IL6 and neoplasm: Paracrine interaction, leading to CAF differentiation, is affected by tumor cell-derived growth factors and cytokines such as transforming growth factor β (TGF-β), epidermal growth factor (EGF), platelet-derived growth factor α/β (PDGFα/β), basic fibroblast growth factor (bFGF, also known as FGF2), interleukin 6 (IL-6), and interleukin 1β (IL-1β) (7).