IL4 and cancer: Based on the fact that DC maturation is a necessary first step for these cells to uptake antigen, migrate, and stimulate T cells [32], one option is that ex vivo generated DCs from advanced cancer patients might not have sufficient capacity for inducing tumor antigen-specific immune responses due to the inefficiency of typical DC differentiation cultures (i.e., with GM-CSF and IL-4 or other stimulating cocktails).