Radiation can indirectly result in cancer in cells beyond those that are directly irradiated, according to studies in mice by Italian researchers (Mancuso M et al. Proc Natl Acad Sci U S A. 2008;105:12445-12450). The findings suggest that current estimates of cancer risks from radiation exposure may be too low.
Previous studies suggested that irradiated cells cause “bystander” DNA damage and apoptosis (programmed cell death) to unexposed neighboring cells, presumably through some kind of cell-to-cell communication or chemical signals. To test for bystander damage and to see if it could result in cancer, the researchers studied radiation in newborn mice with a mutation in a gene called Patched that makes them prone to develop brain tumors.
Stephenson J. X-ray Collateral Damage?. JAMA. 2008;300(11):1291. doi:10.1001/jama.300.11.1291-b