By activating the IL-6-mediated STAT3 pathway, CAFs in hepatocellular carcinoma can recruit normal DCs and induce them to transdifferentiate into regulatory DCs (rDCs), disabled DCs that express costimulatory molecules at a low level and hardly present antigens, but secrete inhibitory cytokines such as IDO [199]. Here, IDO1 is linked to hepatocellular carcinoma.