IL6 and neoplasm: Researches have demonstrated that MSCs would be recruited into tumor sites, promoting tumor growth, and angiogenesis through differentiating into cancer-associated myofibroblasts and secretion of proangiogenic cytokines (e.g., interleukin (IL)-6, vascular endothelial growth factor (VEGF), and transforming growth factor-β (TGF-β) [21–23].