Genetic classification helps to disclose molecular heterogeneity and therapeutic implications in diffuse large B-cell lymphoma (DLBCL). Using whole exome/genome sequencing, RNA-sequencing, and fluorescence in situ hybridization in 337 newly diagnosed DLBCL patients, we established a simplified 38-gene algorithm (termed ‘LymphPlex’) based on the information on mutations of 35 genes and rearrangements of three genes (BCL2, BCL6, and MYC), identifying seven distinct genetic subtypes: TP53Mut (TP53 mutations), MCD-like (MYD88, CD79B, PIM1, MPEG1, BTG1, TBL1XR1, PRDM1, IRF4 mutations), BN2-like (BCL6 fusion, NOTCH2, CD70, DTX1, BTG2, TNFAIP3, CCND3 mutations), N1-like (NOTCH1 mutations), EZB-like (BCL2 fusion, EZH2, TNFRSF14, KMT2D, B2M, FAS, CREBBP, ARID1A, EP300, CIITA, STAT6, GNA13 mutations, with or without MYC rearrangement), and ST2-like (SGK1, TET2, SOCS1, DDX3X, ZFP36L1, DUSP2, STAT3, IRF8 mutations). Extended validation of 1001 DLBCL patients revealed clinical relevance and biological signature of each genetic subtype. TP53Mut subtype showed poor prognosis, characterized by p53 signaling dysregulation, immune deficiency, and PI3K activation. MCD-like subtype was associated with poor prognosis, activated B-cell (ABC) origin, BCL2/MYC double-expression, and NF-κB activation. BN2-like subtype showed favorable outcome within ABC-DLBCL and featured with NF-κB activation. N1-like and EZB-like subtypes were predominated by ABC-DLBCL and germinal center B-cell (GCB)-DLBCL, respectively. EZB-like-MYC+ subtype was characterized by an immunosuppressive tumor microenvironment, while EZB-like-MYC- subtype by NOTCH activation. ST2-like subtype showed favorable outcome within GCB-DLBCL and featured with stromal-1 modulation. Genetic subtype-guided targeted agents achieved encouraging clinical response when combined with immunochemotherapy. Collectively, LymphPlex provided high efficacy and feasibility, representing a step forward to the mechanism-based targeted therapy in DLBCL.

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The incidence of diffuse large B-cell lymphoma (DLBCL) increases by age and older DLBCL are commonly related to poor prognosis. However, the clinical and biological features of older DLBCL patients remain to be determined. A total of 2,445 patients with newly diagnosed DLBCL were enrolled for clinical data analysis according to age at diagnosis, with tumor samples of 1,150 patients assessed by DNA sequencing and 385 patients by RNA sequencing. Older DLBCL presented advanced disease stage, elevated serum lactate dehydrogenase, poor performance status, multiple extranodal involvement, high percentage of double expressor subtype, and adverse clinical outcome. According to molecular features, age was positively correlated with the oncogenic mutations of PIM1, MYD88, BTG2, CD79B, TET2, BTG1, CREBBP, TBL1XR1, and with the MYD88-like genetic subtype. These oncogenic mutations were involved in B-cell receptor/NF-κB signaling, B-cell differentiation, and histone acetylation based on biological functions. Older DLBCL also manifested reduction in CD4+ naïve T and CD8+ naïve T cells, and also increased recruitment of exhausted T cells and macrophages, leading to immunosuppressive tumor microenvironment. Our work thus contributes to the understanding of aging-related oncogenic mutations and tumor microenvironment alterations in lymphoma progression, and may provide new insights to mechanism-based targeted therapy in DLBCL.

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