CXCL12 and neoplasm: Some cytokines, chemokines or growth factors such as tumor growth factor-β (TGF-β), the chemokine C-C motif ligand 2 (CCL2), colony-stimulating factor 1 (CSF-1), C-X-C motif chemokine ligand 12 (CXCL12), or insulin-like growth factor 1 (IRF1) are induced by RT in the tumor environment.