CD4 and neoplasm: Our results showed that the frequencies of IFN-γ+CD4+ (26.2 ± 4.2%) and IL-21+CD4+ T cells (8.03 ± 4.37%) in tumor tissue were higher than those of IL-4+CD4+ (0.8 ± 0.5%, P< 0.01 and P< 0.01, respectively), IL-9+CD4+ (1.2 ± 0.7%, P< 0.01 and P< 0.01, respectively), and IL-17+CD4+ T cells (3.2 ± 2.6%, P< 0.01 and P< 0.01, respectively), which indicated that IFN-γ and IL-21 may be the dominant secreted cytokines of tumor-infiltrating Th cells (Figures 1A, B, Supplementary Figure 1).