CCL20 and neoplasm: In addition, the chemokine receptor CCR6 [which binds to the chemokine CC ligand 20 (CCL20) that is present in many malignant pleural effusions of lung cancer patients] is highly expressed on Th17 cells thus further facilitating their recruitment to sites of tumor growth and inflammation (Acosta-Rodriguez et al., 2007; Annunziato et al., 2007, 2012).