CCL2, CCL7, CCL9, CCL21, C-X-C motif ligand (CXCL)1, CXCL5, and CXCL12(SDF-1a) have been proven to participate in the development and migration of MDSCs through binding with the corresponding receptors in HCC [22,41,42,43,44]. The gene discussed is CXCL12; the disease is hepatocellular carcinoma.