IL6 and neoplasm: Increased circulating levels of specific adipose tissue-derived cytokines have been reported to promote tumor cell growth (tumor necrosis factor-a [TNF-a], interleukin [IL]-6), enhance metastasis (TNF-a, IL-6, transforming growth factor [TGF]-b), increase angiogenesis (TNF-a, IL-17, TGF-b) and impair the function of macrophages and NK cells [24,33].