Double-hit and double-protein-expression lymphomas: aggressive and refractory lymphomas

Low NDRG2, regulated by the MYC/MIZ-1 complex and methylation, predicts poor outcomes in DLBCL patients

Diffuse large B-cell lymphoma (DLBCL) represents the most common tumor in non-Hodgkin's lymphoma. N-Myc downstream-regulated gene 2 (NDRG2) is a tumor suppressor highly expressed in healthy tissues but downregulated in many cancers. Although cell proliferation-related metabolism rewiring has been well characterized, less is known about the mechanism of metabolic changes with DLBCL. Herein, we investigated the expressions of NDRG2, MYC and Myc-interacting zinc finger protein 1 (MIZ-1) in seven human lymphoma (mostly DLBCLs) cell lines. NDRG2 expression was inversely correlated with the expressions of MYC and MIZ-1. Further, we explored the regulatory mechanism and biological functions underlying the lymphomagenesis involving NDRG2, MYC and MIZ-1. MYC and MIZ-1 promoted DLBCL cell proliferation, while NDRG2 induced apoptosis in LY8 cells. Moreover, NDRG2 methylation was reversed by the 5-Aza-2'-deoxycytidine (5-Aza-CDR) treatment, triggering the downregulation of MYC and inhibiting DLBCL cell survival. MYC interacts with NDRG2 to regulate energy metabolism associated with mTOR. Remarkably, supporting the biological significance, the converse correlation between NDRG2 and MYC was observed in human DLBCL tumor tissues (R = -0.557). Bioinformatics analysis further validated the association among NDRG2, MYC, MIZ-1, mTOR, and related metabolism genes. Additionally, NDRG2 (P = 0.001) and MYC (P < 0.001) were identified as promising prognostic biomarkers in DLBCL patients through survival analysis. Together, our data demonstrate that the MYC/MIZ-1 complex interplays with NDRG2 to influence the proliferation and apoptosis of DLBCL cells and show the characterizations of NDRG2, MYC and MIZ-1 for metabolism features and prediction prognosis in DLBCL.

Navigating between Scylla and Charybdis: A roadmap to do better than Pola-RCHP in DLBCL

In treating diffuse large B-cell lymphoma (DLBCL), oncologists have traditionally relied on the chemotherapy backbone of R-CHOP as standard of care. The two dangers that the hematologist must navigate between are the aggressive disease (Charybdis that in the absence of therapy systematically destroys all the ships) and the toxicity of the therapies (Scylla with its six monstrous heads that devours six crew members at a time), and hematologists have to navigate very carefully between both. Therefore, three different strategies were employed with the goal of improving cure rates: de-escalating regimens, escalating regimens, and replacement strategies. With a replacement strategy, a breakthrough in treatment was identified with polatuzumab vedotin (anti-CD79B antibody/drug conjugate) plus R-CHP. However, this regimen still did not achieve the elusive universal cure rate. Fortunately, advances in genomic and molecular technologies have allowed for an improved understanding of the heterogenous molecular nature of the disease to help develop and guide more targeted, precise, and individualized therapies. Additionally, new pharmaceutical technologies have led to the development of novel cellular therapies, such as chimeric antigen receptor (CAR) T-cell therapy, that could be more effective, while maintaining an acceptable safety profile. Thus, we aim to highlight the challenges of DLBCL therapy as well as the need to address therapeutic regimens eventually no longer tethered to a chemotherapy backbone. In the intersection of artificial intelligence and multi-omics (genomics, epigenomics, transcriptomics, proteomics, metabolomics), we propose the need to analyze multidimensional biologic datato launch a decisive attack against DLBCL in a targeted and individualized fashion.

Prognostic evaluation of system immune-inflammatory index and prognostic nutritional index in double expressor diffuse large B-cell lymphoma

Predicting MYC and BCL2 double-expressor lymphoma prognosis using the system immune-inflammatory index (SII) and prognostic nutritional index (PNI) (DEL). From January 2015 to December 2021, 281 diffuse large B-cell lymphoma (DLBCL) wax blocks were used to make tissue chips. Screening double expressor lymphoma (DEL) instances involved immunocytochemistry and fluorescence in situ hybridization. Academic analysis used clinicopathological characteristics and follow-up data. SII, PNI, and DEL prognosis were correlated using univariate and multivariate cox regression analysis. The median age of 78 DEL patients is 60 (range: 43-74). SII and PNI cut-off values of 603.5, 3.07, and 144 predict PFS and OS well. Lower SII is associated with longer PFS (HR for SII = 0.34, 95% CI 0.15-0.76, P = 0.006; HR for NLR = 0.46, 95% CI 0.22-0.99, P = 0.048; HR for PLR = 0.39, 95% CI 0.17-0.94, P = 0.025; LMR = 0.39, 95%, CI 0.17-0.94, P = 0.025) and OS (HR for SII = 0.16, 95% CI 0.05-0.51, P = 0.005; HR for PNI = 0.20, 95% CI 0.06-0.62, P = 0.002). SII and PNI are promising predictors for twofold expressor DLBCL. Combining these increase prediction accuracy.

Myc rearrangement and concurrent high protein expression of C-Myc/Bcl2 carry an adverse prognosis in diffuse large B-cell lymphoma

PURPOSE

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of non-Hodgkin lymphoma, characterized by a variety of clinicopathological, histomorphological, immunophenotypic, and molecular genetic features. The subtype of DLBCL known as double-expressor lymphoma (DEL) is associated with an adverse prognosis when treated with R-CHOP. Our study aimed to investigate the clinicopathologic features of DEL and the prognostic roles of Myc rearrangement and C-Myc expression in DEL patients.

PATIENTS AND METHODS

We conducted a retrospective study of 145 patients who were identified through fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) testing.

RESULTS

We found that DEL patients were more likely to have a non-germinal center B-cell (GCB) subtype, stage III/IV disease, and a high International Prognostic Index (IPI) score. Our survival analysis indicated that Myc rearrangement and C-Myc expression were associated with poor prognosis. Although DEL patients with Myc rearrangement exhibited trends towards worse survival compared with patients without Myc rearrangement, the differences were not statistically significant (P = 0.4008). The median overall survival (OS) of DEL patients with ≥70 % C-Myc expression (DEL-C-Mychigh) was 5 months. In the DEL-C-Mychigh group, the non-GCB subtype showed nonsignificant trends towards poorer survival compared with the GCB subtype (P = 0.1042).

CONCLUSION

In conclusion, our study shows that a cut-off of ≥70 % for C-Myc expression in DEL patients can improve risk stratification, and suggests that more intensive treatment regimens may be necessary to improve survival in this high-risk population.

α-KG inhibits tumor growth of diffuse large B-cell lymphoma by inducing ROS and TP53-mediated ferroptosis

Metabolic reprogramming is a hallmark of human malignancies. Dysregulation of glutamine metabolism is essential for tumorigenesis, microenvironment remodeling, and therapeutic resistance. Based on the untargeted metabolomics sequencing, we identified that the glutamine metabolic pathway was up-regulated in the serum of patients with primary DLBCL. High levels of glutamine were associated with inferior clinical outcomes, indicative of the prognostic value of glutamine in DLBCL. In contrast, the derivate of glutamine alpha-ketoglutarate (α-KG) was negatively correlated with the invasiveness features of DLBCL patients. Further, we found that treatment with the cell-permeable derivative of α-KG, known as DM-αKG, significantly suppressed tumor growth by inducing apoptosis and non-apoptotic cell death. Accumulation of a-KG promoted oxidative stress in double-hit lymphoma (DHL), which depended on malate dehydrogenase 1 (MDH1)-mediated 2-hydroxyglutarate (2-HG) conversion. High levels of reactive oxygen species (ROS) contributed to ferroptosis induction by promoting lipid peroxidation and TP53 activation. In particular, TP53 overexpression derived from oxidative DNA damage, further leading to the activation of ferroptosis-related pathways. Our study demonstrated the importance of glutamine metabolism in DLBCL progression and highlighted the potential application of α-KG as a novel therapeutic strategy for DHL patients.

