What’s more, Zhang and colleagues reported that OS cell-derived exosomes convert normal fibroblasts to cancer-associated fibroblasts (CAFs) by secreting pro-inflammatory cytokines, including interleukin-6 (IL-6) and interleukin-8 (IL-8), and activated CAFs promote OS metastasis by regulating the TGF-β/COL6A1 signaling pathway [40]. Here, IL6 is linked to cancer.