In patients with esophageal cancer undergoing treatment, we found that the incidence of radiation-induced toxicities, including radiation esophagitis, radiation pneumonitis, leukopenia, thrombocytopenia, and anemia, in the high-SOD group was significantly lower than that in the low-SOD group, indicating that high SOD activity could lead to improved radiotherapy tolerability compared to the low SOD activity. The gene discussed is SOD1; the disease is esophageal cancer.