IL6R and cancer: In contrast to the tumor-promoting effect of IL-6 through the classical IL-6 signaling via membrane IL-6R and glycoprotein 130 (gp130) subunit, in some cancers, IL-6 trans-signaling which is a complex of IL-6 and the soluble IL-6R and membrane gp130 [46], but not IL-6 classic signaling, is mandatory for the development of liver carcinogenesis [46].