Understanding MYC-driven aggressive B-cell lymphomas: pathogenesis and classification

CD38 as theranostic target in oncology

CD38 is a multifunctional transmembrane glycoprotein found in multiple tissues and overexpressed in many cancer cells, notably in hematological malignancies such as leukemia and multiple myeloma (MM). Therefore, targeting CD38 remains an attractive strategy for cancer treatment in hematological malignancies as well as in solid tumors. It plays a critical role in the progression of these diseases through its ADP-ribosyl cyclase and cADPR-hydrolase activities. Its importance has led to the development of various anti-CD38 monoclonal antibodies (mAbs), including daratumumab and isatuximab, approved for MM treatment. These mAbs exert their anti-tumor effects through Fc-dependent immune mechanisms and immunomodulation, enhancing T-cell and NK-cell-mediated responses. However, resistance mechanisms arise during the treatment with daratumumab, creating the necessity for new therapies. This review explains current knowledge about the role of CD38 as a target in oncology and aims to delineate the use of single domain antibodies (sdAbs) as innovative theranostic tools in nuclear medicine. For diagnostic purposes, PET radionuclides like 68 Ga, 64Cu, and SPECT radionuclides like 99mTc and 111In, are commonly used. Significant progress has been made in anti-CD38 radioligand therapy (RLT), with anti-CD38 antibodies providing insights into tumor biology and treatment efficacy. In terms of therapy, RLT is a promising approach that offers precise targeting of malignant cells while minimizing exposure to healthy tissue. This involves the use of radionuclides emitting α particles, like 225Ac, 212Pb or 211At, and β--particles like 90Y, 131I, or 177Lu, to exert cytotoxic effects. Derived from Camelidae heavy chain antibodies, sdAbs offer advantages over conventional mAbs such as small size, high stability, specificity, and ability to recognize hidden epitopes. CD38-specific sdAbs, such as sdAb 2F8, characterized by our laboratory, showing excellent tumor targeting and their engineered constructs, such as biparatopic antibodies and chimeric antibodies, represent a new generation of theranostic agents for diagnosis and treatment CD38-expressing malignancies.

How lactate affects immune strategies in lymphoma

Tumor cells undergo metabolic reprogramming through shared pathways, resulting in a hypoxic, acidic, and highly permeable internal tumor microenvironment (TME). Lactate, once only regarded as a waste product of glycolysis, has an inseparable dual role with tumor immunity. It can not only provide a carbon source for immune cells to enhance immunity but also help the immune escape through a variety of ways. Lymphoma also depends on the proliferation signal of TME. This review focuses on the dynamic process of lactate metabolism and immune function changes in lymphoma and aims to comprehensively summarize and explore which genes, transcription factors, and pathways affect the biological changes and functions of immune cells. To deeply understand the complex and multifaceted role of lactate metabolism and immunity in lymphoma, the combination of lactate targeted therapy and classical immunotherapy will be a promising development direction in the future.

Histone Deacetylase Inhibitors for Peripheral T-Cell Lymphomas

Histone deacetylase inhibitors (HDACis) are being recognized as a potentially effective treatment approach for peripheral T-cell lymphomas (PTCLs), a heterogeneous group of aggressive malignancies with an unfavorable prognosis. Recent evidence has shown that HDACis are effective in treating PTCL, especially in cases where the disease has relapsed or is resistant to conventional treatments. Several clinical trials have demonstrated that HDACis, such as romidepsin and belinostat, can elicit long-lasting positive outcomes in individuals with PTCLs, either when used alone or in conjunction with conventional chemotherapy. They exert their anti-tumor effects by regulating gene expression through the inhibition of histone deacetylases, which leads to cell cycle arrest, induction of programmed cell death, and,the transformation of cancerous T cells, as demonstrated by gene expression profile studies. Importantly, besides clinical trials, real-world evidence indicated that the utilization of HDACis presents a significant and beneficial treatment choice for PTCLs. However, although HDACis showed potential effectiveness, they could not cure most patients. Therefore, new combinations with conventional drugs as well as new targeted agents are under investigation.

Spatially exploring RNA biology in archival formalin-fixed paraffin-embedded tissues

The capability to spatially explore RNA biology in formalin-fixed paraffin-embedded (FFPE) tissues holds transformative potential for histopathology research. Here, we present pathology-compatible deterministic barcoding in tissue (Patho-DBiT) by combining in situ polyadenylation and computational innovation for spatial whole transcriptome sequencing, tailored to probe the diverse RNA species in clinically archived FFPE samples. It permits spatial co-profiling of gene expression and RNA processing, unveiling region-specific splicing isoforms, and high-sensitivity transcriptomic mapping of clinical tumor FFPE tissues stored for 5 years. Furthermore, genome-wide single-nucleotide RNA variants can be captured to distinguish malignant subclones from non-malignant cells in human lymphomas. Patho-DBiT also maps microRNA regulatory networks and RNA splicing dynamics, decoding their roles in spatial tumorigenesis. Single-cell level Patho-DBiT dissects the spatiotemporal cellular dynamics driving tumor clonal architecture and progression. Patho-DBiT stands poised as a valuable platform to unravel rich RNA biology in FFPE tissues to aid in clinical pathology evaluation.

Plasmablastic lymphoma: 2024 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Plasmablastic lymphoma (PBL) is a rare CD20-negative aggressive lymphoma with a poor prognosis under standard treatment options. Though PBL is associated with human immunodeficiency virus infection and other immunosuppressed states, it can also affect immunocompetent individuals.

DIAGNOSIS

The diagnosis requires a high clinical suspicion and pathological confirmation. EBER expression and MYC gene rearrangements are frequently detected. The differential diagnosis includes EBV+ diffuse large B-cell lymphoma, extracavitary primary effusion lymphoma, ALK+ DLBCL, and HHV8+ large B-cell lymphoma, among others.

RISK STRATIFICATION

Age ≥60 years, advanced clinical stage, and high intermediate and high International Prognostic Index scores are associated with worse survival.

MANAGEMENT

Combination chemotherapy regimens, such as EPOCH, are recommended. The addition of bortezomib, lenalidomide, or daratumumab might improve outcomes. Including PBL patients and their participation in prospective clinical trials is warranted.

Motive and opportunity: MYC rearrangements in high-grade B-cell lymphoma with MYC and BCL2 rearrangements (an LLMPP study)

ABSTRACT

Rearrangements that place the oncogenes MYC, BCL2, or BCL6 adjacent to superenhancers are common in mature B-cell lymphomas. Lymphomas with diffuse large B-cell lymphoma (DLBCL) or high-grade morphology with both MYC and BCL2 rearrangements are classified as high-grade B-cell lymphoma with MYC and BCL2 rearrangements ("double hit"; HGBCL-DH-BCL2) and are associated with aggressive disease and poor outcomes. Although it is established that MYC rearrangements involving immunoglobulin (IG) loci are associated with inferior outcomes relative to those involving other non-IG superenhancers, the frequency of and mechanisms driving IG vs non-IG MYC rearrangements have not been elucidated. Here, we used custom targeted capture and/or whole-genome sequencing to characterize oncogene rearrangements across 883 mature B-cell lymphomas including Burkitt lymphoma, follicular lymphoma, DLBCL, and HGBCL-DH-BCL2 tumors. We demonstrate that, although BCL2 rearrangement topology is consistent across entities, HGBCL-DH-BCL2 have distinct MYC rearrangement architecture relative to tumors with single MYC rearrangements or with both MYC and BCL6 rearrangements (HGBCL-DH-BCL6), including both a higher frequency of non-IG rearrangements and different architecture of MYC::IGH rearrangements. The distinct MYC rearrangement patterns in HGBCL-DH-BCL2 occur on the background of high levels of somatic hypermutation across MYC partner loci in HGBCL-DH-BCL2, creating more opportunity to form these rearrangements. Furthermore, because 1 IGH allele is already disrupted by the existing BCL2 rearrangement, the MYC rearrangement architecture in HGBCL-DH-BCL2 likely reflects selective pressure to preserve both BCL2 and B-cell receptor expression. These data provide new mechanistic explanations for the distinct patterns of MYC rearrangements observed across different lymphoma entities.

