Since CAFs enhance tumorigenesis, metastasis, or drug resistance in various cancer cells via secretion of soluble factors23, we detected the mRNA expression of FGF2, TGF-β1, SDF-1, IL-6, IGF-1, CCL18, PDGF-AA, HGF, and TNF-α and confirmed that CAFs highly expressed these cellular factors, especially TGF-β1 and SDF-1 (Fig. S3A). This evidence concerns the gene IL6 and cancer.