TNF and neoplasm: Tumor progression is supported by tumor-promoting cytokines, in which high serum levels of several cytokines, such as vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), transforming growth factor β (TGF-β), and tumor necrosis factor-α (TNF-α), are correlated with advanced stages of lung cancer [4, 5].