CCL2 and hepatocellular carcinoma: Alterations in the expression of enzymes, including receptor-interacting protein kinase 3, apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3B, and cell cycle-related kinase, activate multiple signal transduction pathways in HCC cells, leading to the generation of IL-6, chemokines (CXCL1, CCL2, and CCL15), and growth factors, inducing the recruitment and proliferation of MDSCs [199–202].