Mechanistically, transcription factor forkhead box protein O1 (+) tumor cells secrete chemokine ligand 20 (CCL20) to promote M2 macrophage recruitment, and this effect can be inhibited by anti-CCL20 antibodies.[61] NADPH oxidase 4 is also abundantly expressed in non-small cell lung cancer (NSCLC), and it can recruit M2 TAMs by activating the ROS/PI3K signaling pathway to produce various cytokines and promote the growth of NSCLC cells.[62]. Here, NOX4 is linked to non-small cell lung carcinoma.