STAT3 and hepatocellular carcinoma: In DCs, IL-6 secreted by liver tumor cells and hepatic carcinoma-associated fibroblasts (hCAFs) could bind to the corresponding IL-6R on DCs, activate janus kinase (JAK), and then start the downstream phosphorylation cascade of STAT3 signaling pathway to inhibit T cells proliferation and increase Tregs production (104) (Figure 2).