It appears that gut microbiome modulates anti-cancer adaptive immune response as depletion of gut microbiome in mice bearing pancreatic tumors led to increased IFN-γ secreting CD8 T cells as well as decreased IL-10 and IL-17 secreting T cells (28). Intriguingly, interaction of microbes with CD4+ and CD8+ T cells has been shown to impact the cancer response to immunotherapy and chemotherapy as well. Here, IL17A is linked to cancer.