TLR4 and cancer: Fusobacterium nucleatum, a well-studied bacterium in cancer pathogenesis, can bind to TLR4 on cancer cells and activate the nuclear factor-kappaB (NF-κB) signaling cascade, leading to the production of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor -α (TNF-α), which promote a chronic inflammatory state (81).