Targeted sequencing in DLBCL, molecular subtypes, and outcomes: a Haematological Malignancy Research Network report

Toll-like receptor 9 (TLR9) expression correlates with cell of origin and predicts clinical outcome in diffuse large B-cell lymphoma

BACKGROUND

Biological insights beyond the cell-of-origin (COO) classification can support clinical management in diffuse large B-cell lymphoma (DLBCL). We investigated if Toll-like receptor 9 (TLR9) expression could serve as a prognostic marker in DLBCL.

METHOD

TLR9 gene expression was analysed in four publicly available cohorts (n = 2474), and protein expression was investigated in germinal centre B-cell (GCB) and activated B-cell (ABC) DLBCL cell lines. Next, TLR9 protein expression was analysed in 120 diagnostic samples from R-CHOP-treated patients with relapsed/refractory disease (poor outcome, n = 50) or in complete remission (good outcome, n = 70). Associations were evaluated using logistic regression, estimating odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

TLR9 gene expression was higher in ABC DLBCL compared to GCB DLBCL in external cohorts, and similar results were obtained for protein expression in cell lines. In patient samples, high TLR9 protein expression correlated with non-GCB type (p = 0.003) and poor outcome (p = 0.0016). High TLR9 expression remained associated with poor outcome in multivariable analysis after adjusting for COO and other clinical features (OR = 3.36, 95% CI 1.41-8.04). In exploratory analyses, a decrease of cell growth in ABC cell lines following inhibition of TLR9 activity with ODN4084-F was suggested.

CONCLUSION

We conclude that TLR9 correlates with ABC/non-GCB phenotype and is a potential predictor of poor prognosis in DLBCL.

Male Sex, B Symptoms, Bone Marrow Involvement, and Genetic Alterations as Predictive Factors in Diffuse Large B-Cell Lymphoma

Approximately 40% of patients with diffuse large B-cell lymphoma (DLBCL) are not cured with first-line chemoimmunotherapy, resulting in poor prognosis. Schmitz et al. classified DLBCL into four prognostic genetic groups using whole-exome sequencing. We applied a simplified approach using a targeted next-generation sequencing assay (Archer FusionPlex Lymphoma Assay) to analyze samples from 105 patients-53 with a progression-free survival (PFS) < 2 years (the "Relapse group") and 52 with a PFS > 5 years (the "Remission group") following first-line systemic treatment. Patients were classified according to Schmitz et al. into the following categories: "MCD" (MYD88L265P and CD79B alteration), "N1" (NOTCH1 alteration), "BN2" (NOTCH2 alteration and BCL6 translocation), and "EZB" (EZH2 alteration and BCL2 translocation). The predictive value of this simplified genetic classification and of relevant clinical features were evaluated. The "Relapse group" included more patients classified as MCD and N1, while fewer were classified as EZB and BN2. Also, cell-of-origin (COO) characteristics and the size of N1 aligned with the classification of Schmitz et al. However, the limited sample size precludes definitive conclusions about the predictive value of our simplified approach. Additionally, male sex, B symptoms, and bone marrow involvement were associated with relapse. Therefore, these clinical features may be useful in predicting outcomes until an effective molecular classification is widely adopted.

Circulating tumor DNA as a powerful tool in diagnostics and treatment outcome prediction - focus on large B-cell lymphomas and follicular lymphomas

INTRODUCTION

Pathogenesis of large B-cell lymphomas (LBCL) and follicular lymphomas (FL) is a multistep process associated with the development of diverse DNA alterations and consequent deregulation of critical cellular processes. Detection of tumor-associated mutations within non-tumor compartments (mainly plasma) is the basis of the 'liquid biopsy' concept. Apart from tumor mutational profiling, quantitative analysis of circulating tumor DNA (ctDNA) allows longitudinal assessment of tumor burden. ctDNA-based technologies provide a new tool for tumor diagnostics and treatment personalization.

AREAS COVERED

Our review provides a comprehensive overview and summary of available ctDNA studies in LBCL and FL. The accuracy of ctDNA-based detection of lymphoma-associated DNA alterations is correlated to known LBCL and FL molecular landscape. Additionally, we summarized available evidence that supports and justifies the clinical use of ctDNA for lymphoma risk stratification, treatment response evaluation, and treatment response-adapted therapy. Lastly, we discuss other clinically important ctDNA applications: monitoring of lymphoma clonal evolution within resistance and/or relapse development and utilization of ctDNA for diagnostics in non-blood fluids and compartments (e.g. cerebrospinal fluid in primary CNS lymphomas).

EXPERT OPINION

Despite certain challenges, including methodological standardization, ctDNA holds promise to soon become an integral part of lymphoma diagnostics and treatment management.

The Role of EBV in the Pathogenesis of Diffuse Large B-Cell Lymphoma

There are multiple established risk factors for DLBCL; these risk factors share an underlying biology, which generally cause immune dysfunction, spanning immunosuppression to chronic inflammation. EBV is an established risk factor for DLBCL and approximately 10% of DLBCLs are EBV-positive. EBV is a ubiquitous infection, and it is thus among populations that are immunocompromised, by age or medically defined, where EBV-positive DLBCLs arise. In this chapter, we review the current classification, epidemiology, clinical, pathology, and molecular characteristics of EBV-positive DLBCL, and discuss the role of EBV in lymphoma tumorigenesis. We further discuss current and novel treatments aimed at the NFκB pathway and other targets.

Single-cell sequencing and spatial transcriptomics reveal FAS+ T cell and autophagy-related signatures predicting chemoimmunotherapy response in diffuse large B-cell lymphoma patients

Current subtyping methods of diffuse large B-cell lymphoma (DLBCL) could not satisfy the clinical demands for risk assessment and prognostic prediction. We aimed to investigate the prognostic effect of autophagy-related genes (ARGs) in DLBCL. Transcriptomic data of 1,409 DLBCL patients, 531 healthy controls (HCs), and single-cell sequencing data of 4 DLBCL were included. Validation involved spatial transcriptomics from 10 DLBCL patients and 110 DLBCL proteomic data from a local cohort. We identified 153 differentially expressed ARGs between DLBCL patients (n=48) and HCs (n=531), classifying 414 DLBCL patients into two subtypes based on autophagy heterogeneity. Subtype I, characterized by upregulated T regulatory (Treg) cells (P<0.0001) and T follicular helper (Tfh) cells (P=0.0012), showed a superior prognosis (P=0.035). Eight prognostic ARGs were selected to construct an autophagy-related model, dividing patients into low- and high-risk groups. Kaplan-Meier survival analysis revealed significantly better outcomes for the low-risk group in both the discovery (P<0.0001) and validation cohorts (P=0.0041). High-risk patients exhibited elevated IDO1 (P=0.042) and LAG3 (P<0.001) levels. Among the eight signature proteins, higher FAS was further verified to indicate a better prognosis in the local cohort (n=110) using antibody array (P=0.0083). FAS was primarily expressed in T cells such as Treg and Tfh cells and was elevated in non-progressive disease patients. FAS-positive T cells showed increased interferon-gamma (normalized enrichment score (NES)=2.196, FDR<0.0001) and alpha (NES=1.836, FDR<0.01) response activities. We constructed an autophagy-related model and identified FAS as a prognostic biomarker. FAS+ Treg and Tfh cell-enriched TME indicated a favorable prognosis.

Evaluation of Etiologic Heterogeneity for Risk of Diffuse Large B-Cell Lymphoma Subtype Defined by the Cell of Origin

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is clinically heterogeneous, and gene expression profiling has identified at least two biologically distinct DLBCL subtypes defined by their cell of origin (COO): germinal center B cell (GCB) and activate B cell (ABC) or non-GCB. We evaluated a variety of putative DLBCL risk factors for etiologic heterogeneity by the COO in a clinic-based study of newly diagnosed DLBCL cases (N = 638) and frequency-matched controls (N = 2,253).