Patterns of Oncogene Coexpression at Single-Cell Resolution Influence Survival in Lymphoma

Cancers often overexpress multiple clinically relevant oncogenes, but it is not known if combinations of oncogenes in cellular subpopulations within a cancer influence clinical outcomes. Using quantitative multispectral imaging of the prognostically relevant oncogenes MYC, BCL2, and BCL6 in diffuse large B-cell lymphoma (DLBCL), we show that the percentage of cells with a unique combination MYC+BCL2+BCL6- (M+2+6-) consistently predicts survival across four independent cohorts (n = 449), an effect not observed with other combinations including M+2+6+. We show that the M+2+6- percentage can be mathematically derived from quantitative measurements of the individual oncogenes and correlates with survival in IHC (n = 316) and gene expression (n = 2,521) datasets. Comparative bulk/single-cell transcriptomic analyses of DLBCL samples and MYC/BCL2/BCL6-transformed primary B cells identify molecular features, including cyclin D2 and PI3K/AKT as candidate regulators of M+2+6- unfavorable biology. Similar analyses evaluating oncogenic combinations at single-cell resolution in other cancers may facilitate an understanding of cancer evolution and therapy resistance.

SIGNIFICANCE

Using single-cell-resolved multiplexed imaging, we show that selected subpopulations of cells expressing specific combinations of oncogenes influence clinical outcomes in lymphoma. We describe a probabilistic metric for the estimation of cellular oncogenic coexpression from IHC or bulk transcriptomes, with possible implications for prognostication and therapeutic target discovery in cancer. This article is highlighted in the In This Issue feature, p. 1027.

HDAC inhibitor chidamide synergizes with venetoclax to inhibit the growth of diffuse large B-cell lymphoma via down-regulation of MYC, BCL2, and TP53 expression

Diffuse large B-cell lymphoma (DLBCL) is an aggressive type of non-Hodgkin's lymphoma. A total of 10%‒15% of DLBCL cases are associated with myelocytomatosis viral oncogene homolog(MYC) and/or B-cell lymphoma-2 (BCL2) translocation or amplification. BCL2 inhibitors have potent anti-tumor effects in DLBCL; however, resistance can be acquired through up-regulation of alternative anti-apoptotic proteins. The histone deacetylase (HDAC) inhibitor chidamide can induce BIM expression, leading to apoptosis of lymphoma cells with good efficacy in refractory recurrent DLBCL. In this study, the synergistic mechanism of chidamide and venetoclax in DLBCL was determined through in vitro and in vivo models. We found that combination therapy significantly reduced the protein levels of MYC, TP53, and BCL2 in activated apoptotic-related pathways in DLBCL cells by increasing BIM levels and inducing cell apoptosis. Moreover, combination therapy regulated expression of multiple transcriptomes in DLBCL cells, involving apoptosis, cell cycle, phosphorylation, and other biological processes, and significantly inhibited tumor growth in DLBCL-bearing xenograft mice. Taken together, these findings verify the in vivo therapeutic potential of chidamide and venetoclax combination therapy in DLBCL, warranting pre-clinical trials for patients with DLBCL.

CAR T-Based Therapies in Lymphoma: A Review of Current Practice and Perspectives

While more than half of non-Hodgkin lymphomas (NHL) can be cured with modern frontline chemoimmunotherapy regimens, outcomes of relapsed and/or refractory (r/r) disease in subsequent lines remain poor, particularly if considered ineligible for hematopoietic stem cell transplantation. Hence, r/r NHLs represent a population with a high unmet medical need. This therapeutic gap has been partially filled by adoptive immunotherapy. CD19-directed autologous chimeric antigen receptor (auto-CAR) T cells have been transformative in the treatment of patients with r/r B cell malignancies. Remarkable response rates and prolonged remissions have been achieved in this setting, leading to regulatory approval from the U.S. Food and Drug Administration (FDA) of four CAR T cell products between 2017 and 2021. This unprecedented success has created considerable enthusiasm worldwide, and autologous CAR T cells are now being moved into earlier lines of therapy in large B cell lymphoma. Herein, we summarize the current practice and the latest progress of CD19 auto-CAR T cell therapy and the management of specific toxicities and discuss the place of allogeneic CAR T development in this setting.

Significance of Single-cell Level Dual Expression of BCL2 and MYC Determined With Multiplex Immunohistochemistry in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a fatal heterogenous neoplasm. Recent clinical trials have failed partly due to nebulous criteria for defining high-risk patients. Patients with double-expresser lymphoma (DEL) have a poor prognosis and are resistant to conventional treatment. However, many diagnostic and clinical controversies still surround DEL partly due to the arbitrariness of criteria for the diagnosis of DEL. In this study, we suggest a refined method for diagnosing DEL by evaluating the concurrent expression of BCL2 and MYC at the single-cell level (dual-protein-expressing lymphoma [DUEL]). For the proof of concept, a multiplex immunofluorescence assay for CD20, BCL2, and MYC was performed and quantitatively analyzed using spectral image analysis in patients. The analysis results and clinical applicability were verified by using dual-color immunohistochemistry performed on 353 independent multicenter patients who had been uniformly treated with standard therapy. DUEL showed significantly worse overall survival (OS) and event-free survival (EFS) (P=0.00011 and 0.00035, respectively). DUEL status remained an independent adverse prognostic variable with respect to the International Prognostic Index risk and the cell of origin. Moreover, the advantage of determining DUEL status by dual-color immunohistochemistry was shown by more robust classification and more homogeneous high-risk subgroup patient identification in both training (n=271) (OS: P<0.0001; EFS: P<0.0001) and validation sets (n=82) (OS: P=0.0087; EFS: P<0.0001). This concept of DUEL is more consistent with carcinogenesis and has greater practical utility, hence it may provide a better basis for both basic and clinical research for the development of new therapeutics.

Liquid biopsy in diffuse large B-cell lymphoma: utility in cell origin determination and survival prediction in Chinese patients

The utility of circulating tumor DNA (ctDNA) in classifying the cell origin of diffuse large B-cell lymphoma (DLBCL) has not been explored in the Chinese population. In this study, we aimed to investigate the genetic characteristics of DLBCL based on both tumor and ctDNA sequencing and to assess the predictive value of ctDNA in DLBCL. A targeted sequencing panel of 413 genes was applied to tumor biopsies and paired plasma samples obtained from 30 patients with DLBCL before therapeutic intervention (pretreatment). The concordance between plasma genotyping classification and traditional cell-of-origin classification using tumor tissue was 80.0% (20/25). Patients with higher baseline plasma ctDNA levels had poorer survival compared to those with lower ctDNA levels (2-year progression survival rate: 40.0% vs. 80.0%, p = 0.011; 5-year overall survival rate: 30.5% vs. 70.0%, p = 0.004). Collectively, our results demonstrated that pretreatment ctDNA analysis could assist origin determination and prognosis prediction clinically.

AID is a poor prognostic marker of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements

Diffuse large B-cell lymphoma with MYC rearrangement is defined as double/triple-hit lymphoma (DHL/THL) or single-hit lymphoma (SHL) by the inclusion of the BCL2 and BCL6 rearrangements status. DHL/THL is called as "high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements" in the World Health Organization 2017 Classification of Tumors of Hematopoietic and Lymphoid Tissues. To find a prognostic biomarker of DHL/THL, we firstly examined 19 cases (molecular analysis series;10 cases of DHL/THL and 9 cases of SHL) with gene expression profile analysis. The gene expression profile analysis showed that the high expression of AICDA was associated with an adverse prognosis in DHL/THL, but not in SHL. Then, we evaluated immunohistochemical expression of AID, the protein product of AICDA, in 50 cases (molecular analysis series of 19 cases and additional immunohistochemistry series of 31 cases; 12 cases of DHL/THL and 19 cases of SHL) and confirmed that its expression was also associated with an adverse prognosis in DHL/THL. Therefore, AICDA and AID can be a predictor of an adverse clinical outcome in DHL/THL and immunohistochemistry of AID is useful to find DHL/THL-adverse prognosis group.

Mouse Models of Germinal Center Derived B-Cell Lymphomas

Over the last decades, the revolution in DNA sequencing has changed the way we understand the genetics and biology of B-cell lymphomas by uncovering a large number of recurrently mutated genes, whose aberrant function is likely to play an important role in the initiation and/or maintenance of these cancers. Dissecting how the involved genes contribute to the physiology and pathology of germinal center (GC) B cells -the origin of most B-cell lymphomas- will be key to advance our ability to diagnose and treat these patients. Genetically engineered mouse models (GEMM) that faithfully recapitulate lymphoma-associated genetic alterations offer a valuable platform to investigate the pathogenic roles of candidate oncogenes and tumor suppressors in vivo, and to pre-clinically develop new therapeutic principles in the context of an intact tumor immune microenvironment. In this review, we provide a summary of state-of-the art GEMMs obtained by accurately modelling the most common genetic alterations found in human GC B cell malignancies, with a focus on Burkitt lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma, and we discuss how lessons learned from these models can help guide the design of novel therapeutic approaches for this disease.

