Toll-Like Receptors in the Immunotherapy Era: Dual-Edged Swords of Tumor Immunity and Clinical Translation.

Toll-like receptors (TLRs), which are critical components of innate immunity, play a significant role in immune responses and deepen our understanding of TLRs. TLRs are a group of transmembrane proteins with similar structures distributed on the cell membrane and endosomes. They trigger downstream acute or chronic inflammatory responses by recognizing different types of pathogen-associated molecular patterns and damage-associated molecular patterns. TLRs play pivotal regulatory roles in various tumor types. Over the past few decades, research on TLRs has become increasingly popular, and these molecules can not only directly recognize tumor components as potential targets to activate antitumor immune responses but also act as accomplices to tumor progression and even as driver genes in certain tumor types. Despite their importance, the mechanisms underlying their dual functions remain poorly understood, creating a gap in current research. Here, we summarize the latest advancements in TLR signaling pathways and their application in tumor therapy in recent years, and highlight the development prospects and potential of TLRs in tumor therapy. Moreover, this review underscores the critical regulatory roles of TLRs across various tumor types and explores their prospects in oncology, offering valuable insights for developing targeted therapies and improving cancer outcomes.