CCL17 and hepatocellular carcinoma: M2 macrophage markers [29–31] CD206, CD163, CCL17 and CCL18 were investigated to increase while M1 macrophage markers tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and transforming growth factor β (TGF-β) did not change after co-culture with HCC-exo (Fig. 1e,f).