METHODS

The COO was determined on formalin-fixed, paraffin-embedded tumor tissue, with DLBCL classified as GCB (N = 283), non-GCB (N = 188), or undetermined/missing (N = 167; mainly because of lack of tissue). Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

We identified heterogeneity by the COO for low socioeconomic status (SES), which was only associated with non-GCB DLBCL (OR = 1.88 for low vs. average SES; 95% CI, 1.08-3.27); alcohol use, which was only associated with GCB DLBCL (OR = 0.48 for former drinkers; 95% CI, 0.29-0.80 and OR = 0.47 for current drinkers; 95% CI, 0.32-0.71); and borderline heterogeneity for the regular use of regular/extra-strength aspirin, which was only associated with non-GCB DLBCL (OR = 0.36; 95% CI, 0.16-0.85). In contrast, there was no significant heterogeneity by the COO for family history, medical history, or other lifestyle factors.

CONCLUSIONS

Although requiring confirmation, most risk factors for DLBCL did not show etiologic heterogeneity by the COO, with some notable exceptions including alcohol use, SES, and perhaps regular use of regular/extra-strength aspirin showing associations.

IMPACT

Mechanistically, these findings suggest that most of the DLBCL risk factors evaluated here influence lymphomagenesis prior to differentiation into COO subtypes, with selected factors acting later.

Advances in the Classification of Aggressive B-cell Lymphomas

Aggressive B-cell lymphomas are a biologically and clinically very heterogeneous group of tumors that may be related to different stages of B-cell differentiation development. This review aims to summarize recent advances in the understanding of these tumors with a focus on the practical approach to the diagnosis of these entities. We analyze the defining characteristics of the different subtypes of aggressive B-cell lymphomas, including nodal and extranodal diffuse large B-cell lymphoma, virus-associated lymphomas, terminally differentiated B-cell lymphomas, high-grade B-cell lymphomas, and Burkitt lymphoma. This review particularly explores the integration of morphologic, immunophenotypic, and genetic data that refine diagnostic accuracy and prognostic stratification, underscoring the necessity for a standardized approach in clinical practice. By synthesizing current knowledge, this review aims to enhance the understanding of aggressive B-cell lymphomas within the context of the evolving classification system, paving the way for future research and clinical advancements.

Superior survival in diffuse large B cell lymphoma of the bone with immune rich tumor microenvironment

With tumor genomic and gene-expression profiling (GEP), this study investigated the immune-molecular signatures of a unique cohort of diffuse large B-cell lymphoma of the bone (bone-DLBCL), including primary bone (PB-DLBCL, n = 52) and polyostotic-DLBCL (n = 20), in comparison to nodal DLBCLs with germinal center B-cell (GCB) phenotype (nodal-DLBCL-GCB, n = 34). PB-DLBCL and polyostotic-DLBCL shared similar genomic profiles and transcriptomic signatures, justifying their collective analysis as bone-DLBCL. Differential incidences of EZH2, HIST1H1E, and MYC aberrations (p < 0.05) confirmed the distinct oncogenic evolution between bone-DLBCL and nodal-DLBCL-GCB. Differentially expressed genes were identified between bone-DLBCL and nodal-DLBCL-GCB (p < 0.001), substantiated by distinct gene-set enrichment analysis (GSEA). In contrast to a more 'depleted' phenotype for nodal-DLBCL-GCB, bone-DLBCL primarily exhibited an 'intermediate/rich' tumor microenvironment (TME) signature (p = 0.001), as determined by a previously published gene set. Unsupervised clustering defined two distinct groups that aligned with previously reported immune-enriched TME clusters: an 'immune-rich' cluster largely consisting of bone-DLBCLs (75%, p = 0.002) with superior survival (p = 0.030), and a poor-prognostic 'immune-low' cluster, including mostly nodal-DLBCL-GCB (61%). Single-sample (ss)GSEA showed higher scores for regulatory T cells, immunosuppressive/prolymphoma cytokines, and vascular endothelial cells in immune-rich samples (p < 0.001). Additionally, CIBERSORTx revealed a higher abundance of regulatory T cells and activated mast cells in the immune-rich cluster (p < 0.001). These findings were confirmed at protein level, where CD3 and FOXP3 immunochemistry showed significant overlap with the gene-expression data (p < 0.001). Conclusively, PB-DLBCL and polyostotic-DLBCL share immune-molecular TME characteristics, supporting their classification as a unified bone-DLBCL entity. The distinct immune-rich TME profile of bone-DLBCL associated with superior survival potentially shapes emerging immunomodulatory strategies.

TP53 mutation and immunohistochemical p53 expression characteristics in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) with TP53 mutations has specific clinicopathological features and is usually associated with a poor prognosis. TP53 gene mutations typically lead to aberrant expression patterns of the p53 protein. We studied 123 DLBCL patients at Henan Cancer Hospital, 35.8% (44/123) had TP53 mutations. Analysis of mutation sites in 44 cases of DLBCL patients revealed that the mutations primarily occur in the DNA-binding domain (DBD region) of the encoded p53 protein; among all mutation types, there were 8 truncation or frameshift mutations, and 36 missense mutations. Further, immunohistochemistry (IHC) detected expression levels of p53 protein in 123 DLBCL samples. The mutation results were used as a reference, and receiver operating characteristic (ROC) curve analysis was employed. Ultimately, the expression ratio of 65% and the moderate-strong expression intensity were regarded as the cut-off value, namely high p53 expression or p53 negative (<1%) indicated mutant-type p53 protein. the complete remission (CR) rate of the mutant-type p53 protein group after receiving R-CHOP regimen was 50% (14/28), and the objective response rate (ORR) was 75%, which differed significantly (P<0.01) compared with wild-type p53 protein group [CR rate of 75.86% (66/87) and ORR rate of 89.66%]. Common gene mutations in the mutant-type p53 protein group primarily involve alterations in pathways related to epigenetics, B cell antigen receptor signaling, cell cycle, among others. IHC analysis of the p53 protein is a simple and low-cost approach that can be employed to predict TP53 mutation status and therapy response.

Are there clinically relevant prognostic factors in diffuse large B-cell lymphoma beyond International Prognostic Index?

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) has variable prognosis, with only 50 to 60% of patients cured by standard first line treatment. Identifying patients unlikely to benefit from standard first line therapy is therefore crucial. Schmitz's study identified four molecular subtypes of DLBCL with differing prognoses: MCD, BN2, Nl, and EZB, with BN2 and EZB showing more favorable outcomes. This study aimed to evaluate the effectiveness of the Archer FusionPlex Lymphoma Assay in identifying the newly defined genetic subtypes of DLBCL, while also exploring the association between immunohistochemical (IHC) and next-generation sequencing (NGS) methods for classifying the cell of origin (COO) and assessing their predictive value for patient survival.

MATERIALS AND METHODS

We classified 131 DLBCL patients using Hans algorithm into GCB (germinal center B-cell-like) and ABC (activated B-cell-like) subtypes, and with NGS applying Archer FusionPlex lymphoma assay into ABC, GCB, unclassified, and into Schmitz's novel genetic subtypes. A mutational analysis of just 7 genes (MYD88L265P, CD79B, EZH2, NOTCH1, NOTCH2, BCL2, and BCL6) was used for genetic classification. Various statistical models were applied to assess survival differences between subtypes. Finally, STRATOS analysis was conducted to validate our preliminary statistical findings.

RESULTS

35.9% of patients were successfully classified into new genetic subtypes, with acceptable consistency between IHC and NGS method for COO determination. However, the new genetic subtype classification by NGS did not correlate with overall survival, nor did the COO classifications by IHC or NGS. The inclusion of these classifications also did not improve the predictive value of models compared to the basic model based on the International Prognostic Index (IPI) only.

CONCLUSIONS

The Archer FusionPlex Lymphoma assay showed a somewhat lower detection rate of novel genetic subtypes compared to reports based on exome sequencing, yet identified novel genetic subtypes in over one-third of patients. However, an in-depth STRATOS statistical analysis did not confirm its predictive value for DLBCL prognosis, likely due to factors like patient selection and sample size limitations.

