In tumors, pDCs may play different and sometimes contrasting roles on tumor progression and immune evasion: they can promote tolerance by presenting antigen to CD4+ T cells and inhibiting their activation or inducing Treg, but they also produce large amounts of IFN-α and prime CD4+ and CD8+ T cells, inducing an effective antitumor response [35,36,37,38]. The gene discussed is CD4; the disease is neoplasm.