Obesity as an immune-modifying factor in cancer immunotherapy.

Immunotherapy has achieved breakthrough status in many advanced stage malignancies and is rapidly becoming the fourth arm of cancer treatment. Although cancer immunotherapy has generated significant excitement because of the potential for complete and sometimes durable responses, there is also the potential for severe and occasionally life-threatening toxicities, including cytokine release syndrome and severe autoimmunity. A large body of work also points to a "metainflammatory" state in obesity associated with impairment of immune responses. Because immune checkpoint blockade (and other cancer immunotherapies) have altered the landscape of immunotherapy in cancer, it is important to understand how immune responses are shaped by obesity and how obesity may modify both immunotherapy responses and potential toxicities.