Machine learning-based identification of cuproptosis-related lncRNA biomarkers in diffuse large B-cell lymphoma

Multiple machine learning techniques were employed to identify key long non-coding RNA (lncRNA) biomarkers associated with cuproptosis in Diffuse Large B-Cell Lymphoma (DLBCL). Data from the TCGA and GEO databases facilitated the identification of 126 significant cuproptosis-related lncRNAs. Various feature selection methods, such as Univariate Filtering, Lasso, Boruta, and Random Forest, were integrated with a Transformer-based model to develop a robust prognostic tool. This model, validated through fivefold cross-validation, demonstrated high accuracy and robustness in predicting risk scores. MALAT1 was pinpointed using permutation feature importance from machine learning methods and was further validated in DLBCL cell lines, confirming its substantial role in cell proliferation. Knockdown experiments on MALAT1 led to reduced cell proliferation, underscoring its potential as a therapeutic target. This integrated approach not only enhances the precision of biomarker identification but also provides a robust prognostic model for DLBCL, demonstrating the utility of these lncRNAs in personalized treatment strategies. This study highlights the critical role of combining diverse machine learning methods to advance DLBCL research and develop targeted cancer therapies.

How I diagnose high-grade B-cell lymphoma

OBJECTIVES

High-grade B-cell lymphoma (HGBL), introduced in the 2016 World Health Organization (WHO) revised fourth edition classification, included cases defined by MYC and BCL2 and/or BCL6 rearrangements or by high-grade morphology. Diagnostic criteria and nomenclature for these lymphomas were refined in the 2022 WHO fifth edition (WHO-5) classification and International Consensus Classification (ICC). This review describes our approach to the diagnosis of HGBL.

METHODS

Two cases are presented illustrating how we diagnose HGBL, including 1 case harboring MYC and BCL6 rearrangements and a second showing TdT expression in an HGBL with MYC and BCL2 rearrangements. The ways in which these cases are distinguished from other lymphomas with high-grade features and the appropriate nomenclature using WHO-5 and ICC classifications are emphasized.

RESULTS

An HGBL diagnosis requires integration of morphology, immunophenotype, and genetics and exclusion of other lymphomas with high-grade morphology, including Burkitt lymphoma, B-lymphoblastic leukemia/lymphoma (B-LBL/ALL), and blastoid mantle cell lymphoma. A diagnosis of HGBL/large B-cell lymphoma with 11q aberration should also be considered in certain patient populations.

CONCLUSIONS

High-grade B-cell lymphomas are subclassified based on morphologic and genetic features. There are differences in the nomenclature and definition of these lymphomas in the WHO-5 and ICC classifications. Distinguishing HGBLs from other mature B-cell lymphomas and B-LBL/ALL is critical so that patients receive appropriate treatment.

Structure of the nucleosome-bound human BCL7A

Proteins of the BCL7 family (BCL7A, BCL7B, and BCL7C) are among the most recently identified subunits of the mammalian SWI/SNF chromatin remodeler complex and are absent from the unicellular version of this complex. Their function in the complex is unknown, and very limited structural information is available, despite the fact that they are mutated in several cancer types, most notably blood malignancies and hence medically relevant. Here, using cryo-electron microscopy in combination with biophysical and biochemical approaches, we show that BCL7A forms a stable, high-affinity complex with the nucleosome core particle (NCP) through binding of BCL7A with the acidic patch of the nucleosome via an arginine anchor motif. This interaction is impaired by BCL7A mutations found in cancer. Further, we determined that BCL7A contributes to the remodeling activity of the mSWI/SNF complex and we examined its function at the genomic level. Our findings reveal how BCL7 proteins interact with the NCP and help rationalize the impact of cancer-associated mutations. By providing structural information on the positioning of BCL7 on the NCP, our results broaden the understanding of the mechanism by which SWI/SNF recognizes the chromatin fiber.

Molecular clustering on ctDNA improves the prognostic stratification of patients with DLBCL compared with ctDNA levels

ABSTRACT

Circulating tumor DNA (ctDNA) levels can help predict outcomes in diffuse large B-cell lymphoma (DLBCL), but its integration with DLBCL molecular clusters remains unexplored. Using the LymphGen tool in 77 DLBCL cases with both ctDNA and tissue biopsy, a 95.8% concordance rate in molecular cluster assignment was observed, showing the reproducibility of molecular clustering on ctDNA. A multicenter, prospective cohort of 166 patients with newly diagnosed DLBCL was analyzed for ctDNA levels and molecular clusters using cancer personalized profiling by deep sequencing. Patients with ctDNA levels of <2.5 log10 haploid genome equivalents (hGE)/mL had a 4-year progression-free survival (PFS) and overall survival (OS) of 71.7% and 85.7%, respectively, compared with 50.3% and 61.0% for those with higher ctDNA levels (P = .0018 and P = .0017). Recursive partitioning showed that patients with ctDNA levels of ≥2.5 log10 hGE/mL were further stratified by clusters ST2/BN2. In this group, ST2/BN2 patients associated with a favorable outcome with a 4-year PFS and OS of 87.5% and 100%, respectively, compared to 38.0% and 47.1% for other clusters (P = .003 and P = .001). Combining ctDNA levels and ST2/BN2 clusters improved outcome prediction. Low-risk patients (n = 51), characterized by ctDNA levels of <2.5 log10 hGE/mL and/or BN2/ST2 cluster, had a 4-year PFS and OS of 75.3% and 87.8%, respectively. High-risk patients (n = 115), with ctDNA levels of ≥2.5 log10 hGE/mL and no BN2/ST2 cluster, had a 4-year PFS and OS of 38.0% and 47.1%, respectively. Adding cluster assignment to ctDNA levels improved the model's C statistics (0.63 vs 0.59 for PFS; 0.68 vs 0.63 for OS). Liquid biopsy thus provides a multilayered approach for outcome prediction in DLBCL.

Epigenetic Symphony in Diffuse Large B-Cell Lymphoma: Orchestrating the Tumor Microenvironment

DLBCL is a testament to the complexity of nature. It is characterized by remarkable diversity in its molecular and pathological subtypes and clinical manifestations. Despite the strides made in DLBCL treatment and the introduction of innovative drugs, around one-third of patients face a relapse or develop refractory disease. Recent findings over the past ten years have highlighted the critical interplay between the evolution of DLBCL and various epigenetic mechanisms, including chromatin remodeling, DNA methylation, histone modifications, and the regulatory roles of non-coding RNAs. These epigenetic alterations are integral to the pathways of oncogenesis, tumor progression, and the development of therapeutic resistance. In the past decade, the identification of dysregulated epigenetic mechanisms in lymphomas has paved the way for an exciting field of epigenetic therapies. Crucially, these epigenetic transformations span beyond tumor cells to include the sophisticated network within the tumor microenvironment (TME). While the exploration of epigenetic dysregulation in lymphoma cells is thriving, the mechanisms affecting the functions of immune cells in the TME invite further investigation. This review is dedicated to weaving together the narrative of epigenetic alterations impacting both lymphoma cells with a focus on their infiltrating immune companions.

MYC networks associate with decreased CD8 T-cell presence in diffuse large B-cell lymphoma and may be addressed by the synergistic combination of AZD4573 and Selinexor - a preliminary analysis

Diffuse Large B-cell Lymphoma (DLBCL) is a genomically-heterogenous disease affecting over 70,000 patients per year that presents a clinical challenge despite the success of frontline regimens and second-line Chimeric Antigen receptor T-cell (CAR-T) therapy. Recently, genomic alterations and tumor microenvironment features associated with poor CAR-T response have been identified, with MYC amplification emerging in new analyses. This retrospective analysis aimed to integrate various data to identify genomic partnerships capable of providing added clarity and actionable treatment targets within this population. Publicly-available data were analyzed for differential expression based on MYC, 24-month event-free survival (EFS24) status, and CAR-T response. Notable T-cell partner genes such as IL7R (FDR = 0.00150) and CD58 (FDR = 5.375E-06) and cell death mediators such as PDCD1LG2 (FDR = 4.061E-06) were significantly lost in patients with High/Altered MYC that also failed EFS24. CD8 T-cell presence was also significantly lower in High/Altered MYC de-novo patients (p = 0.00112) and CAR-T non-responders (p = 0.00835). De-novo patients with both High/Altered MYC and CD8 T-cell absence faced a significantly inferior survival compared to counterparts with only one factor or neither (p = 0.0226). rrDLBCL patients reflected similar oncogenic pathways associated with greater scRNA MYC expression. In vitro application of the CDK9 inhibitor AZD4573 and XPO1 inhibitor Selinexor significantly reduced DLBCL cell line viability as single agents and produced synergistic results when applied in combination. Our analysis presents key associations between the MYC oncogene and depleted TME presence capable of providing clarity within the evolving precision CAR-T treatment landscape.

