We finally obtained ten key genes that are closely associated with the prognosis of DLBCL patients, including CXCL9, TIFAB, C3, VCVAM1, ZBE, D2, TIMD4, KLHL14, TNFRSF9, FCRL3 and PLEKHG1. The gene discussed is C3; the disease is diffuse large B-cell lymphoma.