Radiation-induced chromosomal instability in BALB/c and C57BL/6 mice: The difference is as clear as black and white

B. Ponnaiya, M. N. Cornforth, R. L. Ullrich

Research output: Contribution to journalArticlepeer-review

181 Scopus citations


Genomic instability has been proposed to be the earliest step in radiation-induced tumorigenesis. It follows from this hypothesis that individuals highly susceptible to induction of tumors by radiation should exhibit enhanced radiation-induced instability. BALB/c white mice are considerably more sensitive to radiation-induced mammary cancer than C57BL/6 black mice. In this study, primary mammary epithelial cell cultures from these two strains were examined for the 'delayed' appearance of chromosomal aberrations after exposure to 137Cs γ radiation, as a measure of radiation-induced genomic instability. As expected, actively dividing cultures from both strains showed a rapid decline of initial asymmetrical aberrations with time postirradiation. However, after 16 population doublings, cells from BALB/c mice exhibited a marked increase in the frequency of chromatid-type breaks and gaps which remained elevated throughout the time course of the experiment (28 doublings). No such effect was observed for the cells of C57BL/6 mice; after the rapid clearance of initial aberrations, the frequency of chromatid-type aberrations in the irradiated population remained at or near those of nonirradiated controls. These results demonstrate a correlation between the latent expression of chromosomal damage in vitro and susceptibility for mammary tumors, and provide further support for the central role of radiation-induced instability in the process of tumorigenesis.

Original languageEnglish (US)
Pages (from-to)121-125
Number of pages5
JournalRadiation research
Issue number2
StatePublished - 1997

ASJC Scopus subject areas

  • Biophysics
  • Radiation
  • Radiology Nuclear Medicine and imaging


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