CD5+ diffuse large B-cell lymphoma: a narrative review

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous entity, and cell surface cluster of differentiation (CD) 5 expression may represent a distinct subset. Here, we provide a narrative review of CD5+ DLBCL to understand its clinical implications. Between 5-10% of DLBCL express CD5, making it an uncommon subset. Studies have variably shown that CD5+ DLBCL may be associated with increased age, high lactate dehydrogenase, B symptoms, extra-nodal sites, higher International Prognostic Index score, and advanced stage. CD5+ DLBCLs are more likely to express Bcl-2, MYC, and MUM1; a large proportion exhibit an activated B-cell (ABC)-like phenotype. The balance of studies generally supports an independent prognostic value of CD5 in DLBCL While more aggressive first-line regimens have been advocated for CD5+ DLBCL, including dose-adjusted R-EPOCH and autologous stem cell transplant, evidence to support these approaches is lacking; further study is warranted to identify the optimal treatment strategy for this disease entity.

Fluorescent nanoparticle-mediated semiquantitative MYC protein expression analysis in morphologically diffuse large B-cell lymphoma

The current World Health Organization (WHO) classification defines a new disease entity of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, making fluorescence in situ hybridization (FISH) screening for these genes mandatory. In addition, the prognostic significance of MYC expression was reported, with a cut-off value of 40%. However, interobserver discrepancies arise due to the heterogeneous intensity of MYC expression by immunohistochemistry. Moreover, a cut-off value of positivity for MYC protein in diffuse large B-cell lymphoma (DLBCL) varies among studies at present. Here, we applied a high-sensitivity semiquantitative immunohistochemical technique using fluorescent nanoparticles called phosphor-integrated dots (PID) to evaluate the MYC expression in 50 de novo DLBCL cases, and compared it with the conventional diaminobenzidine (DAB)-developing system. The high MYC expression detected by the PID-mediated system predicted poor overall survival in DLBCL patients. However, we found no prognostic value of MYC protein expression for any cut-off value by the DAB-developing system, even if the intensity was considered. These results indicate that the precise evaluation of MYC protein expression can clarify the prognostic values in DLBCL, irrespective of MYC rearrangement.

Comprehensive Characterization of Cachexia-Inducing Factors in Diffuse Large B-Cell Lymphoma Reveals a Molecular Subtype and a Prognosis-Related Signature

Background

Cachexia is defined as an involuntary decrease in body weight, which can increase the risk of death in cancer patients and reduce the quality of life. Cachexia-inducing factors (CIFs) have been reported in colorectal cancer and pancreatic adenocarcinoma, but their value in diffuse large B-cell lymphoma (DLBCL) requires further genetic research.

Methods

We used gene expression data from Gene Expression Omnibus to evaluate the expression landscape of 25 known CIFs in DLBCL patients and compared them with normal lymphoma tissues from two cohorts [GSE56315 (n = 88) and GSE12195 (n = 136)]. The mutational status of CIFs were also evaluated in The Cancer Genome Atlas database. Based on the expression profiles of 25 CIFs, a single exploratory dataset which was merged by the datasets of GSE10846 (n = 420) and GSE31312 (n = 498) were divided into two molecular subtypes by using the method of consensus clustering. Immune microenvironment between different subtypes were assessed via single-sample gene set enrichment analysis and the CIBERSORT algorithm. The treatment response of commonly used chemotherapeutic drugs was predicted and gene set variation analysis was utilized to reveal the divergence in activated pathways for distinct subtypes. A risk signature was derived by univariate Cox regression and LASSO regression in the merged dataset (n = 882), and two independent cohorts [GSE87371 (n = 221) and GSE32918 (n = 244)] were used for validation, respectively.

Results

Clustering analysis with CIFs further divided the cases into two molecular subtypes (cluster A and cluster B) associated with distinct prognosis, immunological landscape, chemosensitivity, and biological process. A risk-prognostic signature based on CCL2, CSF2, IL15, IL17A, IL4, TGFA, and TNFSF10 for DLBCL was developed, and significant differences in overall survival analysis were found between the low- and high-risk groups in the training dataset and another two independent validation datasets. Multivariate regression showed that the risk signature was an independently prognostic factor in contrast to other clinical characteristics.

Conclusion

This study demonstrated that CIFs further contribute to the observed heterogeneity of DLBCL, and molecular classification and a risk signature based on CIFs are both promising tools for prognostic stratification, which may provide important clues for precision medicine and tumor-targeted therapy.

Ibrutinib combined with venetoclax for the treatment of relapsed/refractory diffuse large B cell lymphoma

Treatment outcomes of relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL) are far from satisfactory. Certain efficacy of ibrutinib has been observed in non-GCB subtype DLBCL patients. This study aimed to investigate the efficacy and safety of ibrutinib plus BCL2 inhibitor venetoclax in R/R DLBCL patients with non-GCB subtype and BCL2 overexpression. Combinational therapy (ibrutinib 560mg/day; venetoclax started 1 week later, oral dose increased from 100 to 400mg/day in 3 weeks) was conducted, and one cycle was 4 weeks. Both drugs were stopped when disease progress or serious adverse reactions appear. The primary end-point was overall response rate (ORR) at two cycles. From December 2018 to July 2020, a total of 13 patients were treated with the combined therapy. Among them, eleven (84.6%) patients previously received at least two treatment regimens, eight (61.5%) patients were C-myc and BCL2 double expression. The ORR at two cycles was 61.5%, with 3 (23.1%) patients achieved complete remission (CR) and 5 (38.4%) patients achieved partial remission (PR). The ORR at four cycles and six cycles was 53.8% and 46.2%, respectively. The median duration of response was 11 months (range, 1.5-13.6 months). The median progression-free survival and overall survival were 5.6 months (range, 0.4-15.6) and 11.3 months (range, 2.8-17.2), respectively. The most common adverse event was grade 1/2 neutropenia (53.8%), and nonhematologic toxicities included Grade1/2 diarrhea (46.2%) and elevated liver enzymes (30.8%). Combined therapy of ibrutinib and venetoclax showed promising efficacy and synergistic effects in R/R DLBCL patients with non-GCB subtype and BCL2 overexpression, and the toxicities were well-tolerated.

CS2164 and Venetoclax Show Synergistic Antitumoral Activities in High Grade B-Cell Lymphomas With MYC and BCL2 Rearrangements

High-grade B-cell lymphoma with concurrent MYC and BCL2 rearrangements (HGBL-DHL) is a rare, aggressive mature B-cell malignancy with a high likelihood of treatment failure following front-line immunochemotherapies. Patients with HGBL-DHL who develop a relapsed or refractory disease have little effective therapeutic strategies and show very poor clinical outcomes, thus calling for development of novel therapies for this specific patient population. In this study, we investigated the preclinical anti-lymphoma efficacies and potential mechanism of action of a novel treatment approach, combining the BCL2 inhibitor venetoclax with CS2164, a new orally active multitarget inhibitor, in HGBL-DHL models. This combination therapy exhibited a robust synergistic cytotoxicity against HGBL-DHL cells, evidenced by cooperatively inducing loss of cell viability and promoting cell apoptosis. Moreover, coadministration of CS2164 and venetoclax resulted in significant superior suppression of HGBL-DHL cell growth and remarkably abrogated tumor burden in a HGBL-DHL-xenografted mouse model. The synergistic lethality of CS2164 and venetoclax in HGBL-DHL cells was associated with induction of DNA damage and impairment of DNA repair ability. Of importance, the combined treatment almost abolished the expression of both BCL2 and MYC, two hallmark proteins of HGBL-DHL, and substantially blunted the activity of PI3K/AKT/mTOR signaling cascade. In addition, MCL1 and BCL-XL, two well-characterized contributors for venetoclax resistance, were significantly lessened in the presence of CS2164 and venetoclax, thus leading to the accumulation of proapoptotic proteins BAX and PUMA and then initiating the intrinsic apoptosis pathway. Taken together, these findings suggest that the regimen of CS2164 and venetoclax is highly effective to eliminate HGBL-DHL cells in the preclinical setting, warranting further clinical investigations of this regimen for the treatment of unfavorable HGBL-DHL patients.

Simultaneous Discordant B-Lymphoblastic Lymphoma and Follicular Lymphoma

OBJECTIVES

We report a rare case of B-lymphoblastic lymphoma (B-LBL) and low-grade follicular lymphoma (FL) identified concurrently in biopsies from different sites at the initial diagnosis in a 39-year-old man. The clonal relationship between the 2 histologic subtypes was investigated.

