In general, Th1 cells can secret Th1 cytokines such as IFN-γ and IL-2 to enhance the antitumor efficacy of CD8+ T cells and NK cells, and Tregs can suppress the antitumor function of T cells [15] and NK cells [16]; while the function of Th2 and Th17 cells in tumor immunity are inconsistently reported to be either anti-tumoral [17,18,19] or pro-tumoral [20,21,22]. This evidence concerns the gene IL2 and neoplasm.