A number of different immuno-mediators, such as programmed death-ligand 1 (PD-L1), macrophage colony stimulation factor (M-CSF), C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 17 (CCL17), C-C motif chemokine ligand 18 (CCL18) and C-C motif chemokine ligand 22 (CCL22), predominantly released by M2 macrophages, have been linked to increased numbers of both macrophages and Tregs in tumor tissue (15, 17, –, 19). Here, CCL17 is linked to neoplasm.