IL4 and neoplasm: However, upon stimulation with IPP, Vγ9Vδ2 T cells can also be polarized into Th2-like cells, which are characterized by increased secretion of interleukin (IL)-4 upon stimulation with IL-4 and anti-IL-12 antibodies (54) and Treg-like γδ-T cells with regulatory/immunosuppressive functions in the presence of IL-15 and transforming growth factor-β (55), displaying the functions for promoting tumor development through direct or indirect strategies.