Case report of high-grade B-cell lymphoma with MYC and BCL2 rearrangements presenting as compartment syndrome of the leg

Background

Diffuse large B-cell lymphoma (DLBCL)/high-grade B-cell lymphoma with MYC and BCL2 rearrangements ("double-hit" lymphoma) is an uncommon subtype of mature B-cell lymphoma characterized by the concurrent rearrangements of MYC and BCL2 oncogenes. Rarely, aggressive high-grade lymphomas manifest as compartment syndrome, necessitating urgent surgical intervention. Here, we describe a case of high-grade B-cell lymphoma with an unusual presentation of compartment syndrome.

Case Description

A 68-year-old woman presented to the emergency room with increased swelling and pain in her right leg, was subsequently diagnosed with right thigh compartment syndrome, and underwent urgent fasciotomy followed by repeat debridement in the medical wound closure. Additionally, the patient was found to have inguinal and external iliac lymphadenopathy along with deep vein thrombosis (DVT). Her past medical history included human immunodeficiency virus (HIV) infection, which was well-controlled with bictegravir, emtricitabine, and tenofovir alafenamide. Excisional biopsy of the right thigh muscle and fluorescence in situ hybridization (FISH) analysis confirmed the diagnosis of high-grade B-cell lymphoma with MYC and BCL2 gene rearrangements arising in the setting of immunodeficiency/dysregulation (lymphoma associated with HIV infection). Despite aggressive medical management in the intensive care unit, the patient succumbed to the disease and ultimately died from sepsis and hemorrhagic shock.

Conclusions

High-grade B-cell lymphoma with MYC and BCL2 rearrangements represents an aggressive lymphoma with a poor prognosis. The unusual manifestation of this lymphoma involving skeletal muscle and presenting as compartment syndrome is rare. Unfortunately, the patient passed away shortly after undergoing debridement surgery. This case highlights the importance for clinicians to be vigilant and attentive to atypical presentations, as delays in diagnosis and treatment can have significant consequences. Early recognition and prompt intervention are crucial in saving the patient's life.

High-grade B-cell lymphoma, not otherwise specified: an LLMPP study

Molecular characterization of high-grade B-cell lymphoma, not otherwise specified (HGBCL-NOS), is hindered by its rarity, evolving definition, and poor diagnostic reproducibility. To address this challenge, we analyzed 92 HGBCL-NOS tumors collected across Lymphoma/Leukemia Molecular Profiling Project sites. Leveraging comparison cohorts of diffuse large B-cell lymphoma (DLBCL-NOS) and Burkitt lymphoma (BL), and molecular frameworks described in these entities, our analysis revealed a heterogenous molecular landscape, reminiscent of DLBCL-NOS but with an enrichment of BL features. By cell-of-origin, 59% were germinal center B-cell-like (GCB), and 25% were activated B-cell-like (ABC). LymphGen, a genetic classifier for DLBCL-NOS, assigned a genetic subtype to 34% of HGBCL-NOS. Although classification rate was lower than in DLBCL-NOS (66%), assigned subtypes spanned the spectrum of LymphGen classes, including 31% of ABCs classified as MCD. Features differentiating HGBCL-NOS from DLBCL-NOS included MYC -rearrangement (47% vs. 6%), dark zone signature (DZsig) expression (45% vs. 7%), and more frequent mutation of ID3 , MYC , CCND3 , and TP53 - all common to BL. A genetic classifier that differentiates DLBCL-NOS from BL classified 53% of DZsig+ tumors as BL-like, with those classified as DLBCL-like frequently BCL2 -rearranged. Among DZsig-GCB tumors, 95% were DLBCL-like. Centralized pathology review reclassified almost half of tumors as DLBCL-NOS but did not identify a more homogenous HGBCL-NOS population, with no difference in features between confirmed and reclassified tumors. In conclusion, molecular testing enables a subset of HGBCL-NOS to be assigned to established categories. Based on rarity and diagnostic challenges, broader inclusion of HGBCL-NOS should be considered in biomarker-driven DLBCL trials.

Key points

Molecular analyses reveal that HGBCL-NOS encompasses a heterogeneous collection of tumors.A subset of HGBCL-NOS can be assigned to established molecular groups, while others remain unclassified.

Next-generation sequencing guides diagnosis and treatment in a complex presentation of ALK-positive anaplastic large-cell lymphoma: a case report

Next-generation sequencing (NGS) technology is being increasingly utilized in the management of cancer patients due to its diagnostic, therapeutic, and prognostic value, and potential to inform use of targeted therapy. We report a case wherein performing NGS testing proved to be a critical component in diagnosis and therapeutic decision making. The case was of a patient who presented with diffuse osteolytic bone lesions that on biopsy showed an undifferentiated malignancy. A diagnosis of poorly differentiated sarcoma was made at an outside institution and carboplatin and paclitaxel was initiated. However, NGS testing revealed a TRAF1::ALK translocation, which led to a revised diagnosis of stage IV ALK-positive anaplastic large cell lymphoma (ALCL), a curable cancer. The patient then started treatment with brentuximab vedotin, cyclophosphamide, doxorubicin, etoposide, and prednisone followed by autologous stem cell transplantation consolidation, given the very extensive disease at presentation. She remains in continued complete remission at 28 months. In this case, NGS was essential in establishing the correct diagnosis and selection of therapy in high-risk ALCL. NGS testing should be a routine component of the oncology patient workup to complement standard diagnostic modalities.

Genetic subtyping by Whole Exome Sequencing across Diffuse Large B Cell Lymphoma and Plasmablastic Lymphoma

Diffuse Large B-Cell Lymphoma (DLBCL) is a heterogeneous disease characterized by a limited number of molecularly defined subtypes. Recently, genomic-based algorithms have been proposed for the classification of this disease. The whole exome sequencing was conducted on 108 diagnostic samples of diffuse large B-cell lymphoma (DLBCL). Somatic variants, predicted copy number alterations (CNAs), and available fusion data were utilized to classify the cases. Additionally, the enrichment of mutations in the TP53, MYC, and MAPK/ERK pathways was analyzed. Genetic subtypes were identified in approximately 55% of the cases. Cases with a specific genetic subtype exhibited a significantly higher Tumor Mutation Burden compared to molecularly unclassified cases (Mann-Whitney U test, p =  0.024). The prevalence of subtypes varied according to the cell of origin phenotypes. GC-B type DLBCL NOS were classified as EZB (5 cases, 16%), ST2 (5 cases, 16%), and BN2 (1 case, 3%). Four cases (13%) were genetically composite. Three cases of HGBCL/DLBCL double-hit (MYC & BCL2) were classified as EZB-MYC. Forty-three non-GC-B type DLBCL cases were classified as ST2 (5 cases, 11%), BN2 (6 cases, 14%), and MCD (3 cases, 7%). Nine cases were genetically composite (20%). MYC pathway mutations were enriched in cases with EZB and ST2 genetic features, while they were absent in the MCD subtype. TP53 mutations were identified in 11% of the cases. Plasmablastic lymphomas exhibit genetic diversity, with 27% of tumors classified as ST2. Recurrent somatic mutations indicate dysregulation of the JAK/STAT, MAPK/ERK, and tyrosine kinase signaling pathways.

Combined autologous hematopoietic stem cell transplantation and CD19 CAR T-cell therapy for relapsed/refractory diffuse large B-cell lymphoma with TP53 mutation: A case report

Despite advancements in the treatment of diffuse large B-cell lymphoma, including CAR T-cell therapy, TP53 mutations remain a significant negative prognostic factor in patients with relapsed/refractory diffuse large B-cell lymphoma. The combination of autologous stem cell transplantation and CAR T-cell therapy may enhance long-term prognosis and reduce adverse effects, including severe cytokine release syndrome. This case report presents a 41-year-old man with relapsed/refractory diffuse large B-cell lymphoma harboring TP53 mutations who underwent autologous stem cell transplantation combined with CD19 CAR T-cell therapy. Two years posttreatment, the patient remains in sustained complete remission, highlighting the potential efficacy of this combination approach for relapsed/refractory diffuse large B-cell lymphoma with TP53 mutation.