Thinking Outside the Box: Indirect Myc Modulation in Canine B-Cell Lymphoma

B-cell lymphomas (BCL) is the most frequent hematological cancer in dogs. Treatment typically consists of chemotherapy, with CHOP-based protocols. However, outcome remains generally poor, urging the exploration of new therapeutic strategies with a targeted approach. Myc transcription factor plays a crucial role in regulating cellular processes, and its dysregulation is implicated in numerous human and canine malignancies, including canine BCL (cBCL). This study aims to evaluate the efficacy of indirectly inhibiting Myc in cBCL using BI2536 and MZ1 compounds in two in vitro models (CLBL-1 and KLR-1201). Both BI2536 and MZ1, alone and combined, affected cell viability in a significant concentration- and time-dependent manner. Western Blot revealed an upregulation of PLK1 expression in both cell lines upon treatment with BI2536, in association with a reduction in c-Myc protein levels. Conversely, MZ1 led to a decrease in its primary target, BRD4, along with a reduction in c-Myc. Furthermore, BI2536, both alone and in combination with MZ1, induced larger transcriptomic changes in cells compared to MZ1 alone, primarily affecting MYC target genes and genes involved in cell cycle regulation. These data underscore the potential role of Myc as therapeutic target in cBCL, providing a novel approach to indirectly modulate this molecule.

Ajania pacifica (Nakai) K. Bremer and Humphries Extract Limits MYC Expression to Induce Apoptosis in Diffuse Large B Cell Lymphoma

The proto-oncogene MYC is frequently dysregulated in patients with diffuse large B-cell lymphoma (DLBCL) and plays a critical role in disease progression. To improve the clinical outcomes of patients with DLBCL, the development of strategies to target MYC is crucial. The use of medicinal plants for developing anticancer drugs has garnered considerable attention owing to their diverse mechanisms of action. In this study, 100 plant extracts of flora from the Republic of Korea were screened to search for novel agents with anti-DLBCL effects. Among them, Ajania pacifica (Nakai) K. Bremer and Humphries extract (APKH) efficiently suppressed the survival of DLBCL cells, while showing minimal toxicity toward normal murine bone marrow cells. APKH suppressed the expression of anti-apoptotic BCL2 family members, causing an imbalance between the pro-apoptotic and anti-apoptotic BCL2 members. This disrupted mitochondrial membrane potential, cytochrome c release, and pro-caspase-3 activation and eventually led to DLBCL cell death. Importantly, MYC expression was markedly downregulated by APKH and ectopic expression of MYC in DLBCL cells abolished the pro-apoptotic effects of APKH. These results demonstrate that APKH exerts anti-DLBCL effects by inhibiting MYC expression. Moreover, when combined with doxorubicin, an essential component of the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisone), APKH synergistically enhanced the therapeutic effect of doxorubicin. This indicates that APKH may overcome drug resistance, which is common in patients with refractory/relapsed DLBCL. To identify compounds with anti-DLBCL activities in APKH, the chemical profile analysis of APKH was performed using UPLC-QTOF/MSe analysis and assessed for its anticancer activity. Based on the UPLC-QTOF/MSe chemical profiling, it is conceivable that APKH may serve as a novel agent targeting MYC and sensitizing drug-resistant DLBCL cells to CHOP chemotherapy. Further studies to elucidate how the compounds in APKH exert tumor-suppressive role in DLBCL are warranted.

Integrative genomic analysis identifies unique immune environments associated with immunotherapy response in diffuse large B cell lymphoma

Most diffuse large B-cell lymphoma (DLBCL) patients treated with bispecific antibodies (BsAb) or chimeric antigen receptor (CAR) T cells fail to achieve durable treatment responses, underscoring the need for a deeper understanding of mechanisms that regulate the immune environment and response to treatment. Here, an integrative, multi-omic approach was employed to characterize DLBCL immune environments, which effectively segregated DLBCLs into four quadrants - termed DLBCL-immune quadrants (IQ) - defined by cell-of-origin and immune-related gene set expression scores. Recurrent genomic alterations were enriched in each IQ, suggesting that lymphoma cell-intrinsic alterations contribute to orchestrating unique DLBCL immune environments. In relapsed/refractory DLBCL patients, DLBCL-IQ assignment correlated significantly with clinical benefit with the CD20 x CD3 BsAb, mosunetuzumab, but not with CD19-directed CAR T cells. DLBCL-IQ provides a new framework to conceptualize the DLBCL immune landscape and uncovers the differential impact of the endogenous immune environment on outcomes to BsAb and CAR T cell treatment.

The HSP90-MYC-CDK9 network drives therapeutic resistance in mantle cell lymphoma

Brexucabtagene autoleucel CAR-T therapy is highly efficacious in overcoming resistance to Bruton's tyrosine kinase inhibitors (BTKi) in mantle cell lymphoma. However, many patients relapse post CAR-T therapy with dismal outcomes. To dissect the underlying mechanisms of sequential resistance to BTKi and CAR-T therapy, we performed single-cell RNA sequencing analysis for 66 samples from 25 patients treated with BTKi and/or CAR-T therapy and conducted in-depth bioinformatics™ analysis. Our analysis revealed that MYC activity progressively increased with sequential resistance. HSP90AB1 (Heat shock protein 90 alpha family class B member 1), a MYC target, was identified as early driver of CAR-T resistance. CDK9 (Cyclin-dependent kinase 9), another MYC target, was significantly upregulated in Dual-R samples. Both HSP90AB1 and CDK9 expression were correlated with MYC activity levels. Pharmaceutical co-targeting of HSP90 and CDK9 synergistically diminished MYC activity, leading to potent anti-MCL activity. Collectively, our study revealed that HSP90-MYC-CDK9 network is the primary driving force of therapeutic resistance.

Antitumor efficacy of a sequence-specific DNA-targeted γPNA-based c-Myc inhibitor

Targeting oncogenes at the genomic DNA level can open new avenues for precision medicine. Significant efforts are ongoing to target oncogenes using RNA-targeted and protein-targeted platforms, but no progress has been made to target genomic DNA for cancer therapy. Here, we introduce a gamma peptide nucleic acid (γPNA)-based genomic DNA-targeted platform to silence oncogenes in vivo. γPNAs efficiently invade the mixed sequences of genomic DNA with high affinity and specificity. As a proof of concept, we establish that γPNA can inhibit c-Myc transcription in multiple cell lines. We evaluate the in vivo efficacy and safety of genomic DNA targeting in three pre-clinical models. We also establish that anti-transcription γPNA in combination with histone deacetylase inhibitors and chemotherapeutic drugs results in robust antitumor activity in cell-line- and patient-derived xenografts. Overall, this strategy offers a unique therapeutic platform to target genomic DNA to inhibit oncogenes for cancer therapy.

Multiple roles for AU-rich RNA binding proteins in the development of haematologic malignancies and their resistance to chemotherapy

Post-transcriptional regulation by RNA binding proteins can determine gene expression levels and drive changes in cancer cell proteomes. Identifying mechanisms of protein-RNA binding, including preferred sequence motifs bound in vivo, provides insights into protein-RNA networks and how they impact mRNA structure, function, and stability. In this review, we will focus on proteins that bind to AU-rich elements (AREs) in nascent or mature mRNA where they play roles in response to stresses encountered by cancer cells. ARE-binding proteins (ARE-BPs) specifically impact alternative splicing, stability, decay and translation, and formation of RNA-rich biomolecular condensates like cytoplasmic stress granules (SGs). For example, recent findings highlight the role of ARE-BPs - like TIAR and HUR - in chemotherapy resistance and in translational regulation of mRNAs encoding pro-inflammatory cytokines. We will discuss emerging evidence that different modes of ARE-BP activity impact leukaemia and lymphoma development, progression, adaptation to microenvironment and chemotherapy resistance.

