This study investigates the role of microRNAs (miRNAs) in the promotion of metastasis by binding to Toll-like receptors (TLRs) in immune cells. The authors found that tumor-secreted miR-21 and miR-29a can function as ligands for TLR7 and TLR8, respectively, in immune cells, triggering a TLR-mediated prometastatic inflammatory response. This response leads to tumor growth and metastasis by activating the NF-κB pathway and promoting the secretion of proinflammatory cytokines such as TNF-α and IL-6. The study also demonstrated that this mechanism is important in the tumor microenvironment and may represent a potential target for cancer treatment. The findings highlight the significance of miRNAs as paracrine agonists of TLRs in cancer progression and metastasis.This study investigates the role of microRNAs (miRNAs) in the promotion of metastasis by binding to Toll-like receptors (TLRs) in immune cells. The authors found that tumor-secreted miR-21 and miR-29a can function as ligands for TLR7 and TLR8, respectively, in immune cells, triggering a TLR-mediated prometastatic inflammatory response. This response leads to tumor growth and metastasis by activating the NF-κB pathway and promoting the secretion of proinflammatory cytokines such as TNF-α and IL-6. The study also demonstrated that this mechanism is important in the tumor microenvironment and may represent a potential target for cancer treatment. The findings highlight the significance of miRNAs as paracrine agonists of TLRs in cancer progression and metastasis.