We have defined the DNA elements and mechanisms responsible for radiation activation of Egr-1 and jun. Gene therapy is generally not well localized. We proposed that ionizing radiation could be used to activate the transcription of exogenous genes that encodes cytotoxic or radioprotective proteins. When this construct was used in an experimental animal system, we observed an increase in tumor cures without an increase in normal tissue toxicity.
Gene therapy targeted by radiation preferentially radiosensitizes tumor cells.