CD4 and neoplasm: Treg cells from CD4+ CD25– T cells are induced and increase in number in cancer patients (Torgerson and Ochs, 2002), and in experimental tumor models, the application of monoclonal antibodies (mAbs) to deplete these cells is associated with increased immunity against tumor antigens and improved survival rates (Morse et al., 2002; Nishikawa and Sakaguchi, 2010).