The role of cytokines in radiation oncology.

Cytokine induction following ionizing radiation exposure occurs through transcriptional activation in specific proteins studied to date. This process can be blocked by inhibition of radiation-induced signaling pathways, which may potentially modify certain deleterious effects of radiotherapy, e.g., effects related to production of TNF or TGF-beta. bFGF is another radiation-inducible protein that may participate in repair and protection of irradiated endothelial cells following a complex interaction with cellular receptors. The cytokines such as IL-6, TNF, and IL-1 may be useful to protect hematopoietic cells from radiation, while TNF may enhance the killing of tumor cells. Our understanding of cytokine/radiation interactions is only beginning to be understood, but knowledge of the biology of these interactions may prove clinically useful.