Different combinations of these cytokines, as well as different concentrations will either promote or suppress stem cell activity thus contributing to the pleiotropic effect of IFN-γ and TGF-β1 in AIDs, infections and cancer, and to the pleiotropic effects of α-MSH and IGF-1 on T cell or NK cell function (Table 1). The gene discussed is TGFB1; the disease is cancer.