CD4 and cancer: In contrast, others have observed the induction of effective antitumor responses following administration of various immunotherapeutic strategies in the absence of cytoablative treatments, and have suggested that such responses are likely due to the balance between effector T cells (i.e., either CD4 or CD8) and TReg cells within treated cancer patients (Alvaro et al., 2005; Quezada et al., 2006; Hunder et al., 2008; Le and Jaffee, 2012; Liu et al., 2012a).