CCL22 and neoplasm: The expression of the major markers of Treg cells, including FOXP3 (a transcription factor which is mainly related to Treg cell subsets), IL-10 and TGF-β (the signature cytokines of these cells), CCL22 (a chemokine ligand which is involved in Treg cell migration) and CTLA-4 (an inhibitory receptor which is dominantly expressed on Treg cells) in tumor tissue was determined.