Genes expressed in response to extremely low-dose ionizing radiation in normal human fibroblast

Abstract

Although the public today could be exposed to X-rays as high as 1 cGy due to diagnostic procedures, the biological effects of this low dose range have not been established. We searched through more than 23,000 transcripts in normal human fibroblasts using a novel comprehensive expression analysis method (HiCEP). More than two hundred genes were upregulated transiently by 1 cGy of X-rays during the one hour period after irradiation. Within ten genes with increased expression of more than 2 fold in the exposed cells, three encoded proteins which share a known function associated with tumor progression. Our results indicate that human cells respond to doses of radiation as low as 1 cGy, and mechanisms alternative to those involved in moderate/high dose studies have to be considered in understanding the biological effects of diagnostic level radiation.