IL6 and cancer: The recent characterization of IL-6 trans-signaling [24] suggests that tumor microenvironments may provide soluble IL-6Rα as well as IL-6 to maximally induce cancer cell aggressiveness through highly augmented IL-6 signaling, which is implicated in tumor cell survival, cancer stem cell characteristics and EMT phenotypes important for successful distant metastasis of cancer cells [5,6].