CXCL12 and hepatocellular carcinoma: In the human hepatocellular carcinoma, APS can relieve the immune-suppressive effects of Treg cells by restoring the balance of cytokines in the TME, suppressing the expression of FOXp3 mRNA or inhibiting Treg cell migration by blocking SDF-1 and its receptor via the CXCR4/CXCL12 pathway [105].