The differentiation of CAFs is crucial for cancer initiation and progression, and it is regulated by signaling pathways induced by tumor cell-derived TGF-β, EGF, PDGFα, PDGFβ, basic fibroblast growth factor (bFGF, also known as FGF2), interleukin 6 (IL-6), and interleukin 1β (IL-1β) [264]. This evidence concerns the gene IL6 and cancer.