CXCL2 and neoplasm: Activation of lung epithelial TLR3 by RNAs in tumor-derived exosomes via NF-kB and MAPK pathways increased the production of chemokines such as CXCL1, CXCL2, CXCL5, and CXCL12, leading to the recruitment and accumulation of neutrophils for PMN formation (58).