MYC directly transactivates CR2/CD21, the receptor of the Epstein-Barr virus, enhancing the viral infection of Burkitt lymphoma cells

MYC is an oncogenic transcription factor dysregulated in about half of total human tumors. While transcriptomic studies reveal more than 1000 genes regulated by MYC, a much smaller fraction of genes is directly transactivated by MYC. Virtually all Burkitt lymphoma (BL) carry chromosomal translocations involving MYC oncogene. Most endemic BL and a fraction of sporadic BL are associated with Epstein-Barr virus (EBV) infection. The currently accepted mechanism is that EBV is the BL-causing agent inducing MYC translocation. Herein we show that the EBV receptor, CR2 (also called CD21), is a direct MYC target gene. This is based on several pieces of evidence: MYC induces CR2 expression in both proliferating and arrested cells and in the absence of protein synthesis, binds the CR2 promoter and transactivates CR2 in an E-box-dependent manner. Moreover, using mice with conditional MYC ablation we show that MYC induces CR2 in primary B cells. Importantly, modulation of MYC levels directly correlates with EBV's ability of infection in BL cells. Altogether, in contrast to the widely accepted hypothesis for the correlation between EBV and BL, we propose an alternative hypothesis in which MYC dysregulation could be the first event leading to the subsequent EBV infection.

Integrated Transcriptomics and Network Analysis of Potential Mechanisms and Health Effects of Convalescent COVID-19 Patients

Coronaviral disease 2019 (COVID-19) is a recent pandemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, there are still cases of COVID-19 around the world that can develop into persistent symptoms after discharge. The constellation of symptoms, termed long COVID, persists for months and can lead to various diseases such as lung inflammation and cardiovascular disease, which may lead to considerable financial burden and possible risk to human health. Moreover, the molecular mechanisms underlying the post-pandemic syndrome of COVID-19 remain unclear. In this study, we aimed to explore the molecular mechanism, disease association, and possible health risks in convalescent COVID-19 patients. Gene expression data from a human convalescent COVID-19 data set was compared with a data set from healthy normal individuals in order to identify differentially expressed genes (DEGs). To determine biological function and potential pathway alterations, the GO and KEGG databases were used to analyze the DEGs. Disease association, tissue, and organ-specific analyses were used to identify possible health effects. A total of 250 DEGs were identified between healthy and convalescent COVID-19 subjects. The biological function alterations identified revealed cytokine interactions and increased inflammation through NF-κB1, RELA, JUN, STAT3, and SP1. Interestingly, the most significant pathways were cytokine-cytokine receptor interaction, altered lipid metabolism, and atherosclerosis that play a crucial role in convalescent COVID-19. In addition, we also found pneumonitis, dermatitis, and autoimmune diseases. Based on our study, convalescent COVID-19 is associated with inflammation in a variety of organs that could lead to autoimmune and inflammatory diseases, as well as atherosclerosis. These findings are a first step toward fully exploring the disease mechanisms in depth to understand the relationship between post-COVID-19 infection and potential health risks. This is necessary for the development of appropriate strategies for the prevention and treatment of long COVID.

Analysis of endoplasmic reticulum stress-related gene signature for the prognosis and pattern in diffuse large B cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults. This study aimed to determine the prognostic significance of endoplasmic reticulum (ER) stress-related genes in DLBCL. ER stress-related genes were obtained from the molecular signatures database. Gene expression data and clinical outcomes from the gene expression omnibus and TCGA datasets were collected, and differentially expressed genes (DEGs) were screened out. Gene ontology enrichment analysis, the kyoto encyclopaedia of genes and genomes pathway analysis, and geneset enrichment analysis were used to analyse the possible biological function of ER stress-related DEGs in DLBCL. Protein-protein interaction network construction using the STRING online and hub genes were identified by cytoHubba on Cytoscape software. The significant prognosis-related genes were screened, and the differential expression was validated. The immune microenvironment assessment of significant genes were evaluated. Next, the nomogram was built using univariate and multivariate Cox regression analysis. 26 ER stress-related DEGs were screened. Functional enrichment analysis showed them to be involved in the regulation of the endoplasmic reticulum mainly. NUPR1 and TRIB3 were identified as the most significant prognostic-related genes by comparison with the GSE10846, GSE11318, and TCGA datasets. NUPR1 was correlated with a good prognosis and immune infiltration in DLBCL; on the other hand, high expression of TRIB3 significantly correlated with a poor prognosis, which was an independent prognostic factor for DLBCL. In summary, we identified NUPR1 and TRIB3 as critical ER stress-related genes in DLBCL. NUPR1 might be involved in immune infiltration in DLBCL, and TRIB3 might serve as a potential therapeutic target and prognostic factor in DLBCL.

Dynamic mitochondrial transcription and translation in B cells control germinal center entry and lymphomagenesis

Germinal center (GC) B cells undergo proliferation at very high rates in a hypoxic microenvironment but the cellular processes driving this are incompletely understood. Here we show that the mitochondria of GC B cells are highly dynamic, with significantly upregulated transcription and translation rates associated with the activity of transcription factor A, mitochondrial (TFAM). TFAM, while also necessary for normal B cell development, is required for entry of activated GC precursor B cells into the germinal center reaction; deletion of Tfam significantly impairs GC formation, function and output. Loss of TFAM in B cells compromises the actin cytoskeleton and impairs cellular motility of GC B cells in response to chemokine signaling, leading to their spatial disorganization. We show that B cell lymphoma substantially increases mitochondrial translation and that deletion of Tfam in B cells is protective against the development of lymphoma in a c-Myc transgenic mouse model. Finally, we show that pharmacological inhibition of mitochondrial transcription and translation inhibits growth of GC-derived human lymphoma cells and induces similar defects in the actin cytoskeleton.

Oncogenic roles and related mechanisms of the long non-coding RNA MINCR in human cancers

Long non-coding RNAs (lncRNAs) play vital roles in regulating epigenetic mechanisms and gene expression levels, and their dysregulation is closely associated with a variety of diseases such as cancer. Several studies have demonstrated that lncRNAs are dysregulated during tumor progression. Recently, the MYC-induced long non-coding RNA MINCR, a newly identified lncRNA, has been demonstrated to act as an oncogene in different cancers, including gallbladder cancer, hepatocellular cancer, colorectal cancer, non-small cell lung cancer, oral squamous cell carcinoma, nasopharyngeal cancer, and glioma. Moreover, MINCR has been reported to act as a biomarker in the prognosis of patients with different cancers. In this review, we summarize and analyze the oncogenic roles of MINCR in a variety of human cancers in terms of its clinical significance, biological functions, cellular activities, and regulatory mechanism. Our analysis of the literature suggests that MINCR has potential as a novel biomarker and therapeutic target in human cancers.

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.

Targeting MYC-driven lymphoma: lessons learned and future directions

MYC plays a central role in tumorigenesis by orchestrating cell proliferation, growth and survival, among other transformation mechanisms. In particular, MYC has often been associated with lymphomagenesis. In fact, MYC overexpressing lymphomas such as high-grade B-cell lymphoma (HGBL) and double expressor diffuse large B-cell lymphomas (DLBCL), are considered addicted to MYC. In such a context, MYC targeting therapies are of special interest, as MYC withdrawal is expected to result in tumor regression. However, whether high MYC levels are always predictive of increased sensitivity to these approaches is not clear yet. Even though no MYC inhibitor has received regulatory approval to date, substantial efforts have been made to investigate avenues to render MYC a druggable target. Here, we summarize the different classes of molecules currently under development, which mostly target MYC indirectly in aggressive B-cell lymphomas, paying special attention to subtypes with MYC/BCL2 or BCL6 translocations or overexpression.

