[en] To identify genes that are associated with radiosensitivity in different p53 gene status, we used a cDNA microarray containing 161 genes related to apoptosis. Two kind of cells of wild-type p53 cells (SAS/neo) and mutation-type p53 cells (SAS/mp53) were utilized to clarify the expression of genes which induce apoptosis at different times after 6 Gy irradiation. The gene expression of casper was over 10 fold high in gene expression at 36 hr in SAS/neo cells as compared as unirradiated cells, whereas the gene expression of caspase disappeared at 2 hr in SAS/mp53 cells. These results suggest that the casper gene might play an important role for radiosensitivity. (author)