Scientists have uncovered how the gut microbiota help the immune system fight melanoma, explaining why patients with a fiber-rich diet and balanced gut bacteria tend to respond better to cancer immunotherapies. The study shows that molecules produced by gut bacteria upon digestion of dietary fiber can improve the function of cancer-fighting immune cells. The research team found that these digestive by-products influence melanoma progression by naturally boosting killer T cell function in pre-clinical cancer models. "Melanoma patients undergoing immunotherapy can benefit from a fiber-rich diet and previous studies suggested that what we eat affects the immune system. However, how that...