Metabolic Reprogramming and Potential Therapeutic Targets in Lymphoma

Lymphoma is a heterogeneous group of diseases that often require their metabolism program to fulfill the demand of cell proliferation. Features of metabolism in lymphoma cells include high glucose uptake, deregulated expression of enzymes related to glycolysis, dual capacity for glycolytic and oxidative metabolism, elevated glutamine metabolism, and fatty acid synthesis. These aberrant metabolic changes lead to tumorigenesis, disease progression, and resistance to lymphoma chemotherapy. This metabolic reprogramming, including glucose, nucleic acid, fatty acid, and amino acid metabolism, is a dynamic process caused not only by genetic and epigenetic changes, but also by changes in the microenvironment affected by viral infections. Notably, some critical metabolic enzymes and metabolites may play vital roles in lymphomagenesis and progression. Recent studies have uncovered that metabolic pathways might have clinical impacts on the diagnosis, characterization, and treatment of lymphoma subtypes. However, determining the clinical relevance of biomarkers and therapeutic targets related to lymphoma metabolism is still challenging. In this review, we systematically summarize current studies on metabolism reprogramming in lymphoma, and we mainly focus on disorders of glucose, amino acids, and lipid metabolisms, as well as dysregulation of molecules in metabolic pathways, oncometabolites, and potential metabolic biomarkers. We then discuss strategies directly or indirectly for those potential therapeutic targets. Finally, we prospect the future directions of lymphoma treatment on metabolic reprogramming.

Molecular characterization and clinical outcome of B-cell precursor acute lymphoblastic leukemia with IG-MYC rearrangement

Rarely, immunophenotypically immature B-cell precursor acute lymphoblastic leukemia (BCP-ALL) carries an immunoglobulin- MYC rearrangement (IG-MYC-r). This can result in diagnostic confusion with Burkitt lymphoma/leukemia and use of individualized treatment schedules of unproven efficacy. Here we compare the molecular characteristics of these conditions and investigate historic clinical outcome data. We identified 90 cases registered in a national BCP-ALL clinical trial/registry. When present, diagnostic material underwent cytogenetic, exome, methylome and transcriptome analyses. The outcomes analyzed were 3-year event-free survival and overall survival. IG-MYC-r was identified in diverse cytogenetic backgrounds, co-existing with either established BCP-ALL-specific abnormalities (high hyperdiploidy, n=3; KMT2A-rearrangement, n=6; iAMP21, n=1; BCR-ABL1, n=1); BCL2/BCL6-rearrangements (n=15); or, most commonly, as the only defining feature (n=64). Within this final group, precursor-like V(D)J breakpoints predominated (8/9) and KRAS mutations were common (5/11). DNA methylation identified a cluster of V(D)J-rearranged cases, clearly distinct from Burkitt leukemia/lymphoma. Children with IG-MYC-r within that subgroup had a 3-year event-free survival of 47% and overall survival of 60%, representing a high-risk BCP-ALL. To develop effective management strategies this group of patients must be allowed access to contemporary, minimal residual disease-adapted, prospective clinical trial protocols.

Targeting positive cofactor 4 induces autophagic cell death in MYC-expressing diffuse large B-cell lymphoma

MYC-expressing diffuse large B-cell lymphoma (DLBCL) is one of the refractory lymphomas. Currently, the pathogenesis of MYC-expressing DLBCL is still unclear, and there is a lack of effective therapy. We characterized positive cofactor 4 (PC4) as an upstream regulator of c-Myc, and PC4 is overexpressed in DLBCL and is closely related to clinical staging, prognosis, and c-Myc expression. Furthermore, our in vivo and in vitro studies revealed that PC4 knockdown can induce autophagic cell death and enhance the therapeutic effect of doxorubicin in MYC-expressing DLBCL. Inhibition of c-Myc-mediated aerobic glycolysis and activation of the AMPK/mTOR signaling pathway are responsible for the autophagic cell death induced by PC4 knockdown in MYC-expressing DLBCL. Using dual-luciferase reporter assay and electrophoretic mobility shift assay assays, we also found that PC4 exerts its oncogenic functions by directly binding to c-Myc promoters. To sum up, our study provides novel insights into the functions and mechanisms of PC4 in MYC-expressing DLBCL and suggests that PC4 may be a promising therapeutic target for MYC-expressing DLBCL.

Strategies to target the cancer driver MYC in tumor cells

The MYC oncoprotein functions as a master regulator of cellular transcription and executes non-transcriptional tasks relevant to DNA replication and cell cycle regulation, thereby interacting with multiple proteins. MYC is required for fundamental cellular processes triggering proliferation, growth, differentiation, or apoptosis and also represents a major cancer driver being aberrantly activated in most human tumors. Due to its non-enzymatic biochemical functions and largely unstructured surface, MYC has remained difficult for specific inhibitor compounds to directly address, and consequently, alternative approaches leading to indirect MYC inhibition have evolved. Nowadays, multiple organic compounds, nucleic acids, or peptides specifically interfering with MYC activities are in preclinical or early-stage clinical studies, but none of them have been approved so far for the pharmacological treatment of cancer patients. In addition, specific and efficient delivery technologies to deliver MYC-inhibiting agents into MYC-dependent tumor cells are just beginning to emerge. In this review, an overview of direct and indirect MYC-inhibiting agents and their modes of MYC inhibition is given. Furthermore, we summarize current possibilities to deliver appropriate drugs into cancer cells containing derailed MYC using viral vectors or appropriate nanoparticles. Finding the right formulation to target MYC-dependent cancers and to achieve a high intracellular concentration of compounds blocking or attenuating oncogenic MYC activities could be as important as the development of novel MYC-inhibiting principles.

Genetic and phenotypic characterisation of HIV-associated aggressive B-cell non-Hodgkin lymphomas, which do not occur specifically in this population: diagnostic and prognostic implications

The frequency of aggressive subtypes of B-cell non-Hodgkin lymphoma (B-NHL), such as high-grade B-cell lymphomas (HGBL) with MYC and BCL2 and/or BCL6 rearrangement (HGBL-DH/TH) or Burkitt-like lymphoma (BL) with 11q aberration, is not well known in the HIV setting. We aimed to characterise HIV-associated aggressive B-NHL according to the 2017 WHO criteria, and to identify genotypic and phenotypic features with prognostic impact. Seventy-five HIV-associated aggressive B-NHL were studied by immunohistochemistry (CD10, BCL2, BCL6, MUM1, MYC, and CD30), EBV-encoded RNAs (EBERs), and fluorescence in situ hybridisation (FISH) to evaluate the status of the MYC, BCL2, and BCL6 genes and chromosome 11q. The 2017 WHO classification criteria and the Hans algorithm, for the cell-of-origin classification of diffuse large B-cell lymphomas (DLBCL), were applied. In DLBCL cases, the frequencies of MYC and BCL6 rearrangements (14.9 and 27.7%, respectively) were similar to those described in HIV-negative patients, but BCL2 rearrangements were infrequent (4.3%). MYC expression was identified in 23.4% of DLBCL cases, and coexpression of MYC and BCL2 in 13.0%, which was associated with a worse prognosis. As for BL cases, the expression of MUM1 (30.4%) conferred a worse prognosis. Finally, the prevalence of HGBL-DH/TH and BL-like with 11q aberration are reported in the HIV setting. The phenotypic and genotypic characteristics of HIV-associated aggressive B-NHL are similar to those of the general population, except for the low frequency of BCL2 rearrangements in DLBCL. MYC and BCL2 coexpression in DLBCL, and MUM-1 expression in BL, have a negative prognostic impact on HIV-infected individuals.

