CXCR4 and lung cancer: However, in lung cancer, CXCR4 overexpression facilitates tumor cells to migrate along chemotactic gradients of its ligand CXCL12 (stromal cell-derived factor 1, SDF-1) toward CXCL12-enriched metastatic niches, where tumor adhesion, survival, and immune escape are enhanced (Chandra et al., 2021).