Comparison of bleomycin and radiation in the G2 assay of chromatid breaks

A. D. Adema, J. Cloos, R. H M Verheijen, B. J M Braakhuis*, P. E. Bryant

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose: To compare bleomycin with radiation in the G2 chromatid break assay. Controversy exists in the literature about whether G2 bleomycin chromatid-break sensitivity links with cancer predisposition in the same way as the G2 chromatid radio sensitivity test (the so-called 'G2 assay'). Although bleomycin is referred to as a 'radiomimetic' agent, it differs from radiation in the way the damage is induced. Materials and methods: Epstein-Barr virus-immortalized lymphoblastoid cell lines from two head and neck squamous cell carcinoma patients, two breast cancer patients, two ataxia-telangiectasia patients and two normal control persons were used. Chromosomal damage was determined in cells exposed to 0.3-Gy radiation or 5 mU ml-1 bleomycin. The numbers of chromatid breaks per cell and of aberrations per cell (i.e. breaks and gaps) were determined. Results: A strong positive correlation was found between the two different damage inducers (r=0.99; p<0.001). This correlation was similar for both the breaks per cell and the total aberrations per cell. Inclusion of gaps in the scoring of chromatid breaks was associated with a higher variability of the data, but this did not influence the outcome of this study. Conclusions: Both bleomycin and radiation give the same sensitivity phenotypes as determined by the G2 assay of chromatid breaks. Thus, when no radiation facility is present, bleomycin seems to be a good alternative to radiation for this type of assay.

Original languageEnglish
Pages (from-to)655-661
Number of pages7
JournalInternational Journal of Radiation Biology
Issue number8
Publication statusPublished - 1 Aug 2003

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