TLR3 and neoplasm: In spontaneous metastatic mice models, TLR3-deficient mice showed decreased lung metastasis, while tumor-derived exosomal small nuclear RNAs activated TLR3 in lung epithelial cells to induce chemokine secretion (chemokine [C-X-C motif] ligand 1 [CXCL1], CXCL2, CXCL5, and CXCL12), and neutrophil recruitment [49].