IL6 and Kaposi's sarcoma: In fact, it is well known that Kaposi sarcoma secrets abundant inflammation cytokines and growth factors including IL-1, IL-6, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), tumor necrosis factor (TNF), interferon-gamma (IFN-γ), and vascular endothelial growth factor (VEGF), as well as KSHV-encoded vIL-6 [38,43–45].