Identification of a RelB gene expression signature associated with worse outcome of patients with DLBCL treated by R-CHOP. (A) Hierarchical clustering of 202 patients with DLBCL from the GSE87371 cohort with the 140 differentially expressed probe sets identified based on RelB DNA-binding gene expression signature (supplemental Figure 2). Lines and columns of the heatmap correspond to probe sets and patients, respectively. Upregulated genes are coded in green, and downregulated genes are coded in red. COO classification of each case is represented on top of the heatmap. (B) Distribution of RelB activity as defined by GEP among patients with GCB and ABC DLBCL from the GSE 87371 cohort (n = 202). (C) Top: prevalence of RelB activation as defined by using GEP in ABC and GCB DLBCLs (n = 202). Bottom: prevalence of ABC and GCB DLBCLs within the RelB-positive cluster as defined by using GEP (n = 202). (D) RelB signature analysis by the Ingenuity Pathway Analysis software (www.ingenuity.com). (E) Volcano plot depicting the absence of enrichment of ten NF-κB signatures involved in regulatory processes in normal and malignant blood (https://lymphochip.nih.gov/signaturedb/) within the RelB-positive subset (x-axis, log2 enrichment; y-axis, log10 P value <1). P value by Fisher’s exact test. (F) Absence of correlation between Myc (cutoff ≥40%, n = 114 patients), Bcl2 (cutoff ≥50%, n = 95 patients), Myc/Bcl2 coexpression (n = 87 patients), and Bcl6 (cutoff ≥30%, n = 108 patients) as evaluated by immunohistochemistry (IHC) with the RelB gene expression signature. P value by Fisher’s exact test. (G) Kaplan-Meier plot of overall survival of the GSE87371 cohort (R-CHOP–treated patients with ABC and GCB DLBCL, n = 98), according to RelB GEP clusters. P value by log-rank (Mantel-Cox) test. (H) Multivariate analysis of the indicated risk factors for overall survival (GSE87371 cohort, R-CHOP–treated patients, n = 98) using Cox regression. IPI: International Prognostic Index. (I) Patient outcome according to RelB GEP clusters in an independent validation cohort (GSE98588, R-CHOP–treated patients with ABC and GCB DLBCL, n = 58; Chapuy et al,¹⁷ patients with available transcriptomic and clinical data). P value by log-rank (Mantel-Cox) test.