A polyamine-centric, blood-based metabolite panel predictive of poor response to CAR-T cell therapy in large B cell lymphoma

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy for relapsed or refractory (r/r) large B cell lymphoma (LBCL) results in durable response in only a subset of patients. MYC overexpression in LBCL tumors is associated with poor response to treatment. We tested whether an MYC-driven polyamine signature, as a liquid biopsy, is predictive of response to anti-CD19 CAR-T therapy in patients with r/r LBCL. Elevated plasma acetylated polyamines were associated with non-durable response. Concordantly, increased expression of spermidine synthase, a key enzyme that regulates levels of acetylated spermidine, was prognostic for survival in r/r LBCL. A broad metabolite screen identified additional markers that resulted in a 6-marker panel (6MetP) consisting of acetylspermidine, diacetylspermidine, and lysophospholipids, which was validated in an independent set from another institution as predictive of non-durable response to CAR-T therapy. A polyamine centric metabolomics liquid biopsy panel has predictive value for response to CAR-T therapy in r/r LBCL.

Advances in Understanding of Metabolism of B-Cell Lymphoma: Implications for Therapy

There have been significant recent advances in the understanding of the role of metabolism in normal and malignant B-cell biology. Previous research has focused on the role of MYC and mammalian target of rapamycin (mTOR) and how these interact with B-cell receptor signaling and hypoxia to regulate glycolysis, glutaminolysis, oxidative phosphorylation (OXPHOS) and related metabolic pathways in germinal centers. Many of the commonest forms of lymphoma arise from germinal center B-cells, reflecting the physiological attenuation of normal DNA damage checkpoints to facilitate somatic hypermutation of the immunoglobulin genes. As a result, these lymphomas can inherit the metabolic state of their cell-of-origin. There is increasing interest in the potential of targeting metabolic pathways for anti-cancer therapy. Some metabolic inhibitors such as methotrexate have been used to treat lymphoma for decades, with several new agents being recently licensed such as inhibitors of phosphoinositide-3-kinase. Several other inhibitors are in development including those blocking mTOR, glutaminase, OXPHOS and monocarboxylate transporters. In addition, recent work has highlighted the importance of the interaction between diet and cancer, with particular focus on dietary modifications that restrict carbohydrates and specific amino acids. This article will review the current state of this field and discuss future developments.

Clinical Application of Biomarkers for Hematologic Malignancies

Over the last decade, significant advancements have been made in the molecular mechanisms, diagnostic methods, prognostication, and treatment options in hematologic malignancies. As the treatment landscape continues to expand, personalized treatment is much more important.

With the development of new technologies, more sensitive evaluation of residual disease using flow cytometry and next generation sequencing is possible nowadays. Although some conventional biomarkers preserve their significance, novel potential biomarkers accurately detect the mutational landscape of different cancers, and also, serve as prognostic and predictive biomarkers, which can be used in evaluating therapy responses and relapses. It is likely that we will be able to offer a more targeted and risk-adapted therapeutic approach to patients with hematologic malignancies guided by these potential biomarkers. This chapter summarizes the biomarkers used (or proposed to be used) in the diagnosis and/or monitoring of hematologic neoplasms.;

Concomitant Inhibition of IRE1α/XBP1 Axis of UPR and PARP: A Promising Therapeutic Approach against c-Myc and Gammaherpesvirus-Driven B-Cell Lymphomas

It is emerging that targeting the adaptive functions of Unfolded Protein Response (UPR) may represent a promising anti-cancer therapeutic approach. This is particularly relevant for B-cell lymphomas, characterized by a high level of constitutive stress due to high c-Myc expression. In this study, we found that IRE1α/XBP1 axis inhibition exerted a stronger cytotoxic effect compared to the inhibition of the other two UPR sensors, namely PERK and ATF6, in Burkitt lymphoma (BL) cells, in correlation with c-Myc downregulation. Interestingly, such an effect was more evident in Epstein-Barr virus (EBV)-negative BL cells or those cells expressing type I latency compared to type III latency BL cells. The other interesting finding of this study was that the inhibition of IRE1α/XBP1 downregulated BRCA-1 and RAD51 and potentiated the cytotoxicity of PARP inhibitor AZD2661 against BL cells and also against Primary Effusion Lymphoma (PEL), another aggressive B-cell lymphoma driven by c-Myc and associated with gammaherpesvirus infection. These results suggest that combining the inhibition of UPR sensors, particularly IRE1α/XBP1 axis, and molecules involved in DDR, such as PARP, could offer a new therapeutic opportunity for treating aggressive B-cell lymphomas such as BL and PEL.

Simultaneous Analysis of the p16 Gene and Protein in Canine Lymphoma Cells and Their Correlation with pRb Phosphorylation

Simple Summary

Lymphoma is one of the most frequently diagnosed malignancies in dogs. The most common epigenetic alteration is gene methylation. Methylation of the p16 gene leads to decreased expression of its protein. The p16 protein inhibits the activity of cyclin-dependent kinase, as a negative control of the cell cycle to prevent phosphorylation of the retinoblastoma (pRb) protein. The methylation of the p16 gene has been reported in canine lymphomas, however, p16 protein expression has not been examined in previous studies. In this study, the gene and protein expression of p16, and phosphorylation of pRb, were examined simultaneously in canine lymphoma/leukemia cell lines treated with or without a demethylation drug in vitro. We identified the hypermethylation of the p16 gene, the decreased expression of p16 protein and the hyperphosphorylation of pRb in four out of eight cell lines. Furthermore, we revealed that the expression of the p16 protein was more stable than that of the p16 gene and more closely related to the phosphorylation of pRb. In conclusion, the p16 protein expression is suggested as a promising biomarker for canine lymphoma cells, and the p16–pRb pathway could be a target for the better treatment of canine lymphomas.

Abstract

Cyclin-dependent kinase inhibitor p16 (CDKN2A) primarily functions as a negative regulator of the retinoblastoma protein (pRb) pathway to prevent pRb phosphorylation, thus playing a critical role in cell cycle arrest. In canine lymphoma cells, methylation due to inactivation of the p16 gene has been reported. However, its protein expression has not been examined in previous studies. In our in vitro study, the gene and protein expression of p16 and phosphorylated pRb were examined simultaneously in eight canine lymphoma and leukemia cell lines (17-71, CLBL-1, GL-1, CLC, CLGL-90, Ema, Nody-1, and UL-1). Methylation of the p16 gene was also explored using the demethylation drug 5-Aza-2′-deoxycytidine (5-Aza). After 5-Aza treatment, p16 gene and protein expression increased and pRb phosphorylation decreased, suggesting that both hypermethylation of the p16 gene and pRb hyperphosphorylation occurred in four out of eight cell lines (CLBL-1, CLC, Nody-1, and UL-1). Moreover, the estimation of p16’s protein expression was better than that of p16’s mRNA expression because the expression of the protein was more stable than those of the gene, and highly related to the phosphorylation of pRb. These results revealed that p16’s protein expression could be a promising biomarker for canine lymphoma cells.

Clinical Features and Immunophenotypes of Double-Hit Diffuse Large B-Cell Lymphoma

Double-hit (DH) genetics induces a reduction in the complete remission (CR) and, consequently, in poor overall survival (OS) in diffuse large B-cell lymphoma (DLBCL) patients. Unfortunately, DH identification is time-consuming. Here, we retrospectively reviewed 92 newly diagnosed DLBCL patients, stratified them into the DH (n = 14) and non-DH groups (n = 78), and compared their clinical features and outcomes. The results revealed that the DH group had a higher percentage of bulky disease than the non-DH group (64.3% vs. 28.2%; p = 0.013). More patients in the DH group tested positive for double expresser (DE) (50.0% vs. 21.8%; p = 0.044). The three-year OS rates of patients with and without DH were 33.3% and 52.2%, respectively (p = 0.016). Importantly, advance stage and multiple comorbidities were correlated with a high mortality rate in multivariate analysis. Furthermore, by combining DE and the bulky disease, a specificity of 89.7% for DH prediction was achieved. In summary, DH genetics, not DE immunopositivity, could be a factor for an inferior OS in DLBCL. A combination of bulky disease and a positive DE immunophenotype could facilitate DH genetics prediction in newly diagnosed DLBCL patients.