Multilevel Analysis of MYC and BCL2 Aberrations in Diffuse Large B-Cell Lymphoma: Identifying a High-Risk Patient Subgroup Across Cell-of-Origin Using Targeted Sequencing

INTRODUCTION

Diffuse large B-cell lymphoma (DLBCL) exhibits striking clinical and biological heterogeneity. Recent studies have identified new subgroups within germinal center B-cell like (GCB) DLBCL, associated with inferior prognosis, irrespective of MYC and BCL2 translocations. We explored the existence of such a DLBCL high-risk subgroup, based on multilevel aberrations, especially focusing on MYC and BCL2.

METHODS

Tissue samples from 111 DLBCL patients were sequenced with a 90-gene lymphoma panel, followed by integrative analyses combining sequencing data, immunohistochemistry, fluorescent in situ hybridization, and clinical data.

RESULTS

We identified a high-risk subgroup in DLBCL defined by: dual immunohistochemical MYC and BCL2 expression (DEL), concurrent MYC and BCL2 translocations (DHL-BCL2), mutations in MYC, CXCR4, or both, and/or BCL2 amplification. The high-risk subgroup constituted 41% of the cohort and included DHL-BCL2, DEL, a GCB subgroup likely representing the recently described GCB subgroups, and a subset of non-GCB patients. In multivariate analysis, high-risk features provided independent predictive value from age and IPI. The 5-year overall survival was 36% in high-risk patients, compared to 76% in non-high-risk patients.

CONCLUSION

We identified a distinct high-risk DLBCL subgroup, characterized by MYC and BCL2 aberrations, beyond conventional DHL-BCL2 and DEL, and irrespective of cell-of-origin, thereby expanding the poor-prognosis group.

TP53 Mutation Is the Only Robust Mutational Biomarker for Outcome Found in a Consecutive Clinical Cohort of Real-Word Patients With Primary Large B-Cell Lymphoma

INTRODUCTION

Large B-cell lymphoma (LBCL) taxonomy has moved in the direction of a molecular classification, but further clinical experience is needed. We present high-risk gene mutations, which predict outcome in an exploratory study of a consecutive real-world cohort of patients with primary LBCL treated with R-CHOP or R-CHOP-like therapy.

METHODS

The study was a Registry Study Research Project. Sixty-one patients with LBCL, who had a diagnostic tumor sample successfully examined with a 59-gene next-generation sequencing (NGS) panel as a part of routine clinical work, were included in an otherwise unselected cohort. Data were extracted from patient files and pathology reports.

RESULTS

Mutations in NOTCH2 (HR 9.69; 95% CI [2.46-38.11]; p = 0.0012), PRDM1 (HR 3.54; 95% CI [1.03-12.22]; p = 0.045), and TP53 (HR 5.89; 95% CI [1.71-20.32]; p = 0.005) were significantly associated with inferior survival in patients with primary LBCL treated with intention to cure with at least three series of R-CHOP or R-CHOP-like therapy. Neither MYD88 (HR 0.66; 95% CI (0.17-2.49), p = 0.54) nor CD79B (HR 0.84;95% CI (0.18-3.88), p = 0.82) mutations were associated with inferior survival.

CONCLUSION

With a targeted gene panel and NGS methodology feasible in daily diagnostic routine, we identified high-risk gene mutations with a significant prognostic impact of which TP53 mutations were reproducible across validation cohorts.

Age- and gender-specific molecular characteristics of diffuse large B-cell lymphoma: Results from clinical trials of the DSHNHL/GLA

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. Despite a high cure rate, too many patients show refractory (ref) or relapsed (rel) disease. This study examines the frequency of recurring gene mutations and their interplay with well-known biomarkers in female and male patients between 18 and 80 years with ref/rel DLBCL compared to patients with complete remission (CR) to identify biological risk factors associated with treatment response, using cohorts of R-CHOP-like treated DLBCL enrolled in clinical trials of the DSHNHL. The biomarker profile of patients differed between younger and elderly patients with ref/rel DLBCL, with a higher frequency of BCL2 translocations in younger patients, and higher numbers of ABC subtypes and MYC protein expression in the elderly. Amplicon sequencing revealed generally higher mutation frequencies in the younger cohort. Mutations in CREBBP and TNFRSF14 were associated with shorter overall survival (OS) only in younger patients. A higher proportion of GNA13 mutations was detected in female patients of the elderly DLBCL patient cohort, clearly emphasizing the striking differences in biomarker distribution between younger and elderly as well as female and male patients.

Understanding the intrinsic biology of diffuse large B-cell lymphoma: recent advances and future prospects

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoid tumor, and accounts for approximately 30-40% of non-Hodgkin lymphomas. Although the prognosis has significantly improved with the advent of rituximab combination chemotherapy in the early 2000s, recurrence still occurs in about 40% of cases. Even though chemotherapy with increased dose-intensity is used in recurrent cases, the prognosis of such patients remains poor. Thus, the development of personalized medicine, including molecular-targeted drugs, is required to improve the prognosis of DLBCL patients, and further understanding of the molecular pathogenesis of DLBCL is essential for this purpose. With recent advances in genetic analysis technology, unknown genetic abnormalities and gene expression patterns have been discovered, and based on these discoveries, progress is being made in elucidating and subdividing molecular pathologies. This article summarizes recent findings regarding molecular pathogenesis in DLBCL using transcriptome and genomics technologies, and outlines the path to personalized medicine.

Relapse-free survival in a pediatric patient with recurrent EZH2-mutant melanoma treated with adjuvant tazemetostat

Enhancer of zeste homolog 2 (EZH2) is an essential epigenetic regulator of H3K27 histone methylation and is mutated or overexpressed in a wide variety of cancers. In melanoma, EZH2 overexpression contributes to excessive trimethylation of H3K27 on tumor suppressor genes and has been proposed to be a mechanism of tumor progression and metastasis. EZH2-targeted therapies have been successfully used to treat patients with follicular lymphoma and epithelioid sarcoma, but their clinical use in melanoma has not been described. Here, we describe a pediatric patient with multiply relapsed melanoma harboring an EZH2 A692V missense mutation, treated adjuvantly with the EZH2 inhibitor tazemetostat, who experienced a prolonged relapse-free survival.

Multisite clinical cross-validation and variant interpretation of a next generation sequencing panel for lymphoid cancer prognostication

AIMS

Genomic sequencing of lymphomas is under-represented in routine clinical testing despite having prognostic and predictive value. Clinical implementation is challenging due to a lack of consensus on reportable targets and a paucity of reference samples. We organised a cross-validation study of a lymphoma-tailored next-generation sequencing panel between two College of American Pathologists (CAP)-accredited clinical laboratories to mitigate these challenges.

METHODS

A consensus for the genomic targets was discussed between the two institutes based on recurrence in diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, chronic lymphocytic leukaemia and T-cell lymphomas. Using the same genomic targets, each laboratory ordered libraries independently and a cross-validation study was designed to exchange samples (8 cell lines and 22 clinical samples) and their FASTQ files.

RESULTS

The sensitivity of the panel when comparing different library preparation and bioinformatic workflows was between 97% and 99% and specificity was 100% when a 5% limit of detection cut-off was applied. To evaluate how the current standards for variant classification of tumours apply to lymphomas, the Association for Molecular Pathology/American Society of Clinical Oncology/CAP and OncoKB classification systems were applied to the panel. The majority of variants were assigned a possibly actionable class or likely pathogenic due to more limited evidence in the literature.

CONCLUSIONS

The cross-validation study highlights the benefits of sample and data exchange for clinical validation and provided a framework for reporting the findings in lymphoid malignancies.

