The cancer-immunity cycle in motion: The effects of exercise on antitumor immunity.

Physical activity has recently emerged as a promising modulator of antitumor immunity, but the underlying mechanisms are incompletely understood. Here, we review human studies assessing the effects of exercise on the single steps of the cancer-immunity cycle. Interventions were mostly based on acute or continuous high- and moderate-intensity endurance exercise, followed by analyses of immune cell function and serum markers. There is evidence that exercise enhances tumor cell susceptibility to apoptosis and promotes dendritic cell maturation via damage-associated molecular patterns. Catecholamine-mediated NK and CD8T cell mobilization facilitates trafficking to tumors, further supported by vascular and metabolic changes to the tumor microenvironment. Overall, there is evidence from human studies that exercise improves immune cell effector function at different steps of the cancer-immunity cycle, thereby potentiating antitumor responses. These findings support the integration of structured exercise therapy into cancer care, possibly in combination with immunotherapeutic strategies. Further mechanistic and clinical research is warranted to optimize exercise-based interventions.