BCL2 super-expressor diffuse large B-cell lymphoma: a distinct subgroup associated with poor prognosis

Overexpression of the BCL2 protein has been reported as a poor prognostic factor for diffuse large B-cell lymphoma (DLBCL). However, there are currently no standardized criteria for evaluating BCL2 protein expression. We aimed to evaluate the prognostic value of BCL2 expression determined by immunohistochemistry (IHC), incorporating both the staining intensity and proportion, in patients with de novo DLBCL who received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) as first-line treatment. We defined tumors with BCL2 expression in nearly all tumor cells with a uniformly strong intensity by IHC as BCL2 super-expressor. The BCL2 super-expressors (n = 35) showed significantly worse event-free survival (EFS; HR, 1.903; 95% CI, 1.159-3.126, P = 0.011) and overall survival (OS; HR, 2.467; 95% CI, 1.474-4.127, P = 0.001) compared with the non-BCL2 super-expressors (n = 234) independent of the international prognostic index (IPI), cell of origin (COO), and double expressor status in the training set (n = 269). The adverse prognostic impact of BCL2 super-expression was confirmed in the validation set (n = 195). When the survival outcomes were evaluated in the entire cohort (n = 464), BCL2 super-expressor group was significantly associated with inferior EFS and OS regardless of IPI, COO, MYC expression, and stages. BCL2 super-expressors had genetic aberrations enriched in the NOTCH and TP53 signaling pathways. This study suggests that the BCL2 super-expressor characterizes a distinct subset of DLBCL with a poor prognosis and warrants further investigation as a target population for BCL-2 inhibitors.

A bitesize introduction to canine hematologic malignancies

Hematologic malignancies are frequently diagnosed in dogs and result in a spectrum of clinical signs associated with specific disease types. The most frequently encountered hematologic tumors in dogs include lymphoma, lymphoid and myeloid leukemias, and mast cell, plasma cell, and histiocytic neoplasias. Coupled with the heterogeneous presentations of the different categories and subtypes of canine hematologic malignancies, outcomes for these tumors are also variable. Considering this, appropriate treatment options range from active surveillance to curative intent approaches harnessing surgical, chemotherapeutic, and radiation-based modalities. The underlying pathology of many of these diseases bears remarkable resemblance to that of the corresponding diagnosis made in human patients. We introduce some of the pathogenic drivers of canine hematologic cancers alongside their clinical presentations. An overview of standard-of-care therapies for each of these diseases is also provided. As comparative oncology gains recognition as a valuable setting in which to investigate the pathogenesis of neoplasia and provide powerful, clinically relevant, immunocompetent models for the evaluation of novel therapies, the number of clinicians and scientists participating in cancer research involving dogs is expected to increase. This review aims at providing an introductory overview of canine hematologic malignancies.

Pharmacodynamics and molecular correlates of response to glofitamab in relapsed/refractory non-Hodgkin lymphoma

Glofitamab, a novel CD20xCD3, T-cell-engaging bispecific antibody, exhibited single-agent activity in Study NP30179, a first-in-human, phase 1 trial in relapsed/refractory B-cell non-Hodgkin lymphoma. Preclinical studies showed that glofitamab leads to T-cell activation, proliferation, and tumor cell killing upon binding to CD20 on malignant cells. Here, we provide evidence of glofitamab's clinical activity, including pharmacodynamic profile, mode of action, and factors associated with clinical response, by evaluating biomarkers in patient samples from the dose-escalation part of this trial. Patients enrolled in Study NP30179 received single-dose obinutuzumab pretreatment (1000 mg) 7 days before IV glofitamab (5 µg-25 mg). Glofitamab treatment lasted ≤12 cycles once every 2 or 3 weeks. Blood samples were collected at predefined time points per the clinical protocol; T-cell populations were evaluated centrally by flow cytometry, and cytokine profiles were analyzed. Immunohistochemical and genomic biomarker analyses were performed on tumor biopsy samples. Pharmacodynamic modulation was observed with glofitamab treatment, including dose-dependent induction of cytokines, and T-cell margination, proliferation, and activation in peripheral blood. Gene expression analysis of pretreatment tumor biopsy samples indicated that tumor cell intrinsic factors such as TP53 signaling are associated with resistance to glofitamab, but they may also be interlinked with a diminished effector T-cell profile in resistant tumors and thus represent a poor prognostic factor per se. This integrative biomarker data analysis provides clinical evidence regarding glofitamab's mode of action, supports optimal biological dose selection, and will further guide clinical development. This trial was registered at www.clinicaltrials.gov as #NCT03075696.

Differential Transcriptional Reprogramming by Wild Type and Lymphoma-Associated Mutant MYC Proteins as B-Cells Convert to a Lymphoma Phenotype

The MYC transcription factor regulates a vast number of genes and is implicated in many human malignancies. In some hematological malignancies, MYC is frequently subject to missense mutations that enhance its transformation activity. Here, we use a novel murine cell system to (i) characterize the transcriptional effects of progressively increasing MYC levels as normal primary B-cells transform to lymphoma cells and (ii) determine how this gene regulation program is modified by lymphoma-associated MYC mutations (T58A and T58I) that enhance its transformation activity. Unlike many previous studies, the cell system exploits primary B-cells that are transduced to allow regulated MYC expression under circumstances where apoptosis and senescence pathways are abrogated by the over-expression of the Bcl-xL and BMI1 proteins. In such cells, transition from a normal to a lymphoma phenotype is directly dependent on the MYC expression level, without a requirement for secondary events that are normally required during MYC-driven oncogenic transformation. A generalized linear model approach allowed an integrated analysis of RNA sequencing data to identify regulated genes in relation to both progressively increasing MYC level and wild type or mutant status. Using this design, a total of 7569 regulated genes were identified, of which the majority (n = 7263) were regulated in response to progressively increased levels of wild type MYC, while a smaller number of genes (n = 917) were differentially regulated, compared to wild type MYC, in T58A MYC- and/or T58I MYC-expressing cells. Unlike most genes that are similarly regulated by both wild type and mutant MYC genes, the set of 917 genes did not significantly overlap with known lipopolysaccharide regulated genes, which represent genes regulated by MYC in normal B cells. The genes that were differently regulated in cells expressing mutant MYC proteins were significantly enriched in DNA replication and G2 phase to mitosis transition genes. Thus, mutants affecting MYC proteins may augment quantitative oncogenic effects on the expression of normal MYC-target genes with qualitative oncogenic effects, by which sets of cell cycle genes are abnormally targeted by MYC as B cells transition into lymphoma cells. The T58A and T58I mutations augment MYC-driven transformation by distinct mechanisms.

Advances in Lymphoma Molecular Diagnostics

Lymphomas encompass a diverse group of malignant lymphoid neoplasms. Over recent years much scientific effort has been undertaken to identify and understand molecular changes in lymphomas, resulting in a wide range of genetic alterations that have been reported across all types of lymphomas. As many of these changes are now incorporated into the World Health Organization’s defined criteria for the diagnostic evaluation of patients with lymphoid neoplasms, their accurate identification is crucial. Even if many alterations are not routinely evaluated in daily clinical practice, they may still have implications in risk stratification, treatment, prognosis or disease monitoring. Moreover, some alterations can be used for targeted treatment. Therefore, these advances in lymphoma molecular diagnostics in some cases have led to changes in treatment algorithms. Here, we give an overview of and discuss advances in molecular techniques in current clinical practice, as well as highlight some of them in a clinical context.

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.

