IL6 and cancer: After treatment with CM collected from fibroblasts pre-treated by exosomes derived from high-metastatic cancer cell-derived exosomes, tumor cells showed increased spheroid formation ability, motility, and resistance ability to sorafenib (Supplementary Fig. 5b–d), and these phenomena were partially reversed by blocking IL-6 or IL-8 with neutralizing antibody (Supplementary Fig. 5e–g).