METHODS

A diagnosis of FL grade 1/2 (low grade) was made by bone marrow (BM) biopsy. B-LBL was identified in biopsies from the testis and pancreas. Cytogenetic and molecular analyses were performed to investigate their clonal relationship.

RESULTS

Interphase fluorescence in situ hybridization analyses and G-banding karyotype analyses identified the BCL2-IGH and MYC-IGH translocation in tumor cells from both the BM and testis. The tumor cells from the BM and testis shared the same IGH VDJ usage and a high degree of somatic mutations. These findings suggest that acquisition of MYC gene rearrangement is a critical event for lymphoblastic transformation of FL. Of note, the presence of intraclonal diversity in the B-LBL sample further suggests an earlier or concurrent event of MYC translocation than the somatic IGH mutation in the germinal center and the dedifferentiation of lymphoma cells to a precursor stage of B-cell development.

CONCLUSIONS

B-lymphoblastic transformation of FL can occur with MYC gene rearrangement.

Circulating long non-coding RNAs HOTAIR, Linc-p21, GAS5 and XIST expression profiles in diffuse large B-cell lymphoma: association with R-CHOP responsiveness

The reliable identification of diffuse large B-cell lymphoma (DLBCL)-specific targets owns huge implications for its diagnosis and treatment. Long non-coding RNAs (lncRNAs) are implicated in DLBCL pathogenesis; however, circulating DLBCL-related lncRNAs are barely investigated. We investigated plasma lncRNAs; HOTAIR, Linc-p21, GAS5 and XIST as biomarkers for DLBCL diagnosis and responsiveness to R-CHOP therapy. Eighty-four DLBCL patients and thirty-three healthy controls were included. Only plasma HOTAIR, XIST and GAS5 were differentially expressed in DLBCL patients compared to controls. Pretreatment plasma HOTAIR was higher, whereas GAS5 was lower in non-responders than responders to R-CHOP. Plasma GAS5 demonstrated superior diagnostic accuracy (AUC = 0.97) whereas a panel of HOTAIR + GAS5 superiorly discriminated responders from non-responders by ROC analysis. In multivariate analysis, HOTAIR was an independent predictor of non-response. Among patients, plasma HOTAIR, Linc-p21 and XIST were correlated. Plasma GAS5 negatively correlated with International Prognostic Index, whereas HOTAIR positively correlated with performance status, denoting their prognostic potential. We constructed the lncRNAs-related protein-protein interaction networks linked to drug response via bioinformatics analysis. In conclusion, we introduce plasma HOTAIR, GAS5 and XIST as potential non-invasive diagnostic tools for DLBCL, and pretreatment HOTAIR and GAS5 as candidates for evaluating therapy response, with HOTAIR as a predictor of R-CHOP failure. We provide novel surrogates for future predictive studies in personalized medicine.

Integrative genomic analysis focused on cell cycle genes for MYC-driven aggressive mature B-cell lymphoma

MYC is a transcriptional factor that regulates growth and proliferation through cell cycle pathways. MYC alterations, in particular MYC rearrangements, are important in assessing the prognosis of aggressive B-cell lymphoma. In this study, we focused on the impact of nine major cell cycle genes for MYC-driven aggressive mature B-cell lymphoma and analyzed the mutational status using targeted next generation sequencing. Our 40 cases of aggressive mature B-cell lymphomas included 5 Burkitt lymphomas, 17 high-grade B-cell lymphomas and 18 diffuse large B-cell lymphomas with MYC breaks in 100%, 88% and 11%, respectively. Our data allowed a molecular classification into four categories partially independent from the histopathological diagnosis but correlating with the Ki-67 labelling index: (I) harboring TP53 and CDKN2A mutations, being highly proliferative, (II) with MYC rearrangement associated with MYC and/or ID3 mutations, being highly proliferative, (III) with MYC rearrangement combined with additional molecular changes, being highly proliferative, and (IV) with a diverse pattern of molecular alterations, being less proliferative. Taken together, we found that mutations of TP53, CDKN2A, MYC and ID3 are associated with highly proliferative B-cell lymphomas that could profit from novel therapeutic strategies.

Diagnostic Approach for Double-Hit and Triple-Hit Lymphoma Based on Immunophenotypic and Cytogenetic Characteristics of Bone Marrow Specimens

BACKGROUND

High-grade B-cell lymphoma with rearrangements of MYC and BCL2 and/or BCL6 (BCL2/BCL6), also known as double-hit lymphoma (DHL) and/or triple-hit lymphoma (THL), is a new entity of B-cell lymphoma in the 2017 WHO Classification. We retrospectively investigated D/THL and their clinico-laboratory features among cases of large B-cell lymphoma involving the bone marrow (BM), including diffuse large B-cell lymphoma, Burkitt lymphoma, and B-cell lymphomas with medium to large lymphoid cells, by additional FISH analysis of BM aspirates.

METHODS

A total of 111 patients diagnosed with aggressive B-cell lymphomas or B-cell lymphoma involving the BM with medium to large-sized malignant lymphocytes were reviewed from January 2000 to January 2018. Patients with available BM aspirates were evaluated by immunophenotyping by flow cytometry, chromosome, and FISH analysis for MYC and/or BCL2/BCL6 rearrangements.

RESULTS

In total, 23/111 (20.7%) showed MYC rearrangement, and eight (7.2%) were reclassified as D/THL on BM after FISH analysis for MYC and BCL2/BCL6. The detection of CD5(-)/CD10(+) based on flow cytometry was strongly associated with D/THL. A complex karyotype with aberrations related to regions in MYC and BCL2/BCL6 was significantly associated with D/THL. When the MYC FISH results of 28 BM aspirates and formalin-fixed paraffin-embedded tissue specimens were compared, 14% were discrepant.

CONCLUSIONS

Immunophenotypic and cytogenetic characteristics facilitate the diagnosis of D/THL in the cases with BM-involving aggressive B-cell lymphomas.

EHMT2 inhibitor BIX-01294 induces endoplasmic reticulum stress mediated apoptosis and autophagy in diffuse large B-cell lymphoma cells

Despite advancement in the treatment of diffuse large B-cell lymphoma (DLBCL), many patients tend to relapse or become refractory after initial therapy. Therefore, it is essential to identify novel therapeutic targets and drugs, understand the molecular pathogenesis mechanism of DLBCL, and find ways to prevent and treat relapsed or refractory DLBCL. BIX-01294 is a small molecule compound that specifically inhibits EHMT2 activity. In this study, we demonstrate that BIX-01294 triggered the inhibition of human DLBCL cell proliferation, lead to G₁ phase arrest via increasing P21 level and reducing cyclin E level. BIX-01294 also induced apoptosis via endogenous and exogenous apoptotic pathways. Moreover, BIX-01294 triggered autophagy and activated ER stress in human DLBCL cells. Furthermore, we showed that both key components of ER stress, ATF3, and ATF4, are required for BIX-01294-induced apoptosis and autophagy. Hence, this study provides new evidence that EHMT2 may be a new therapeutic target, and BIX-01294 may be a potential therapeutic drug for treating DLBCL.

RNA-Based next generation sequencing complements but does not replace fluorescence in situ hybridization studies for the classification of aggressive B-Cell lymphomas

Aggressive B-cell lymphomas are currently classified based in part upon the presence or absence of translocations involving BCL2, BCL6, and MYC. Most clinical laboratories employ fluorescence in situ hybridization (FISH) analysis for the detection of these rearrangements. The potential role of RNA-based sequencing approaches in the evaluation of malignant lymphoma is currently unclear. In this study, we performed RNA sequencing (RNAseq) in 37 cases of aggressive B-cell lymphomas using a commercially available next generation sequencing assay and compared results to previously performed FISH studies. RNAseq detected 1/7 MYC (14%), 3/8 BCL2 (38%) and 4/8 BCL6 (50%) translocations identified by FISH. RNAseq also detected 1 MYC/IGH fusion in a case not initially tested by FISH due to low MYC protein expression and 2 BCL6 translocations that were not detected by FISH. RNAseq identified the partner gene in each detected rearrangement, including a novel EIF4G1-BCL6 rearrangement. In summary, RNAseq complements FISH for the detection of rearrangements of BCL2, BCL6 and MYC in the evaluation and classification of aggressive B-cell lymphomas by detecting rearrangements that may be cryptic by FISH methods and by identifying the rearrangement partner genes. Detection of these clinically important translocations may be optimized by combined use of FISH and RNAseq.