Coexisting and Second Primary Cancers in Patients with Uveal Melanoma: A 10-Year Nationwide Database Analysis

Uveal melanoma is the most common intraocular tumor in adults. Metastatic disease occurs in about 30% of patients, for which there is currently no effective treatment. More than half of patients are long-term survivors, and it is well established that cancer survivors are prone to developing second primary cancers. In this study, we analyzed 10 years’ worth of data from the nationwide database to determine the rates of coexisting malignancies and second primary cancers associated with uveal melanoma. The mean annual incidence of uveal melanoma was 1.1 per million. Approximately 43% of patients had coexisting cancers. The most common coexisting cancer was lung cancer (10%) followed by liver cancer (6%) and non-Hodgkin lymphoma (6%). In patients whose first cancer in their lifetime was uveal melanoma, the 10-year cumulative incidence of second primary cancers was 22% (95% confidence interval, 9–31%). The age- and sex-adjusted standard incidence rates was 3.61 (95% confidence interval, 2.61–4.86). The most common second primary cancers were lung cancer and hepatocellular carcinoma, followed by prostate, thyroid, pancreatic, and ovarian cancers. Age was the only factor associated with second primary cancer development. Our findings will be helpful in providing counseling for cancer screening in uveal melanoma patients.

Human CD22-Transgenic, Primary Murine Lymphoma Challenges Immunotherapies in Organ-Specific Tumor Microenvironments

Targeted immunotherapies have greatly changed treatment of patients with B cell malignancies. To further enhance immunotherapies, research increasingly focuses on the tumor microenvironment (TME), which differs considerably by organ site. However, immunocompetent mouse models of disease to study immunotherapies targeting human molecules within organ-specific TME are surprisingly rare. We developed a myc-driven, primary murine lymphoma model expressing a human-mouse chimeric CD22 (h/mCD22). Stable engraftment of three distinct h/mCD22⁺ lymphoma was established after subcutaneous and systemic injection. However, only systemic lymphoma showed immune infiltration that reflected human disease. In this model, myeloid cells supported lymphoma growth and showed a phenotype of myeloid-derived suppressor cells. The human CD22-targeted immunotoxin Moxetumomab was highly active against h/mCD22⁺ lymphoma and similarly reduced infiltration of bone marrow and spleen of all three models up to 90-fold while efficacy against lymphoma in lymph nodes varied substantially, highlighting relevance of organ-specific TME. As in human aggressive lymphoma, anti-PD-L1 as monotherapy was not efficient. However, anti-PD-L1 enhanced efficacy of Moxetumomab suggesting potential for future clinical application. The novel model system of h/mCD22⁺ lymphoma provides a unique platform to test targeted immunotherapies and may be amenable for other human B cell targets such as CD19 and CD20.

Impact of Cell of Origin on Outcomes After Autologous Hematopoietic Cell Transplant in Diffuse Large B-Cell Lymphoma

Germinal center B-cell-like diffuse large B cell lymphoma (GCB-DLBCL) at diagnosis is associated with superior long-term outcomes compared to non-GCB-DLBCL in patients treated with conventional chemo-immunotherapy. Whether cell of origin (COO) by Hans algorithm retains its prognostic significance in patients with (R/R) relapsed/refractory DLBCL undergoing autologous hematopoietic cell transplant (auto-HCT) is not well established. Three hundred and fifty-seven patients underwent auto-HCT between 2005 and 2018. The COO status was determined in 284 patients and these were included in the analysis. One hundred ninety-four patients had GCB-DLBCL while 90 had non-GCB-DLBCL. Median follow up was 1.7 (0-13) years. The GCB-DLBCL was associated with inferior 5-year overall survival at 44% (95%CI, 36-52) versus 64% (95%CI, 54-77) (P = .004) and a higher relapse incidence at 67% (95%CI, 58-74) versus 49% (95%CI, 35-60) (P = .01) in the non-GCB-DLBCL. The difference between GCB and non-GCB-DLBCL remained statistically significant in multivariate analysis. Additionally, response at the time of transplant was an independent prognostic factor. GCB-DLBCL was enriched in double-hit and triple hit phenotype based on available fluorescence in situ hybridization data. These results suggest an enrichment of high-risk genetic rearrangements in R/R GCB-DLBCL resulting in limited efficacy of auto-HCT.

Mutational Landscape of TdT+ Large B-cell Lymphomas Supports Their Distinction From B-lymphoblastic Neoplasms: A Multiparameter Study of a Rare and Aggressive Entity

In the current World Health Organization classification, terminal deoxynucleotidyl transferase (TdT) expression in a high grade/large cell B-cell lymphoma (LBCL) indicates a B-lymphoblastic lymphoma/leukemia (B-LBL), although TdT expression in what appear to be mature LBCL or following mature B-cell neoplasms is reported. The frequency of TdT+ LBCL, how to best categorize these cases, and their clinicopathologic features, molecular landscape, and relationship to classic B-LBL remain to be better defined. TdT expression was therefore assessed in 258 LBCL and the results correlated with the cytologic, phenotypic, and cytogenetic findings. Targeted mutational analysis, review of prior biopsies, and assessment of clinical associations was performed in the 6 cases with >10% TdT+ cells. All 6 TdT+ LBCL were blastoid-appearing, CD34-, MYC+, BCL2+, and had MYC rearrangements (R) (5/6 with BCL2 and/or BCL6-R). 5/6 had a prior TdT- LBCL and/or follicular lymphoma and all had an aggressive course. Fifteen nonsynonymous variants in 11 genes were seen in the 4/5 tested cases with mutations. TdT+ and TdT- areas in 1 case showed identical mutations. The mutational profiles were more like those reported in germinal center B-cell type-diffuse LBCL rather than B-LBL. Evolution from preceding TdT- lymphomas was nondivergent in 1/3 tested cases and partially divergent in 2. The clinicopathologic and cytogenetic features of these 6 cases were similar to those found in a meta-analysis that included additional cases of TdT+ LBCL or B-LBL following follicular lymphoma. Thus, TdT+, CD34- large B-cell neoplasms with MYC rearrangements and often a "double hit" are rare, frequently a transformational event and aggressive but are distinct from classic B-LBL.

MYC Ran Up the Clock: The Complex Interplay between MYC and the Molecular Circadian Clock in Cancer

The MYC oncoprotein and its family members N-MYC and L-MYC are known to drive a wide variety of human cancers. Emerging evidence suggests that MYC has a bi-directional relationship with the molecular clock in cancer. The molecular clock is responsible for circadian (~24 h) rhythms in most eukaryotic cells and organisms, as a mechanism to adapt to light/dark cycles. Disruption of human circadian rhythms, such as through shift work, may serve as a risk factor for cancer, but connections with oncogenic drivers such as MYC were previously not well understood. In this review, we examine recent evidence that MYC in cancer cells can disrupt the molecular clock; and conversely, that molecular clock disruption in cancer can deregulate and elevate MYC. Since MYC and the molecular clock control many of the same processes, we then consider competition between MYC and the molecular clock in several select aspects of tumor biology, including chromatin state, global transcriptional profile, metabolic rewiring, and immune infiltrate in the tumor. Finally, we discuss how the molecular clock can be monitored or diagnosed in human tumors, and how MYC inhibition could potentially restore molecular clock function. Further study of the relationship between the molecular clock and MYC in cancer may reveal previously unsuspected vulnerabilities which could lead to new treatment strategies.

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.

