Eight weeks of wheel running 5 days/week with gradually increasing duration (10 to 26 min/day) and gradually increasing intensity (6 to 33 m/min, Table 1) in mice injected with 4T1 carcinoma cells revealed a higher intratumoral CD8+/FoxP3+ ratio, longer overall survival, and reduced tumor size compared with control mice. The gene discussed is CD8A; the disease is neoplasm.