Jennifer McQuade, MD

Immunotherapy is a type of cancer treatment that helps the body’s immune system fight cancer. It has changed how we treat many cancers. But not all patients benefit from it. So, we need new ways to make this treatment work better. One area of interest is the gut microbiome. This is the group of trillions of bacteria that live in our gut. These bacteria can affect how the immune system works and how well immunotherapy works. Our research, and that of others, has shown that people who respond to immunotherapy have different gut bacteria than those who do not. Diet plays a big role in shaping the gut microbiome, as the bacteria in our gut eat what we eat. We have shown that diet is linked to how well people respond to immunotherapy. In mice, changing the diet changed both the gut bacteria and the response to treatment. Now, we are testing if diet changes can help patients who are starting immunotherapy. We want to see if we can improve their gut bacteria and boost their immune response through their diet. If this works, it could be a simple and low-cost way to help more people benefit from immunotherapy. We also found that a plant-based, high-fiber diet lowers certain bile acids in the body; these acids may weaken the patient’s immune response. In this study, we will test if these bile acids can be used as a marker of the extent to which the diet and treatment are working.