Noteworthy, in the cancer setting, low efficacy of high-dose IL-2 administration (134) can be explained in part by the unwanted effect of IL-2 on Tregs, which constitutively express the high affinity IL-2 receptor [composed by three subunits: IL-2-Rα (CD25), IL-2Rβ and IL-2Rγ] (135). The gene discussed is IL2RA; the disease is cancer.