G2 chromosomal radiosensitivity in fibroblasts of ataxia-telangiectasia heterozygotes and a Li-Fraumeni syndrome patient with radioresistant cells.
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.
Mitchell
E L
EL
CRC Department of Cancer Genetics, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Withington, Manchester, UK.
Scott
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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*