Ofatumumab, Etoposide, and Cytarabine Intensive Mobilization Regimen in Patients with High-risk Relapsed/Refractory Diffuse Large B-Cell Lymphoma Undergoing Autologous Stem Cell Transplantation

BACKGROUND

More than one-half of high-risk patients with relapsed/refractory (rr) diffuse large B-cell lymphoma (DLBCL) relapse after autologous hematopoietic cell transplantation (auto-HCT). In this phase II study, we investigate the long-term outcomes of high-risk patients with rrDLBCL receiving intensive consolidation therapy (ICT) with OVA (ofatumumab, etoposide, and high-dose cytarabine) prior to auto-HCT.

PATIENTS AND METHODS

The primary endpoints were the ability of OVA to mobilize peripheral stem cells and the 2-year progression-free survival (PFS) rate following OVA. Secondary endpoints included safety, 2-year overall survival (OS), impact of cell of origin (COO), and the prognostic utility of next-generation sequencing minimal residual disease (MRD) testing. We simultaneously retrospectively assessed the outcomes of DLBCL patients who underwent ICT with a similar regimen at our institution.

RESULTS

Twenty-seven patients received salvage chemotherapy, with a response rate of 25% in patients with germinal center B-cell (GCB)-DLBCL versus 92% in patients with non-GCB-DLBCL (P = .003). Nineteen responding patients underwent ICT with OVA (100% successful stem cell mobilization). The 2-year PFS and OS rate was 47% and 59%, respectively, with no difference based on COO. Similar findings were observed when the study and retrospective cohorts were combined. Neutropenia was the most common toxicity (47%). MRD-negative patients at the completion of salvage had a median OS of not reached versus 3.5 months in MRD-positive patients (P = .02).

CONCLUSIONS

OVA followed by auto-HCT is effective and safe for high-risk rrDLBCL. Patients with GCB-DLBCL had a lower response to salvage chemotherapy, but no difference in outcomes based on COO was seen after auto-HCT. MRD testing in the relapsed setting was predictive of long-term survival.

R-CHOP resistance in diffuse large B-cell lymphoma: biological and molecular mechanisms

Although the first-line rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone regimen (R-CHOP) substantially improved outcomes for patients with diffuse large B-cell lymphoma (DLBCL), 40% of the patients suffered from relapsed/refractory disease and had poor survival outcomes. The detailed mechanism underlying R-CHOP resistance has not been well defined. For this review, we conducted a thorough search for literature and clinical trials involving DLBCL resistance. We discussed DLBCL biology, epigenetics, and aberrant signaling of the B-cell receptor (BCR), phosphatidylinositol 3-kinase (PI3K)/Akt, nuclear factor kappa light chain enhancer of activated B-cells (NF-κB), and the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathways as defining mechanisms of DLBCL heterogeneity and R-CHOP resistance. The cell of origin, double- or triple-hit lymphoma and double-protein-expression, clonal evolution, tumor microenvironment, and multi-drug resistance help to contextualize DLBCL resistance in an (epi)genetically and biologically comparative manner. With better understanding of the biological and molecular landscape of DLBCL, a more detailed classification system and tailored treatments will ideally become available to further improve the prognosis of DLBCL patients.

Molecular Genetics of Relapsed Diffuse Large B-Cell Lymphoma: Insight into Mechanisms of Therapy Resistance

The majority of patients with diffuse large B-cell lymphoma (DLBCL) can be treated successfully with a combination of chemotherapy and the monoclonal anti-CD20 antibody rituximab. Nonetheless, approximately one-third of the patients with DLBCL still experience relapse or refractory (R/R) disease after first-line immunochemotherapy. Whole-exome sequencing on large cohorts of primary DLBCL has revealed the mutational landscape of DLBCL, which has provided a framework to define novel prognostic subtypes in DLBCL. Several studies have investigated the genetic alterations specifically associated with R/R DLBCL, thereby uncovering molecular pathways linked to therapy resistance. Here, we summarize the current state of knowledge regarding the genetic alterations that are enriched in R/R DLBCL, and the corresponding pathways affected by these gene mutations. Furthermore, we elaborate on their potential role in mediating therapy resistance, also in connection with findings in other B-cell malignancies, and discuss alternative treatment options. Hence, this review provides a comprehensive overview on the gene lesions and molecular mechanisms underlying R/R DLBCL, which are considered valuable parameters to guide treatment.

MYC Activity Inference Captures Diverse Mechanisms of Aberrant MYC Pathway Activation in Human Cancers

c-MYC (MYC) is deregulated in more than 50% of all cancers. While MYC amplification is the most common MYC-deregulating event, many other alterations can increase MYC activity. We thus systematically investigated MYC pathway activity across different tumor types. Using a logistic regression framework, we established tumor type-specific, transcriptomic-based MYC activity scores that can accurately capture MYC activity. We show that MYC activity scores reflect a variety of MYC-regulating mechanisms, including MYCL and/or MYCN amplification, MYC promoter methylation, MYC mRNA expression, lncRNA PVT1 expression, MYC mutations, and viral integrations near the MYC locus. Our MYC activity score incorporates all of these mechanisms, resulting in better prognostic predictions compared with MYC amplification status, MYC promoter methylation, and MYC mRNA expression in several cancer types. In addition, we show that tumor proliferation and immune evasion are likely contributors to this reduction in survival. Finally, we developed a MYC activity signature for liquid tumors in which MYC translocation is commonly observed, suggesting that our approach can be applied to different types of genomic alterations. In conclusion, we developed a MYC activity score that captures MYC pathway activity and is clinically relevant. IMPLICATIONS: By using cancer type-specific MYC activity profiles, we were able to assess MYC activity across many more tumor types than previously investigated. The range of different MYC-related alterations captured by our MYC activity score can be used to facilitate the application of future MYC inhibitors and aid physicians to preselect patients for targeted therapy.

Immunophenotypic Landscape and Prognosis of Diffuse Large B-Cell Lymphoma with MYC/BCL2 Double Expression: An Analysis of A Prospectively Immunoprofiled Cohort

Simple Summary

Diffuse large B-cell lymphoma (DLBCL) with MYC/BCL2 double-expression (DE), a recently proposed poor prognostic group, can be easily identified by immunohistochemistry in routine clinical practice. However, clinical outcomes of DE-DLBCL patients vary immensely after R-CHOP immunochemotherapy and prognostic impact of MYC/BCL2-DE was conflicting according to the cell-of-origin, i.e., between germinal center-B-cell (GCB)- and non-GCB-DLBCLs. This implies the heterogeneity within DE-DLBCLs and emphasizes a need for proper risk stratification to select the patients who require more intensive therapy. By analyzing a prospectively immunoprofiled cohort of consecutively diagnosed DLBCL patients, we confirmed the poor prognostic value of MYC/BCL2-DE in DLBCL patients treated with R-CHOP irrespective of the cell-of-origin and international prognostic index. DE-DLBCLs with a concurrent risk factor, especially, elevated serum lactate dehydrogenase (LDH), had the worst survival and DE-DLBCL patients with normal LDH had clinical outcomes similar to those of non-DE-DLBCL patients. Risk stratification of DE-DLBCL based on serum LDH may guide clinical decision-making for DE-DLBCL patients.

Abstract

Diffuse large B-cell lymphoma (DLBCL) patients with MYC/BCL2 double expression (DE) show poor prognosis and their clinical outcomes after R-CHOP therapy vary immensely. We investigated the prognostic value of DE in aggressive B-cell lymphoma patients (n = 461), including those with DLBCL (n = 417) and high-grade B-cell lymphoma (HGBL; n = 44), in a prospectively immunoprofiled cohort. DE was observed in 27.8% of DLBCLs and 43.2% of HGBLs (p = 0.058). DE-DLBCL patients were older (p = 0.040) and more frequently exhibited elevated serum LDH levels (p = 0.002), higher international prognostic index (IPI; p = 0.042), non-germinal-center B-cell phenotype (p < 0.001), and poor response to therapy (p = 0.042) compared to non-DE-DLBCL patients. In R-CHOP-treated DLBCL patients, DE status predicted poor PFS and OS independently of IPI (p < 0.001 for both). Additionally, in DE-DLBCL patients, older age (>60 years; p = 0.017), involvement of ≥2 extranodal sites (p = 0.021), bone marrow involvement (p = 0.001), high IPI (p = 0.017), CD10 expression (p = 0.006), poor performance status (p = 0.028), and elevated LDH levels (p < 0.001) were significantly associated with poor OS. Notably, DE-DLBCL patients with normal LDH levels exhibited similar PFS and OS to those of patients with non-DE-DLBCL. Our findings suggest that MYC/BCL2 DE predicts poor prognosis in DLBCL. Risk stratification of DE-DLBCL patients based on LDH levels may guide clinical decision-making for DE-DLBCL patients.

