In general, the concentrations of cytokines, including interleukin-1β (IL-1β), IL-6, IL-10, IL-17, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), in the peripheral blood of GC patients are commonly greater than those in healthy subjects, whereas the concentration of macrophage chemotactic protein (MCP)-1 has been found to be lower in several studies (15–19). Here, IL17A is linked to gastric cancer.