CCL18 and primary cutaneous T-cell non-Hodgkin lymphoma: Considering other studies suggesting that CCL18 expression from macrophages and dendritic cells in the lesions is related to the severity and progression of CTCL [123,124], the benign Th2 cells within CTCL lesions might serve as pro-tumorigenic T cells and might be associated with the tumor progression of CTCL.