CD4 and neoplasm: CD4+ regulatory T cells have been identified that are specific for a variety of tumor antigens, including antigens commonly targeted by vaccination such as gp100, NY-ESO-1, HER2/neu, and CEA (Wang et al., 2004, 2005; van der Burg et al., 2007; Vence et al., 2007; Lehe et al., 2008; Welters et al., 2008; Bonertz et al., 2009; Mougiakakos et al., 2010).