IL6 and neoplasm: Consistently, TGFβ1 has also emerged as a key player in the maintenance of self-renewal and stemness [44]; in particular, Tu et al. have demonstrated that the tumor maintains the stemness of MSC through the TGF/Smad3 pathway and that OS cells, via TGFβ1 secretion, enhance the production of pro-tumorigenic cytokines, such as IL-6, in the nearby stroma [34].