Abstract: S100A8 calcium-binding protein is highly conserved, low-molecular-weight acidic protein with important functions. Murine S100A8 is a potent chemoattractant for myeloid cells, and has been associated with a number of acute and chronic inflammatory conditions. Inactivation of the SI00A8 gene is embryonic lethal. Evidence has indicated that ionizing radiation can induce expression of S100A8 gene, so we confirm that S100A8 gene is a new radiation-induced gene.