Diffuse large B cell lymphoma (DLBCL): epidemiology, pathophysiology, risk stratification, advancement in diagnostic approaches and prospects: narrative review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive subtype of non-Hodgkin's lymphoma that arises from the germinal center. It represents a heterogeneous disease characterized by different pathological, clinical, and molecular entities. Gene expression profiling based on the alleged cell of origin differentiates transcriptional subtypes such as germinal center and activated B cell-like. DLBCL accounts for around 40% of all non-Hodgkin's lymphomas worldwide. Its incidence generally increases with age. The international prognostic index remains the most important tool for disease stratification.The diagnosis of DLBCL is best made through an excisional biopsy of a suspicious lymph node. Nowadays, advanced techniques are employed to accurately diagnose and determine the clinical outcomes of patients. Immunohistochemistry, next-generation sequencing, and array-based comparative hybridization facilitate the global identification of diverse and numerous genetic alterations. However, further validation should be necessary to apply advanced techniques in clinical practice. In this review, we summarize the current literature and discuss the pathophysiology, epidemiology, and diagnostic advancements of DLBCL.

High Prevalence of MYD88 and CD79B Mutations in Primary Sinonasal Diffuse Large B-Cell Lymphoma : Identification of an MCD-like Subtype

Primary sinonasal diffuse large B-cell lymphoma (PSDLBCL) is a rare aggressive lymphoma. Recently, genetic classification using Next Generation Sequencing (NGS) demonstrated that PSDLBCL largely consists of the MCD genotype, which has a poor prognosis mainly driven by MYD88 L265P and CD79B gene abnormalities. This study investigated the prevalence and clinicopathological significance of MYD88 L265P and CD79B Y196 mutations using droplet digital PCR in 55 patients with PSDLBCL, as well as the translocation of BCL2 / BCL6 / c-Myc with FISH. We found mutations in MYD88 L265P (29/55, 52.7%) and CD79B Y196 (20/55, 36.4%). The MCD-like subtype, defined by the mutation of MYD88 and/or CD79B , was found in 32 out of 55 cases (58.2%). This subtype largely consists of non-GCB type (31/32, 96.9%; P <0.01) and double-expressor cases (20/32, 62.5%; P =0.01) compared with the MYD88 / CD79B co-wild type, with BCL6 translocation in a small subset (2/32, 6.3%) and no translocations of BCL2 (0/32) or c-Myc (0/32). The MCD-like subtype tended to relapse in specific sites such as the central nervous system, testis, and/or skin compared with the co-wild type ( P =0.03), showing poorer outcomes in overall survival ( P =0.02) and progression-free survival ( P =0.01). In conclusion, our study highlights a high prevalence of MYD88 and CD79B mutations in PSDLBCL, identifying an aggressive MCD-like subtype with a distinct relapse pattern. This molecular subclassification can be helpful for both prognostic prediction and therapeutic strategy in patients with PSDLBCL.

Mutational profile dynamics in follicular lymphoma and large cell transformation

AIMS

Follicular lymphoma (FL) is characterised by significant heterogeneity in both the clinical trajectories and the molecular profiles. This study aimed to investigate clonal dynamics in FL by analysing mutation profiles at various time points during the disease course including at histological transformation (HT), to gain insight into the mutational changes over time.

METHODS

We retrospectively analysed 76 biopsies from 25 patients, including 13 cases with three or more FL biopsies and 12 cases with subsequent HT. Hybrid capture-based Next-Generation Sequencing (NGS) with the EuroClonality-NGS DNA capture (EuroClonality-NDC) assay was used to examine clonal rearrangements and mutations.

RESULTS

A total of 204 (potentially) pathogenic mutations were identified. Only 40% of mutations remained stably present during a median follow-up period of 139 months (range 9-198). KMT2D and CREBBP were the most frequently mutated genes at diagnosis, exhibiting relative stability in follow-up biopsies. Conversely, EZH2 displayed a dynamic pattern of mutations gained and lost during the disease course. At HT, pathogenic mutations affecting B2M, MYC and TP53 emerged. Changes in mutational burden were observed in both FL-sequential and diagnosis-transformation cohorts, with more pronounced changes in the latter.

CONCLUSIONS

This real-world study provides insights into the complex molecular pathogenesis of FL and HT. As targeted therapies emerge as treatment modalities, mutational profiles could influence treatment decisions in the future. Therefore, recognising the significant changes occurring in the mutational landscape of FL throughout the disease course is crucial.

Integrating genetic subtypes with PET scan monitoring to predict outcome in diffuse large B-cell lymphoma

Next Generation Sequencing-based subtyping and interim- and end of treatment positron emission tomography (i/eot-PET) monitoring have high potential for upfront and on-treatment risk assessment of diffuse large B-cell lymphoma patients. We performed Dana Farber Cancer Institute (DFCI) and LymphGen genetic subtyping for the HOVON84 (n = 208, EudraCT-2006-005174-42) and PETAL (n = 204, EudraCT-2006-001641-33) trials retrospectively combined with DFCI genetic data (n = 304). For all R-CHOP treated patients (n = 592), C5/MCD- and C2/A53-subtypes show significantly worse outcome independent of the international prognostic index. For all subtypes, adverse prognostic value of i/eot-PET-positive status is confirmed. Consistent with frequent primary refractory disease, only 67% C2 patients become eot-PET-negative versus 81-88% for other subtypes. Indicative of high relapse rates, outcome of C5 i/eot-PET-negative patients remains significantly worse in HOVON-84, which trend validates in the PETAL and SAKK38-07 trials (NCT00544219). These results show the added value of integrated genetic subtyping and PET monitoring for prognostic stratification and subtype-specific trial design.

Influence of Organ-Specific Extranodal Involvement on Survival Outcomes in Stage IV Diffuse Large B-Cell Lymphoma

BACKGROUND

The prognostic significance of extranodal sites in stage IV diffuse large B-cell lymphoma (DLBCL) remains uncertain, making it challenging to select appropriate treatment strategies for individual patients. In this study, we aimed to evaluate the influence of different extranodal sites on prognosis in young patients with stage IV DLBCL who achieved complete remission (CR) following initial chemo-immunotherapy and to explore the potential of autologous hematopoietic stem cell transplantation (ASCT) as a consolidation treatment for specific patient subgroups.

METHODS

We retrospectively reviewed data from 119 patients with DLBCL aged < 60 years who achieved CR after chemo-immunotherapy between 2008 and 2020. Patient survival rates were analyzed in correlation with different extranodal sites using univariate and multivariate models. Additionally, we assessed the effect of ASCT on 5-year progression-free survival (PFS) and overall survival (OS) in patients with different extranodal sites involved.

STUDY DESIGN

A retrospective bicenter study.

RESULTS

Univariate analysis revealed a significant decrease in survival rates in patients with a Deauville score of 3 and those with extranodal DLBCL affecting the spleen, bone marrow, nasosinus, and liver. In multivariate analysis, only nasosinusal involvement remained a significant predictor of reduced OS. Patients with spleen involvement benefited significantly from ASCT in terms of 5-year PFS and OS, whereas those with nasosinusal involvement did not demonstrate any survival advantage with ASCT.

CONCLUSION

Our findings highlight the influence of specific extranodal sites on the prognosis of patients with stage IV DLBCL. The data indicate a clear need for precise patient stratification based on extranodal involvement for more effective treatment planning. Notably, patients with spleen involvement appear to benefit from ASCT, suggesting that this strategy could be useful in this subgroup. Further prospective studies are needed to confirm and incorporate these findings into clinical practice.

Genetic Manipulation and Extended Culture of Human Germinal Center B Cells to Model Lymphomagenesis

The germinal center (GC) is the stage of B cell differentiation that gives rise to a majority of B cell lymphomas. Here, we present an experimental coculture system for the ex vivo expansion and genetic manipulation of human GC B cells purified from discarded tonsil tissue. This system can be used to investigate the impact of defined genetic alterations, either individually or in combination, upon the growth and survival of human GC B cells in vitro. We provide examples of genetic combinations that lead to the immortalized growth of GC B cells in vitro, and others that result in malignant transformation in immunodeficient mice, allowing the creation of genetically bespoke, synthetic, human lymphoma models.

Analysis of Histologic, Immunohistochemical and Genomic Features of Large B Cell Lymphoma Tumors May Predict Response to Polatuzumab Vedotin Based Therapy in Patients With Relapsed/Refractory Disease

BACKGROUND

Large B cell lymphoma (LBCL) is the most common form of lymphoma. Polatuzumab vedotin (polatuzumab) is an effective therapy for patients diagnosed with LBCL; however, only limited information regarding pathologic features detected by clinical laboratory assays is available to determine which patients are most likely to benefit from polatuzumab based therapies.

