CD4 and neoplasm: TGF-β is well known for its pleiotropic role from initiating to promoting tumor development [14,15,16,17] and it has a negative effect on anti-tumor immunity by suppressing the effector functions of several immune effector cells such as neutrophils, macrophages, natural killer (NK) cells, CD8 cells, and CD4 T cells [16,18,19,20].