Is there a unifying mechanism for the nontargeted effects of radiation?
DIE, bystander effects and clastogenic factors all indicate that either secreted factors and/or cell-to-cell gap junction communication processes operate to transfer signals from irradiated, or unstable cells, to nonirradiated cells. In addition, these nontargeted effects demonstrate that this factor, or these factors, must be capable of causing genetic damage in the target cell that can ultimately lead to cell death.Wright and colleagues (Kadhim et al., 1992; Lorimore et al., 1998) were the first to demonstrate that induced genomic instability could manifest in the progeny of cells that were not themselves actually irradiated, but were present in the radiation environment at the time of irradiation. They then extended these studies to an in vivo situation and demonstrated that when neutron-irradiated cells were mixed with nonirradiated cells in vitro, then transplanted into recipient mice, genomic instability could be found in the unirradiated cell population (Watson et al., 2000). Th