PATIENTS AND METHODS

We collected data from real world patients with relapsed or refractory LBCL whose tumors underwent next generation sequencing and were treated with polatuzumab based therapy at a single large academic cancer center. Tumor and patient characteristics were analyzed to look for factors that predict response to polatuzumab based therapies.

RESULTS

We identified high grade B cell lymphoma (HGBL) -NOS or MYC/BCL2 histology and presence of MYC rearrangement as factors that predict inferior response to polatuzumab based therapy. Patients with germinal center B cell of origin (GCB COO) LBCL without these factors had a high response rate (73%) to polatuzumab based therapy.

CONCLUSION

In a single center real world retrospective analysis of R/R LBCL patients with available genomic data, polatuzumab based therapy may be less effective in patients with HGBL-NOS or MYC/BCL2 histology and MYC rearrangements, but not in patients with GCB COO LBCL without these features. Routine performance of more comprehensive pathologic analysis of tumors may inform the use of polatuzumab based therapy in patients with LBCL.

The prognostic significance of MYC/BCL2 double expression in DLBCL in the genetic classification era

Double expression (DE) is a World Health Organization-recognized adverse prognostic factor in diffuse large B-cell lymphoma (DLBCL). However, the prognostic value of DE in the genetic subtyping era and potential mechanisms remain to be explored. We enrolled 246 DLBCL patients diagnosed between December 2021 and September 2023 in a Jiangsu Province Hospital cohort and included 930 DLBCL patients from three published studies in an external cohort. Double-expression DLBCL (DEL) in the external cohort was mainly distributed in the OTHER subtype (42.0%), EZB subtype (28.3%), and MCD subtype (15.0%), whereas the MCD subtype exhibited the highest ratio of DEL. DEL was significantly related to unfavorable overall survival (OS) and progression-free survival (PFS) in DLBCL, but only in EZB and OTHER subtypes that DEL retained remarkably adverse impacts on survivals compared to non-DEL. We explored the prognostic value of clinical and genetic parameters in DEL patients and found only ST2 showed better OS than A53 in DEL patients, whereas the other subtypes showed no significant difference. DEL showed similarities with the MCD subtype in mutation profiles. Furthermore, RNA-sequencing analyses exhibited upregulation in tumor proliferation-related pathways in DEL patients, but downregulation in extracellular matrix organization, T-cell activation and proliferation, type II interferon production, and pathways associated with cell death might contribute to the poor outcomes of DEL patients.

Primary large B-cell lymphoma of the central nervous system: A reappraisal of CD5-positive cases based on clinical, pathological, and molecular evaluation

CD5 expression is seen in 5%-10% of de novo diffuse large B-cell lymphomas (DLBCLs). Primary large B-cell lymphoma of the central nervous system (PCNS-LBCL) also exhibits CD5 expression in a minority of cases, however, clinicopathological and molecular features remain largely unclarified. Here we present the clinical, molecular, and pathological features of 11 CD5-positive (+) PCNS-LBCL cases, occupying 6.7% of all 165 PCNS-LBCLs diagnosed in our institutions. While CD5+ systemic DLBCL has been recognized as a distinctive subgroup showing an aggressive clinical course, no obvious differences were found between CD5+ and CD5-negative subgroups among the present CNS patients clinically. MYD88 p.L265P and CD79B p.Y196 mutations were detected in eight (73%) and seven (64%) cases, respectively, supporting previous reports. Notably, the microenvironmental immune cells were universally PD-L1/CD274-positive, and the higher levels tended to present favorable overall survival, as already evidenced in the PCNS-LBCL series. In contrast, neoplastic PD-L1/CD274 expression was undetectable in all cases. Indeed, no structural variations or copy number alterations involving PD-1 ligands were detected by targeted-capture sequencing and fluorescence in situ hybridization. While further studies are warranted, we may have confirmed similarity between PCNS-LBCLs and intravascular large B-cell lymphomas from a molecular standpoint.

Molecular Features of Diffuse Large B-Cell Lymphoma Associated With Primary Treatment Resistance

Diffuse large B-cell lymphoma (DLBCL) patients that fail to achieve a complete metabolic response with frontline immunochemotherapy have a poor prognosis. Genomic profiling has led to a broader understanding of the molecular drivers in DLBCL, but it is unknown how well current classifiers identify patients that will experience primary treatment resistance (PTR). Using whole exome and RNA sequencing data from newly diagnosed DLBCL patients, we evaluated the genomic landscape of PTR and compared it to that of non-PTR DLBCL. We found a significant increase in the frequency of TP53 (34% vs. 15%, p = 0.005) and ARID1A mutations (21% vs. 7%, p = 0.007) in PTR cases, with pathway analysis further demonstrating a downregulation of TP53 and an increase in chromatin modifying pathways. These results suggest that TP53 and ARID1A may be key mediators of PTR and important pathways contributing to the poor outcomes. We found that the current molecular classifiers were unable to identify PTR cases at diagnosis. However, our newly identified high-risk signature identified 46% of PTR cases at diagnosis. Overall, these results contribute to our understanding of the genomic landscape of patients with primary treatment resistance.

Evolving molecular classification of aggressive B-cell lymphoma

This review aims to provide an overview of the latest developments in the classification and molecular understanding of aggressive B-cell lymphomas, specifically focusing on diffuse large B-cell lymphoma (DLBCL) and high-grade B-cell lymphoma (HGBL). Advances in molecular techniques have led to novel ways to classify these lymphomas based on clinical, histological, transcriptional, and genetic properties. While these methods have predominantly focused on the malignant compartment, recent studies emphasize the value of profiling the tumour microenvironment for a more comprehensive disease classification. Additionally, the integration of liquid biopsies represents a promising advancement, offering less invasive and dynamic insights into tumour characteristics and treatment response. Although molecular profiles are not yet routinely used to guide therapy, emerging data highlight their potential to predict responses to novel treatments. It is our belief that integrating molecular profiling and liquid biopsies into clinical practice and research now will pave the way for more personalized and effective therapies in the future.

Primary large B-cell lymphomas of immune-privileged sites

ABSTRACT

Diffuse large B-cell lymphoma (DLBCL) encompasses a diverse spectrum of aggressive B-cell lymphomas with remarkable genetic heterogeneity and myriad clinical presentations. Multiplatform genomic analyses of DLBCL have identified oncogenic drivers within genetic subtypes that allow for pathologic subclassification of tumors into discrete entities with shared immunophenotypic, genetic, and clinical features. Robust classification of lymphoid tumors establishes a foundation for precision medicine and enables the identification of novel therapeutic vulnerabilities within biologically homogeneous entities. Most cases of DLBCL involving the central nervous system (CNS), vitreous, and testis exhibit immunophenotypic features suggesting an activated B-cell (ABC) origin. Shared molecular features include frequent comutations of MYD88 (L265P) and CD79B and frequent genetic alterations promoting immune evasion, which are hallmarks of the MCD/C5/MYD88 genetic subtype of DLBCL. Clinically, these lymphomas primarily arise within anatomic sanctuary sites and have a predilection for remaining confined to extranodal sites and strong CNS tropism. Given the shared clinical and molecular features, the umbrella term primary large B-cell lymphoma of immune-privileged sites (IP-LBCL) was proposed. Other extranodal DLBCL involving the breast, adrenal glands, and skin are often ABC DLBCL but are more heterogeneous in their genomic profile and involve anatomic sites that are not considered immune privileged. In this review, we describe the overlapping clinical, pathologic, and molecular features of IP-LBCL and highlight important considerations for diagnosis, staging, and treatment. We also discuss potential therapeutic vulnerabilities of IP-LBCL including sensitivity to inhibitors of Bruton tyrosine kinase, immunomodulatory agents, and immunotherapy.

DLBCL: who is high risk and how should treatment be optimized?

