Interleukin‐6/STAT3 signaling as a promising target to improve the efficacy of cancer immunotherapy

monocyte-derived DC. Moreover, we confirmed that cyclooxygenase 2, lysosome protease and arginase activities were involved in the IL-6-mediated downregulation of the surface expression levels of HLA class II on human DC. These findings suggest that IL-6-mediated STAT3 activation in the tumor microenvironment inhibits functional maturation of DC to activate effector T cells, blocking introduction of antitumor immunity in cancers. Therefore, we propose in this review that blockade of the IL-6/STAT3 signaling pathway and target molecules in DC may be a promising strategy to improve the efficacy of immunotherapies for cancer patients.