IL6 and neoplasm: Tumor-derived stimuli that can transform fibroblasts into CAFs are factors secreted by the tumor and the immune infiltrate, such as transforming growth factor β (TGF-β) family ligands, lysophosphatidic acid (LPA), fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), interleukin-1 (IL-1), IL-6 and granulin [71,72,73].