TLR4 and pancreatic neoplasm: Porphyromonas gingivalis (P. gingivalis), a Gram-negative bacterium implicated in the pathogenesis of human periodontitis, can activate toll-like receptors 4 (TLR4) to enhance the release of proinflammatory cytokines, such as interleukin 1β, interferon γ, and the tumor necrosis factor, to promote pancreatic inflammation and, subsequently, pancreatic cancer [33,34].