After hyper-fractionated radiotherapy, the level of serum soluble CD28 (sCD28) decreased, and since previous studies have shown a negative correlation between serum sCD28 and the level of CD28 on the T-cell membrane surface (22), we speculate that hyper-fractionated radiotherapy can increase the level of CD28 on the surface of T cells in DLBCL patients, thereby enhancing the anti-tumor effect. The gene discussed is CD28; the disease is diffuse large B-cell lymphoma.