Moreover, when MUC1-ST bound to Siglec-9 expressed by primary macrophages, an M2 tumor associated macrophage phenotype was actively induced, as shown by the inhibition of CD8+ T-cell proliferation and upregulation of the expression of indoleamine 2,3-dioxygenase (IDO), the scavenger receptor CD163, the mannose receptor CD206 and the immunological checkpoint ligand PD-L1 (53). The gene discussed is CD8A; the disease is neoplasm.