MiR-7e-5p downregulation promotes transformation of low-grade follicular lymphoma to aggressive lymphoma by modulating an immunosuppressive stroma through the upregulation of FasL in M1 macrophages

BACKGROUND

In follicular lymphoma (FL), histologic transformation to high-grade FL and diffuse large B-cell lymphoma (DLBCL) is a critical adverse step in disease progression. Activation of the oncogene c-MYC and tumor microenvironment remodeling account for FL progression. A panel of microRNA (miRNA) was downregulated in transformed FL (tFL).

METHODS

Differentially expressed miRNAs were systematically compared in 11 lymph nodes from patients at different stages of disease. Expression of miR-7e-5p was analyzed in 46 B-cell lymphomas, including 30 FL tissues and 16 DLBCL tissues. In FL cells, transcriptional regulation of the oncogene c-MYC on its target miR-7e-5p was revealed by Chromatin Immunoprecipitation (ChIP) assay. Exosome, carrying differentially expressed miR-7e-5p was isolated and visualized by transmission electron microscope and fluorescence tracing. The effect of miR-7e-5p on recipient macrophage was determined by target gene quantification, flow cytometry, and TUNEL method in a cocultured system with miR-7e-5p-mimics or inhibitors treatment. Expression of miR-7e-5p targets, macrophage proportions, and clinical parameters were included for correlation analysis.

RESULTS

We determined that downregulation of miR-7e-5p, driven by c-MYC overexpression, was associated with poorer prognosis in FL patients. The decreased expression of miR-7e-5p in lymphoma cells led to a reduced exosomal transfer to surrounding macrophages. As a result, the target gene of miR-7e-5p, Fas ligand (FasL), was upregulated and activated the caspase signaling, which led to the apoptosis of M1 macrophages in tumor stroma. Finally, in transformed FL tissues, overexpression of FasL and activation of caspase proteins was detected in tumor stromal macrophages. Downregulation of miR-7e-5p was associated with poorer clinical outcomes.

CONCLUSION

Downregulation of exosomal miR-7e-5p induces stromal M1 macrophage apoptosis, which leads to immunosurveillance and transformation of FL.

Biomarkers and novel therapeutic approaches for diffuse large B-cell lymphoma in the era of precision medicine

Despite the great efforts for better treatment options for diffuse large B-cell lymphoma (DLBCL) (most common form of non-Hodgkin lymphoma, NHL) to treat and prevent relapse, it continues to be a challenge. Here, we present an overview of DLBCL and address the diagnostic assays and molecular techniques used in its diagnosis, role of biomarkers in detection, treatment of early and advanced stage DLBCL, and novel drug regimens. We discuss the significant biomarkers that have emerged as essential tools for stratifying patients according to risk factors and for providing insights into the use of more targeted and individualized therapeutics. We discuss techniques such as gene expression studies, including next-generation sequencing, which have enabled a more understanding of the complex pathogenesis of DLBCL and have helped determine molecular targets for novel therapeutic agents. We examine current treatment approaches, outline the findings of completed clinical trials, and provide updates for ongoing clinical trials. We highlight clinical trials relevant to the significant fraction of DLBCL patients who present with complex cases marked by high relapse rates. Supported by an increased understanding of targetable pathways in DLBCL, clinical trials involving specialized combination therapies are bringing us within reach the promise of an effective cure to DLBCL using precision medicine. Optimization of therapy remains a crucial objective, with the end goal being a balance between high survival rates through targeted and personalized treatment while reducing adverse effects in DLBCL patients of all subsets.

Double Hit and Double Expresser Diffuse Large B Cell Lymphoma Subtypes: Discrete Subtypes and Major Predictors of Overall Survival

Double hit lymphomas (DHL) and double expresser lymphomas (DEL) are subsets of diffuse large B cell lymphomas (DLBCL) which are being increasingly recognised as cause of treatment failure. This emphasizes the need for their separation from other DLBCL cases in order to prognosticate and administer more aggressive treatment to this set of patients. The present study was conducted with the aim to identify the DHL/DEL patients and study their distinctive clinicopathological profile and overall survival. This retrospective analysis involved 172 cases of DLBCL sub-classified on the basis of cell of origin. Immunohistochemical (IHC) analysis for MYC, BCL2, BCL6, MUM1 and CD10 was performed. Rearrangement studies were performed using break apart Fluorescent in situ hybridization. Overall survival (OS) was also evaluated. Distinctive clinical and pathological features of DHL and DEL were identified. Rearrangement study by FISH revealed seven cases of DHL (MYC + BCL2 &/or BCL6 rearrangement). Also, 20 patients (11.6%) showed a concurrent expression of BCL2 and MYC oncoproteins (DEL) on IHC. Most (6/7) DHL patients were double expressors also. The DHL patients demonstrated a significant association with female gender, high serum LDH levels (> 750 U/L) and GCB phenotype. DEL patients contrarily predominated amongst males, had intermediate LDH levels (251-500 U/L) and non GCB phenotype. The OS of the patients was 63.8% at 4 years. The OS of the DLBCL, DEL and DHL patients was 71.9%, 46.9%, and 0%, respectively at 4 years (p value 0.010). In case of DEL subtype, factors such as age < 60 years (66.7%), male sex (60.8%), nodal localization (52.5%), early disease stage (84.6%), low IPI score (60%), absence of B symptoms (50%), LDH < 250 U/L (80%) and GCB phenotype (53.3%) were associated with better OS. Further, the OS of DHL cases was 0% at 4 years. Double hit and double expresser lymphomas have poor prognostic outcomes and should be separated from DLBCL. All DELs should be tested for DHLs and especially those with immunoblastic morphology. DHL and DEL subtypes delineate the subtypes with inferior OS and reinstate the need for aggressive interventions.

Mechanism and Treatment of Rituximab Resistance in Diffuse Large Bcell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype B non-Hodgkin lymphoma in adults. After rituximab being introduced to treat DLBCL, the current first-line treatment is R-CHOP regimen. This regimen greatly improves patient's prognosis, however, relapsed or refractory cases are commonly seen, mainly due to the resistance to rituximab. Although a large number of experiments have been conducted to investigate rituximab resistance, the exac mechanisms and solutions are still unclear. This review mainly explores the possible mechanisms oft rituximab resistance and current new effective treatments for rituximab resistance in DLBCL.

Analysis of primary central nervous system large B-cell lymphoma in the era of high-grade B-cell lymphoma: Detection of two cases with MYC and BCL6 rearrangements in a cohort of 12 cases

High-grade diffuse large B-cell lymphoma (HG-DLBCL) refers to DLBCL with MYC and BCL2 and/or BCL6 rearrangements (double-hit or triple-hit DLBCL) that exhibits poor prognosis. Double-expressor DLBCL (c-myc+/bcl-2+) has intermediate prognosis when compared to HG-DLBCL. Primary central nervous system lymphoma (PCNSL) has distinct pathophysiology (frequent non-germinal center-like subtype and double-expressor) and has worse prognosis than systemic DLBCL. By fluorescence in situ hybridization (FISH), 25-30% of PCNSLs harbor BCL6 abnormalities with rare alterations in MYC, BCL2, double-hit or triple-hit events. We describe the clinicopathologic features and status of MYC, BCL2 and BCL6 in 12 PCNSLs (7 women, 5 men; median age 63 years; range: 28-79). Six cases showed focal starry-sky pattern. Immunohistochemically, all (100%) were of non-germinal center-like subtype, and 8/10 (80%) cases were double-expressors. Ki-67 ranged from 70 to 100%. FISH was positive in 9/12 (75%) cases: 4 (33%) harbored a BCL6 rearrangement, 3 (25%) had a gain of BCL2, 2 (17%) cases each had a gain of BCL6 and gain of IGH, and gain of MYC and deletion of MYC were observed in 1 case each (8%). Two (16%) cases were MYC/BCL6 double-hit PCNSLs. No MYC/BCL2 or triple-hit cases were identified. Eleven (92%) patients received chemotherapy and one also received whole brain radiation. The median time of follow-up was 4.4 months (range, 0.3-40.3). Seven (58%) patients are alive, 4 (33%) have died, and 1 (8%) had no follow-up. Five alive patients are in remission, including one MYC/BCL6 double-hit PCNSL. Our results add two new cases of rare double-hit PCNSL to the literature.

