Some research works reported that IL-17A, IL-23, and IL-6 could promote tumor growth and/or impair the function of effector T cells, suggesting that Th17 cells might play a negative role in antitumor immunity [21–23], while others showed that Th17 cells and Th-17 cell-associated cytokines could elevate antitumor immunity in some certain animal models [15, 24, 25]. Here, IL17A is linked to neoplasm.