Divergent functions of TLRs in gastrointestinal (GI) cancer: Overview of their diagnostic, prognostic and therapeutic value

The relationship between the innate immune signal and the start of the adaptive immune response is the central idea of this theory. By controlling the inflammatory and tissue-repair reactions to damage, the Toll-like receptors (TLRs), as a family of PRRs, have attracted increasing attention for its function in protecting the host against infection and preserving tissue homeostasis. Microbial infection, damage, inflammation, and tissue healing have all been linked to the development of malignancies, especially gastrointestinal (GI) cancers. Recently, increased studies on TLR recognition and binding, as well as their ligands, have significantly advanced our knowledge of the various TLR signaling pathways and offered therapy options for GI malignancies. Upon activation by pathogen-associated or damage-associated molecular patterns (DAMPs and PAMPs), TLRs trigger key pathways like NF-κB, MAPK, and IRF. NF-κB activation promotes inflammation, cell survival, and proliferation, often contributing to tumor growth, metastasis, and therapy resistance. MAPK pathways similarly drive uncontrolled cell growth and invasion, while IRF pathways modulate interferon production, yielding both anti-tumor and protumor effects. The resulting chronic inflammatory environment within tumors can foster progression, yet TLR activation can also stimulate beneficial anti-tumor immune responses. However, the functions of TLR expression in GI cancers and their diagnostic and prognostic along with therapeutic value have not yet entirely been elucidated. Understanding how TLR activation contributes to anti-cancer immunity against GI malignancies may hasten immunotherapy developments and increase patient survival.