Lipopolysaccharide (LPS) present on the outer membrane of gram-negative bacteria including Salmonella, is a potent stimulator of TNF expression by macrophages; while flagellin, a protein subunit present in the bacterial flagellum improves the CD8+ T-cell-dependent antitumour response through activation of toll-like receptor 5 (TLR5) by suppressing tumour cell proliferation and induction and activation of NK cells. This evidence concerns the gene TNF and neoplasm.