TLR3 and neoplasm: In a recent study, toll-like receptor 3 (TLR3) on lung epithelial cells is responsible for triggering neutrophil recruitment and lung pre-metastatic niches by sensing tumor exosomal RNA to induce secretion of chemokines (CXCL1, CXCL2, CXCL5, and CXCL12) [28].