In the HCC tumor microenvironment, chemokines and cytokines, such as stromal cell-derived factor 1 alpha (SDF-1α, CXCL12a) and IL-6, can induce MDSC infiltration and activation (IL-6/STAT3-mediated) to suppress the antitumor immune response and promote tumor progression [69]. Here, IL6 is linked to hepatocellular carcinoma.