CCL22 and neoplasm: The expression of CCR4 was more pronounced than expression of CCR3, CCR5, and CCR8 in circulating Treg cells (Fig 4A);with a significantly lower number of Treg cells in normal controls (50.52%) expressing this chemokine receptor than Treg cells in NIP (62.02%)or SSCC (63.82%) (Fig 4A).The expression of ligand CCL22 was increased with invasive progression from normal to NIP to SSCC in local tumor (Fig 4B).