomal, radiosensitivity is seen in A-T heterozygotes and LFS cells, the former are radiosensitive and the latter radioresistant to cell killing. Repair defects may predominate in A-T heterozygotes, inadequate genome surveillance in LFS cells.
authors.affiliation: CRC Department of Cancer Genetics, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Withington, Manchester, UK.
authors.forename: E L
authors.initials: EL
authors.lastname: Mitchell
authors.forename: D
authors.initials: D
authors.lastname: Scott
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics / Q000473:pathology*; D002869:Chromosome Aberrations; D002877:Chromosomes, Human / Q000528:radiation effects*; D005347:Fibroblasts / Q000528:radiation effects / Q000648:ultrastructure*; D016195:G2 Phase / Q000528:radiation effects*; D006579:Heterozygote; D006801:Humans; D016864:Li-Fraumeni Syndrome / Q000235:genetics / Q000473:pathology*; D011836:Radiation Tolerance / Q000502:physiology*