Role of Toll-like receptors in microbiota-associated gastrointestinal cancer metastasis

Toll-like receptors (TLRs) serve as specific pattern recognition molecules that bind to microbial components to activate innate immunity and instruct and modulate adaptive immunity in the face of immunological danger. Accumulating evidence supports that TLR signaling pathway responses to luminal microbes participate in the development of gastrointestinal malignancies. This review summarizes current knowledge on the roles of TLR in microbiota-associated gastrointestinal cancer metastasis, focusing on TLR recognition of microbiota ligands, initiating inflammation, and promoting tumorigenesis, as well as the therapeutic strategies to target TLR. Studying the link between TLR signaling and gastrointestinal malignancies offers the possibility to identify novel ways to both prevent and treat gastrointestinal cancer.