To investigate the functional role of CXCR4 signaling in the survival activity of NSCLC cells from IR exposure, we treated the cells (A549, A549/GR, and H460) with SDF-1α, a ligand of CXCR4 and AMD3100, a specific antagonist of CXCR4 and performed clonogenic survival assays. Here, CXCR4 is linked to non-small cell lung carcinoma.