A similar effect could be achieved in M2-polarized tumor macrophages that are characterized by aberrant IL-12 production, as PD-1 has been reported to suppress M1 polarization by the inhibition of STAT-1 phosphorylation, and also support M2 polarization by the augmentation of STAT-6 phosphorylation [80]. The gene discussed is PDCD1; the disease is neoplasm.