Activation-induced cytidine deaminase overexpression in double-hit lymphoma: potential target for novel anticancer therapy

Activation-induced cytidine deaminase (AID) is one kind of the mutant enzymes, which target regulating the immunoglobulin (Ig) gene in Burkitt's lymphoma to initiate class switch recombination (CSR), resulting in c-Myc chromosomal translocation. However, it is not clear that whether AID induces c-Myc/IgH translocation in double-hit lymphoma (DHL) with c-Myc gene translocation. In this study, the AID in DHL tissues and classical diffuse large b-cell lymphoma (DLBCL) tissues were compared. The results suggested that AID is of important value in predicting DHL, stronger CSR of AID was observed in DHL patients, which exhibited AID overexpression and c-Myc gene translocation of DHL after CSR induction. It is concluded that AID directly induces CSR in DHL and may result in c-Myc gene translocation. Targeting AID may be a good treatment regimen for DHL.

[Prognostic evaluation of P53 and BCL2 proteins in MYC/BCL2 double expression DLBCL]

Objective: To investigate the strong expression (S+) of P53 and BCL2 proteins in MYC/BCL2 double-expression DLBCL (DEL) and whether they can be used for the prognostic evaluation and stratified diagnosis of DELs. Methods: Tissue microarray were made by filed FFPE blocks of 174 DLBCL cases. The translocation of MYC, BCL2 and BCL6 genes were detected by FISH, and the proteins were detected by IHC. Data of clinicopathologic features and follow up of patients were collected and OS (overall survival) and PFS (progression free survival) were analyzed by statistics. Results: Eight double-hit lymphomas (DHLs) were identified in all cases, and 45 DELs were selected from 166 remaining cases, which have no significant difference in OS and PFS compared with non-DEL cases (P=0.668 and P=0.790) . Of 42 DEL-cases with follow up data, 24 cases with P53+ or/and BCL2 (S+) are significantly shorter OS and PFS than others (P=0.003 and P=0.000) , in which the cases with P53+/BCL2 (S+) co-expression were the worst prognosis, and P53/BCL2 co-weaker positive DEL cases even have superior OS and PFS than those non-DELs. Although statistics showed that the cases of P53+ or/and BCL2 (S+) have a lower OS and PFS in total cases (P=0.063 and P=0.024) , it is not the case when the DEL-cases take out from total cases, that is the cases with P53+ or/and BCL2 (S+) are as similar OS and PFS as others in non-DEL group (P=0.590 and P=0.550) . Conclusion: The strong expression of P53 and BCL2 proteins can be used as indicators of stratified diagnosis and poor prognosis of DEL.

A novel classification based on B-cell receptor signal gene expression correlates with prognosis in primary breast diffuse large B-cell lymphoma

Primary breast diffuse large B-cell lymphoma (PB-DLBCL), the most common histologic subtype of lymphoid malignancy in the breast, is a clinically and genetically heterogeneous disease that has insufficient systematic studies on the pathological and molecular features, optimal treatment scheme, as well as the prognostic factors. The aim of our study was to identify biomarkers and distinct subtypes of PB-DLBCLs and then evaluate the prognosis of this rare malignant lymphoma. We carried out hierarchical clustering analysis to evaluate protein expressions of potential biomarkers detected by immunohistochemistry staining of samples from 68 PB-DLBCL patients. The gene expression data from TCGA database was obtained to validate the identified clusters. We identified three robust clusters based on the B-cell receptor (BCR) signaling pathway, including two recognized NF-κB-dependent and PI3K-dependent clusters, and a distinct subset of PB-DLBCL with NF-κB-independent anti-apoptotic overexpression plus PI3K signaling, which exhibited an evolving definition and distinctive characters of a cluster group. Furthermore, survival analysis results showed an inferior outcome in NF-κB-dependent cluster patients and favorable survival in the PI3K-dependent cluster patients, suggesting an important predictive value of the three clusters. Our study provided a new perspective for understanding clinical complexity of PB-DLBCLs, and gave evidence for finding targeted biomarkers and strategies.

High-Grade B-Cell Lymphomas, Not Otherwise Specified: A Study of 41 Cases

Purpose

To analyze the clinical and pathological characteristics, treatment, and prognosis of high-grade B-cell lymphomas, not otherwise specified (HGBL, NOS), and to increase awareness of this type of lymphoma.

Patients and Methods

We collected clinical and pathological data of 41 cases of newly diagnosed HGBL, NOS, and analyzed diagnosis, prognosis and treatment to examine progression-free survival (PFS) and overall survival (OS).

Results

Among the 41 cases studied, the median PFS was 6.0 months and the median OS was 18.0 months. Compared with patients treated with the R-CHOP regimen, patients treated with a high-intensity chemotherapy (DA-EPOCH-R, R-CODOX-M/IVAC, or R-Hyper-CVAD) had superior PFS and OS (PFS: χ²=4.173, P=0.041; OS: χ²=5.200, P=0.023). A subgroup analysis showed that the OS for the double-expressor lymphoma (DEL) was inferior to that for the non-DEL (χ²=4.563, P=0.033), and this trend was also seen for the single-hit lymphoma with MYC rearrangement (SHL) and the non-SHL (χ²=4.955, P=0.026). Patients with low International Prognostic Index (IPI) scores (≤2) had better survival rates than those with high scores (>2) (PFS: χ²=6.482, P=0.011; OS: χ²=10.156, P=0.001).

Conclusion

HGBL, NOS is associated with a high degree of malignancy, short survival period, and substantial extranodal involvement. High-intensity chemotherapy may improve patient prognosis. While IPI scores statistically correlated with the prognosis, SHL and DEL correlated with an inferior survival rate. New and improved treatments will be needed for HGBL, NOS.

Advances in targeted therapy for malignant lymphoma

The incidence of lymphoma has gradually increased over previous decades, and it ranks among the ten most prevalent cancers worldwide. With the development of targeted therapeutic strategies, though a subset of lymphoma patients has become curable, the treatment of refractory and relapsed diseases remains challenging. Many efforts have been made to explore new targets and to develop corresponding therapies. In addition to novel antibodies targeting surface antigens and small molecular inhibitors targeting oncogenic signaling pathways and tumor suppressors, immune checkpoint inhibitors and chimeric antigen receptor T-cells have been rapidly developed to target the tumor microenvironment. Although these targeted agents have shown great success in treating lymphoma patients, adverse events should be noted. The selection of the most suitable candidates, optimal dosage, and effective combinations warrant further investigation. In this review, we systematically outlined the advances in targeted therapy for malignant lymphoma, providing a clinical rationale for mechanism-based lymphoma treatment in the era of precision medicine.

Educational Case: Gastric High-Grade B-Cell Lymphoma With MYC and BCL2 Gene Rearrangement (Double-Hit Lymphoma)

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

MYC in Germinal Center-derived lymphomas: Mechanisms and therapeutic opportunities

The rearrangement of immunoglobulin loci during the germinal center reaction is associated with an increased risk of chromosomal translocations that activate oncogenes such as MYC, BCL2 or BCL6, thus contributing to the development of B-cell lymphomas. MYC and BCL2 activation are initiating events in Burkitt's (BL) and Follicular Lymphoma (FL), respectively, but can occur at later stages in other subtypes such as Diffuse Large-B Cell Lymphoma (DLBCL). MYC can also be activated during the progression of FL to the transformed stage. Thus, either DLBCL or FL can give rise to aggressive double-hit lymphomas (DHL) with concurrent activation of MYC and BCL2. Research over the last three decades has improved our understanding of the functions of these oncogenes and the basis for their cooperative action in lymphomagenesis. MYC, in particular, is a transcription factor that contributes to cell activation, growth and proliferation, while concomitantly sensitizing cells to apoptosis, the latter being blocked by BCL2. Here, we review our current knowledge about the role of MYC in germinal center B-cells and lymphomas, discuss MYC-induced dependencies that can sensitize cancer cells to select pharmacological inhibitors, and illustrate their therapeutic potential in aggressive lymphomas-and in particular in DHL, in combination with BCL2 inhibitors.