ABSTRACT

Diffuse large B-cell lymphoma (DLBCL), not otherwise specified, is the most common subtype of large B-cell lymphoma, with differences in prognosis reflecting heterogeneity in the pathological, molecular, and clinical features. Current treatment standard is based on multiagent chemotherapy, including anthracycline and monoclonal anti-CD20 antibody, which leads to cure in 60% of patients. Recent years have brought new insights into lymphoma biology and have helped refine the risk groups. The results of these studies inspired the design of new clinical trials with targeted therapies and response-adapted strategies and allowed to identify groups of patients potentially benefiting from new agents. This review summarizes recent progress in identifying high-risk patients with DLBCL using clinical and biological prognostic factors assessed at diagnosis and during treatment in the front-line setting, as well as new treatment strategies with the application of targeted agents and immunotherapy, including response-adapted strategies.

The high-grade B-cell lymphomas: double hit and more

ABSTRACT

Both the 2022 World Health Organization Classification of Hematolymphoid Tumors, 5th Edition and the International Consensus Classification of lymphoma have refined the way we now approach high-grade B-cell lymphoma (HGBL) with MYC and BCL2 and/or BCL6 rearrangements moving the previous generation of classification a step forward. The unifying biology of MYC/BCL2 tumors has become clearer and their inferior prognosis confirmed compared with those with morphologic similar phenotypes but lacking the classifcation defining cytogenetic abnormalities. Fluorescent in situ hybridization testing has now become largely population based, and we have learned much from this. We can readily define molecular categories and apply these widely to clinical practice. Uncertainty has, however, been shed on the place of MYC/BCL6 translocations in defining a common disease group of double hit lymphoma due to biological heterogeneity. We have enhanced our knowledge of outcomes and the role of therapy intensification to overcome chemotherapy resistance in HGBL. For those patients failed by initial induction chemotherapy, immunotherapy approaches, including chimeric antigen receptor T-cell therapies, are improving outcomes. Novel inhibitors, targeting dysregulated oncogenic proteins, are being explored at pace. The rare, but difficult, diagnostic classification HGBL (not otherwise specified) remains a diagnosis of exclusion with limited data on an optimal clinical approach. The days of talking loosely of double- and triple-hit lymphoma are numbered as biology and outcomes may not be shared. This review synergizes the current data on biology, prognosis, and therapies in HGBL.

Genomic differences of patients with hematologic malignancies in different age groups

Hematologic malignancies cause significant morbidity/mortality in both children and young adults (CYAs) as well as older adults (OAs). Yet their biological underpinnings remain inadequately understood. Here, we analyzed clinical and genomic disparities between CYAs and OAs in various hematologic malignancies. We found substantial differences in clinical features such as patient sex, ethnicity, metastasis rates, and tumor subtypes. Genomically, most CYA hematologic malignancies indicated lower mutational burden. Subsequently, we identified differentially mutated genes (DMGs) with varying mutation rates between CYAs and OAs, noting fewer mutations in CYAs for most genes such as TP53, TET2, and DNMT3A. In contrast, several DMGs (i.e., NRAS, KRAS, SMARCA4, ID3, PTPN11, WT1, and KIT) were overrepresented in CYAs. We further investigated human protein interacting partners of these identified DMGs that were highly mutated in CYAs/OAs, respectively, and found significant differences in network topological and functional roles. Notably, CYA malignancies demonstrated extensive copy number alterations (CNAs) and more driver gene fusions. In particular, four CNA differential genes (i.e., ARID1B, MYB, TP53, and ESR1) were overrepresented as amplifications and deletions in CYAs and OAs, respectively. Ultimately, we demonstrated a landscape comparative view of clinically actionable genetic events in CYAs and OAs, providing clues for age-related personalized treatment.

Multi-Component, Time-Course screening to develop combination cancer therapies based on synergistic toxicity

Clinical trials in cancer are ideally built on a foundation of sound mechanistic rationale and well-validated drug activity in relevant disease models. The screening of approved and investigational drugs in cell-based phenotypic assays can provide evidence of drug activity, but alternative screening paradigms are needed to develop and optimize multidrug combination regimens. Here, we utilize in vitro screening outcomes across a panel of lymphoma cell lines to dissect the activity of four small-molecule drugs (Venetoclax, Ibrutinib, Prednisolone, and Lenalidomide) currently under investigation within ongoing clinical trials in lymphoma. Data from multiple concentration ranges and time points show that synergistic drug combinations promote apoptosis and cytotoxicity responses at concentrations and time points that are consistent with in vivo drug exposures. To fully map the interaction landscape of these agents in relevant cell models, we developed an in vitro assay format that facilitated time-course evaluations involving concurrent multidrug exposure which further highlighted rapid, synergistic apoptosis induction as a central engine for the activity of this multicomponent targeted therapy. In addition to several instances of exceptional drug+drug synergy, the genetically similar diffuse large B cell lymphoma models also displayed substantial heterogeneity in the degree of synergism between drug pairs. A parallel survey of chemotherapies exhibited limited combination benefit, supporting recent findings that multicomponent chemotherapy outcomes are driven by individual drug activity. Collectively, these data demonstrate how in vitro drug screening data can identify multidrug combinations that exploit drug synergy to overcome the functional diversity of human malignancies.

Decreased PU.1 expression in mature B cells induces lymphomagenesis

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma, accounting for 30% of non-Hodgkin lymphomas. Although comprehensive analysis of genetic abnormalities has led to the classification of lymphomas, the exact mechanism of lymphomagenesis remains elusive. The Ets family transcription factor, PU.1, encoded by Spi1, is essential for the development of myeloid and lymphoid cells. Our previous research illustrated the tumor suppressor function of PU.1 in classical Hodgkin lymphoma and myeloma cells. In the current study, we found that patients with DLBCL exhibited notably reduced PU.1 expression in their lymphoma cells, particularly in the non-germinal center B-cell-like (GCB) subtype. This observation suggests that downregulation of PU.1 may be implicated in DLBCL tumor growth. To further assess PU.1's role in mature B cells in vivo, we generated conditional Spi1 knockout mice using Cγ1-Cre mice. Remarkably, 13 of the 23 knockout mice (56%) showed splenomegaly, lymphadenopathy, or masses, with some having histologically confirmed B-cell lymphomas. In contrast, no wild-type mice developed B-cell lymphoma. In addition, RNA-seq analysis of lymphoma cells from Cγ1-Cre Spi1F/F mice showed high frequency of each monoclonal CDR3 sequence, indicating that these lymphoma cells were monoclonal tumor cells. When these B lymphoma cells were transplanted into immunodeficient recipient mice, all mice died within 3 weeks. Lentiviral-transduced Spi1 rescued 60% of the recipient mice, suggesting that PU.1 has a tumor suppressor function in vivo. Collectively, PU.1 is a tumor suppressor in mature B cells, and decreased PU.1 results in mature B-cell lymphoma development.

An interpretable survival model for diffuse large B-cell lymphoma patients using a biologically informed visible neural network

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL) and is characterized by high heterogeneity. Assessment of its prognosis and genetic subtyping hold significant clinical implications. However, existing DLBCL prognostic models are mainly based on transcriptomic profiles, while genetic variation detection is more commonly used in clinical practice. In addition, current clustering-based subtyping methods mostly focus on genes with high mutation frequencies, providing insufficient explanations for the heterogeneity of DLBCL. Here, we proposed VNNSurv (https://bio-web1.nscc-gz.cn/app/VNNSurv), a survival model for DLBCL patients based on a biologically informed visible neural network (VNN). VNNSurv achieved an average C-index of 0.72 on the cross-validation set (HMRN cohort, n = 928), outperforming the baseline methods. The remarkable interpretability of VNNSurv facilitated the identification of the most impactful genes and the underlying pathways through which they act on patient outcomes. When only the 30 highest-impact genes were used as genetic input, the overall performance of VNNSurv improved, and a C-index of 0.70 was achieved on the external TCGA cohort (n = 48). Leveraging these high-impact genes, including 16 genes with low (<5 %) alteration frequencies, we devised a genetic-based prognostic index (GPI) for risk stratification and a subtype identification method. We stratified the patient group according to the International Prognostic Index (IPI) into three risk grades with significant prognostic differences. Furthermore, the defined subtypes exhibited greater prognostic consistency than clustering-based methods. Broadly, VNNSurv is a valuable DLBCL survival model. Its high interpretability has significant value for precision medicine, and its framework is scalable to other diseases.