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. This evidence concerns the gene CXCL9 and diffuse large B-cell lymphoma.