CXCL12 and cancer: The main radio-mediated mechanism inducing EMT involves the activation of fibroblast in cancer-activated fibroblast (CAFs), which produces an array of cytokines and growth factors after irradiation promoting EMT, primarily represented by TGF-beta and (C-X-C motif) ligand 12 (CXCL12)/stromal derived factor1 (SDF-1) [18,20,21].