CD4 and neoplasm: Immuno-suppressive cytokines (IL-10, TGF-β) secreted by tumor cells, suppressor macrophages, and T regulatory (CD4+ Treg) cells that in association with additional mediators or cell:cell interactions inhibit the pro-inflammatory functions of dendritic cells, provoke chronic inflammation associated with tumorigenesis, and prevent a specific adaptive immune response required in tumor eradication [12,32].