IL2 and cancer: During the adoptive T cell immunotherapy, patients’ peripheral blood mononuclear cells (PBMCs) are isolated from surrounding blood and incubated with an anti-CD3 antibody (clone OKT3) and interleukin 2 (IL-2) to promote their proliferation and differentiation into effector T cells, which are then injected back into the patients for cancer treatment [4, 5].