Prohibitin (PHB) expression is associated with aggressiveness in DLBCL and flavagline-mediated inhibition of cytoplasmic PHB functions induces anti-tumor effects

BACKGROUND

Diffuse large B-cell lymphomas (DLBCLs) are aggressive lymphomas accounting for approximately a third of non-Hodgkin lymphomas. Prohibitin 1 (PHB1) and prohibitin 2 (PHB2) are scaffold proteins that promote mitochondria homeostasis and consequently cell survival, but biological functions of cytoplasmic PHBs remain largely unknown in DLBCL.

METHODS

PHB expression was analyzed in 82 DLBCL biopsies and five DLBCL cell lines by immunohistochemistry (IHC) and Western blotting. Pharmacological inhibition of PHB using the synthetic flavagline FL3 was realized in vitro to gain insight PHB cellular functions. Effects of FL3 on DLBCL cell line viability, apoptosis, C-Raf-ERK-MNK-eIF4E signaling pathway and eIF4F complex formation and activity were evaluated by XTT assay, annexin V-FITC/PI dual staining and Western blotting respectively. Subcutaneous DLBCL xenograft model in SCID mice was also performed to determine in vivo FL3 effect.

RESULTS

As in DLBCL cell lines, PHB1 and PHB2 were expressed in germinal center B-cell-like (GCB) and activated B-cell-like (ABC) subtypes. In patient samples, high PHB levels were associated with higher serum LDH (PHB1 and PHB2), IPIaa (PHB2), and Ki-67 (PHB2) expression. Higher PHB1 expression tends to be associated with shorter event-free survival (EFS) in patients, especially in male patients. FL3 induced apoptosis of DLBCL cell lines that was associated with inhibition of the ERK-MNK-eIF4E signaling pathway, including aggressive double/triple-hit DLBCL cell lines. This resulted in altered eIF4F complex formation and activity leading to a reduction of Bcl-2 and c-Myc expression levels. Moreover, FL3 strongly downregulated DLBCL cellular levels of Akt protein and AKT mRNA. FL3 antitumor activity was also confirmed in vivo in a murine xenograft model.

CONCLUSION

Our data indicate that PHB overexpression is associated with markers of tumor aggressiveness in DLBCL, and that targeting PHBs may be a therapeutic option, notably in aggressive subtypes.

Characteristics of CD5-positive diffuse large B-cell lymphoma among Koreans: High incidence of BCL2 and MYC double-expressors

Aberrant expression of CD5 has been reported in 5-10% of diffuse large B-cell lymphomas (DLBCLs). CD5+ DLBCL had been recognized as an aggressive immunophenotypic subgroup of DLBCL in the 2008 WHO classification of haematolymphoid neoplasm; however, it was eliminated from the list of subgroups of DLBCLs in the revised 2016 classification. Nevertheless, there is much controversy regarding the clinical significance of CD5 expression, and many researchers still assert that this subgroup exhibits an extremely unfavorable prognosis with frequent treatment failure. We retrospectively investigated 405 DLBCLs recruited from three university hospitals in Korea from 1997 to 2013. The clinical profile, immunophenotype, and chromosomal structural alterations of the BCL2 and MYC genes were compared according to CD5 expression. A total of 29 cases of de novo CD5+ DLBCL were identified out of 405 in our series (7.4%). Clinicopathologic correlation was performed in all 29 CD5+ DLBCLs and 166 CD5- DLBCLs which were eligible for full clinical review and further pathologic examination. Compared with CD5- counterparts, CD5+ DLBCLs showed female preponderance, frequent bone marrow involvement, higher lactate dehydrogenase level, advanced Ann Arbor stages and poorer prognosis (all p<0.05). Pathologically, the expression of CD5 positively correlated with that of BCL2, MYC and Ki-67 (all p<0.05). Coexpression of BCL2 and MYC, which is referred to as a double-expressor, was relatively more common in CD5+ DLBCL, whereas translocation or amplification of these genes was very rare. in conclusion, the expression of CD5 is an independent poor prognostic factor of DLBCLs, and this subgroup displays unique clinicopathologic features. Although the exact mechanism remains uncertain, consistent activation of BCL2 and MYC by alternative pathways other than chromosomal translocation may contribute to the pathogenesis.

A super-SILAC based proteomics analysis of diffuse large B-cell lymphoma-NOS patient samples to identify new proteins that discriminate GCB and non-GCB lymphomas

Diffuse large B-cell lymphoma—not otherwise specified (DLBCL-NOS) is a large and heterogeneous subgroup of non-Hodgkin lymphoma. DLBCL can be subdivided into germinal centre B-cell like (GCB) and activated B-cell like (ABC or non-GCB) using a gene-expression based or an immunohistochemical approach. In this study we aimed to identify additional proteins that are differentially expressed between GCB and non-GCB DLBCL. A reference super-SILAC mix, including proteins of eight B-cell lymphoma cell lines, was mixed with proteins isolated from seven non-GCB DLBCL and five GCB DLBCL patient tissue samples to quantify protein levels. Protein identification and quantification was performed by LC-MS. We identified a total of 4289 proteins, with a four-fold significant difference in expression between non-GCB and GCB DLBCL for 37 proteins. Four proteins were selected for validation in the same cases and replication in an independent cohort of 47 DLBCL patients by immunohistochemistry. In the validation cohort, we observed a non-significant trend towards the same differential expression pattern as observed in the proteomics. The replication study showed significant and consistent differences for two of the proteins: expression of glomulin (GLMN) was higher in GCB DLBCL, while expression of ribosomal protein L23 (RPL23) was higher in non-GCB DLBCL. These proteins are functionally linked to important pathways involving MYC, p53 and angiogenesis. In summary, we showed increased expression of RPL23 and decreased expression of GLMN in non-GCB compared to GCB DLBCL on purified primary DLBCL patient samples and replicated these results in an independent patient cohort.

Specific interactions of BCL-2 family proteins mediate sensitivity to BH3-mimetics in diffuse large B-cell lymphoma

The BCL-2-specific inhibitor, ABT-199 (venetoclax) has exhibited remarkable clinical activity in nearly all cases of chronic lymphocytic leukemia. In contrast, responses are usually much less in diffuse large B-cell lymphoma (DLBCL), despite high level expression of BCL-2 in over 40% of cases, indicating that co-expression of related anti-apoptotic BCL-2 family proteins may limit the activity of ABT-199. We have investigated the roles of BCL-2 proteins in DLBCL cells using a panel of specific BCL-2 homology 3 (BH3)-mimetics and identified subgroups of these cells that exhibited marked and specific dependency on either BCL-2, BCL-X_L or MCL-1 for survival. Dependency was associated with selective sequestration of the pro-apoptotic proteins BIM, BAX and BAK by the specific anti-apoptotic BCL-2 protein which was important for cellular survival. Sensitivity to BH3-mimetics was independent of genetic alterations involving the BCL-2 family and only partially correlated with protein expression levels. Treatment with ABT-199 displaced BAX and BIM from BCL-2, subsequently leading to BAK activation and apoptosis. In contrast, apoptosis induced by inhibiting BCL-X_L with A1331852 was associated with a displacement of both BAX and BAK from BCL-X_L and occurred independently of BIM. Finally, the MCL-1 inhibitor S63845 induced mainly BAX-dependent apoptosis mediated by a displacement of BAK, BIM and NOXA from MCL-1. In conclusion, our study indicates that in DLBCL, the heterogeneous response to BH3-mimetics is mediated by selective interactions between BAX, BAK and anti-apoptotic BCL-2 proteins.

Molecular Genetics in the Diagnosis and Biology of Lymphoid Neoplasms

OBJECTIVES

The 2017 Workshop of the Society for Hematopathology/European Association for Haematopathology reviewed the role of molecular genetics in the diagnosis and biology of lymphoid neoplasms.

METHODS

The Workshop Panel reviewed 82 cases.

RESULTS

Molecular genetic testing reveals alterations that expand the spectrum of diseases such as DUSP22 rearrangement in ALK-negative anaplastic large cell lymphoma, large B-cell lymphoma with IRF4 rearrangement, MYD88 mutations in B-cell lymphomas, Burkitt-like lymphoma with 11q aberrations, and diagnostic criteria for high-grade B-cell lymphomas. Therapeutic agents and natural tumor progression may be associated with transcriptional reprogramming that lead to transdifferentiation and lineage switch.

CONCLUSIONS

Application of emerging technical advances has revealed the complexity of genetic events in lymphomagenesis, progression, and acquired resistance to therapies. They also contribute to enhanced understanding of the biology of indolent vs aggressive behavior, clonal evolution, tumor progression, and transcriptional reprogramming associated with transdifferentiation events that may occur subsequent to therapy.