In this study, we determined that 12.5–50 μM of RSV treatment could induce the upregulation of Rad9, which is triggered by DDR activation and ROS production, and can lead to the upregulation of p21with concomitant downregulation of Slug to suppressed the tumorigenicities of breast and lung cancer cell lines. This evidence concerns the gene SNAI2 and lung carcinoma.