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Radiation-induced bystander effects — implications for cancer



The term radiation-induced bystander effects describes a situation where cells that have not been directly exposed to ionizing radiation behave as though they have been exposed: they die or they show chromosomal instability and other abnormalities. The bystander cells might be immediately adjacent or might be some distance away from the exposed cell. Although the nature of the communication system that is involved in producing these responses is not yet known, there is strong evidence for a chemical signalling process that transmits information from the irradiated cell to neighbouring cells. The bystander effect has several important implications for radiation protection, radiotherapy and diagnostic radiology.

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The authors acknowledge support from the following sources in Ireland and Europe: the Science Foundation Ireland; Saint Luke's Institute of Cancer Research; the Cancer Research Advancement Board; and the European Union Radiation Protection Programme.

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Competing interests

The authors declare no competing financial interests.

Correspondence to Carmel Mothersill.

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Further reading

Figure 1: Two views of how radiation effects are perpetuated.
Figure 2: Biological effects of a radiation beam.
Figure 3: Exposure of unirradiated cells to culture medium harvested from irradiated cells causes release of calcium.