Keywords: DLBCL; diffuse large B-cell lymphoma; R-CHOP; rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone; NHL; non-Hodgkin lymphoma; GEP; gene expression profiling; COO; cell-of-origin; GCB; germinal center B-cell; ABC; activated B-cell; PMBL;