Although there is little evidence about the role of IL-34 in the differentiation and action of Tregs in cancer, studies in other systems demonstrated the involvement of IL-34 in human and rat Treg-mediated suppressive functions, as well as the ability of IL-34 to induce in vivo and in vitro CD4+ and CD8+ Tregs through monocytes polarization toward M2-type macrophages [76,77]. The gene discussed is IL34; the disease is cancer.