IL9 and cancer: Finally, we also tested the anticancer potential of cGAMP-treated TH9 cells against B16F-10 cancer cells in vivo using Trp1 transgenic T cells, which recognize tyrosinase-related protein 1 a specific melanoma tumor antigen.50 We also found in that setting that cGAMP endowed antigen-specific TH9 cells with higher IL-9 production and superior anticancer functions (online supplemental figure S5E, F).