Impaired ribosome biogenesis checkpoint activation induces p53-dependent MCL-1 degradation and MYC-driven lymphoma death

MYC-driven B-cell lymphomas are addicted to increased levels of ribosome biogenesis (RiBi), offering the potential for therapeutic intervention. However, it is unclear whether inhibition of RiBi suppresses lymphomagenesis by decreasing translational capacity and/or by p53 activation mediated by the impaired RiBi checkpoint (IRBC). Here we generated Eμ-Myc lymphoma cells expressing inducible short hairpin RNAs to either ribosomal protein L7a (RPL7a) or RPL11, the latter an essential component of the IRBC. The loss of either protein reduced RiBi, protein synthesis, and cell proliferation to similar extents. However, only RPL7a depletion induced p53-mediated apoptosis through the selective proteasomal degradation of antiapoptotic MCL-1, indicating the critical role of the IRBC in this mechanism. Strikingly, low concentrations of the US Food and Drug Administration-approved anticancer RNA polymerase I inhibitor Actinomycin D (ActD) dramatically prolonged the survival of mice harboring Trp53+/+;Eμ-Myc but not Trp53-/-;Eμ-Myc lymphomas, which provides a rationale for treating MYC-driven B-cell lymphomas with ActD. Importantly, the molecular effects of ActD on Eμ-Myc cells were recapitulated in human B-cell lymphoma cell lines, highlighting the potential for ActD as a therapeutic avenue for p53 wild-type lymphoma.

Loss of MYSM1 inhibits the oncogenic activity of cMYC in B cell lymphoma

MYSM1 is a chromatin‐binding protein, widely investigated for its functions in haematopoiesis in human and mouse; however, its role in haematologic malignancies remains unexplored. Here, we investigate the cross‐talk between MYSM1 and oncogenic cMYC in the transcriptional regulation of genes encoding ribosomal proteins, and the implications of these mechanisms for cMYC‐driven carcinogenesis. We demonstrate that in cMYC‐driven B cell lymphoma in mouse models, MYSM1‐loss represses ribosomal protein gene expression and protein synthesis. Importantly, the loss of MYSM1 also strongly inhibits cMYC oncogenic activity and protects against B cell lymphoma onset and progression in the mouse models. This advances the understanding of the molecular and transcriptional mechanisms of lymphomagenesis, and suggests MYSM1 as a possible drug target for cMYC‐driven malignancies.

Novel Biological Insights and New Developments in Management of Burkitt Lymphoma and High-Grade B-Cell Lymphoma

OPINION STATEMENT

Burkitt lymphoma (BL) is highly curable, and prompt institution of therapy is critical to achieving optimal outcomes. Although current "standard" approaches are very effective in disease eradication, treatment-related toxicity makes optimal delivery of curative therapy a challenge, especially in older and immunocompromised individuals. Reduced intensity approaches with fewer toxic complications have been the focus of some recent studies. A critical question is if they can replace "standard" approaches by maintaining high curability with improved tolerability. Additionally, new molecular insights in BL biology suggest that in the future, "targeted therapy" approaches may be feasible using small molecule inhibitors and novel strategies. Recently, a new category of aggressive lymphoma named "high-grade B-cell lymphoma (HGBL) with MYC and BCL2 and/or BCL6 translocations" has been recognized. This category overlaps clinically and biologically with BL and has an inferior prognosis compared to most B-cell lymphomas, and the optimal approach to its management remains, as yet, undefined. In this review, we discuss the current landscape of BL treatment including recent results with low-intensity regimens and also consider current approaches to HGBL. We also explore how recently elucidated novel biological insights in BL biology may shape future therapeutic directions including the use of novel cellular therapy approaches.

Diffuse Large B-Cell Lymphoma: Recognition of Markers for Targeted Therapy

Diffuse large B-cell lymphomas (DLBCL)s, the most common type of Non-Hodgkin’s Lymphoma, constitute a heterogeneous group of disorders including different disease sites, strikingly diverse molecular features and a profound variability in the clinical behavior. Molecular studies and clinical trials have partially revealed the underlying causes for this variability and have made possible the recognition of some molecular variants susceptible of specific therapeutic approaches. The main histogenetic groups include the germinal center, activated B cells, thymic B cells and terminally differentiated B cells, a basic scheme where the large majority of DLBCL cases can be ascribed. The nodal/extranodal origin, specific mutational changes and microenvironment peculiarities provide additional layers of complexity. Here, we summarize the status of the knowledge and make some specific proposals for addressing the future development of targeted therapy for DLBC cases.

MYC rearrangement but not extra MYC copies is an independent prognostic factor in patients with mantle cell lymphoma

Mantle cell lymphoma (MCL) with MYC rearrangement (MYC-R) is rare and little is known about the importance of MYC extra copies (EC) in the absence of MYC-R in MCL patients. This study includes 88 MCL patients with MYC tested by fluorescence in situ hybridization and/or conventional cytogenetics, including 27 with MYC-R, 21 with MYC-EC, and 40 with normal (NL) MYC. MCL patients with MYC-R more often had blastoid/pleomorphic morphology; a higher frequency of CD10, MYC, and simultaneous MYC and BCL2 expression; a higher level of MYC; and a higher Ki67 proliferation rate (p<0.05) than those without MYC-R. Although patients with MYC-R more frequently received aggressive chemotherapy (p=0.001), their overall survival (OS) was significantly shorter than those without MYC-R. Compared with patients with MYC/BCL2 double hit lymphoma (DHL), patients with MYC-R MCL had a similar OS but more commonly had bone marrow involvement, stage 4 disease, and a different immunophenotype. MCL patients with MYC-EC showed an OS intermediate between those with MYC-R and MYC-NL, either all or only blastoid/pleomorphic MCL patients included. Multivariate analysis showed that MYC-R, but not MYC-EC, had an independent and negative impact on OS. In conclusion, MYC-R but not MYC-EC showed a higher MYC expression and is an adverse prognostic factor for MCL patients. Although the OS of MCL patients with MYC-R is similar to that of MYC/BCL2 DHL patients, these groups have different clinicopathologic features supporting the retention of MCL with MYC-R in the category of MCL, as recommended in the revised World Health Organization classification.

EBV and the Pathogenesis of NK/T Cell Lymphoma

Epstein-Barr virus (EBV) is a ubiquitous gamma herpes virus with tropism for B cells. EBV is linked to the pathogenesis of B cell, T cell and NK cell lymphoproliferations, with extranodal NK/T cell lymphoma, nasal type (ENKTCL) being the prototype of an EBV-driven lymphoma. ENKTCL is an aggressive neoplasm, particularly widespread in East Asia and the native population of Latin America, which suggests a strong genetic predisposition. The link between ENKTCL and different populations has been partially explored. EBV genome sequencing analysis recognized two types of strains and identified variants of the latent membrane protein 1 (LMP1), which revealed different oncogenic potential. In general, most ENKTCL patients carry EBV type A with LMP1 wild type, although the LMP1 variant with a 30 base pair deletion is also common, especially in the EBV type B, where it is necessary for oncogenic transformation. Contemporary high-throughput mutational analyses have discovered recurrent gene mutations leading to activation of the JAK-STAT pathway, and mutations in other genes such as BCOR, DDX3X and TP53. The genomic landscape in ENKTCL highlights mechanisms of lymphomagenesis, such as immune response evasion, secondary to alterations in signaling pathways or epigenetics that directly or indirectly interfere with oncogenes or tumor suppressor genes. This overview discusses the most important findings of EBV pathogenesis and genetics in ENKTCL.

Non-coding RNAs (miRNAs and lncRNAs) and their roles in lymphogenesis in all types of lymphomas and lymphoid malignancies

Contemporary developments in molecular biology have been combined with discoveries on the analysis of the role of all non-coding RNAs (ncRNAs) in human diseases, particularly in cancer, by examining their roles in cells. Currently, included among these common types of cancer, are all the lymphomas and lymphoid malignancies, which represent a diverse group of neoplasms and malignant disorders. Initial data suggest that non-coding RNAs, particularly long ncRNAs (lncRNAs), play key roles in oncogenesis and that lncRNA-mediated biology is an important key pathway to cancer progression. Other non-coding RNAs, termed microRNAs (miRNAs or miRs), are very promising cancer molecular biomarkers. They can be detected in tissues, cell lines, biopsy material and all biological fluids, such as blood. With the number of well-characterized cancer-related lncRNAs and miRNAs increasing, the study of the roles of non-coding RNAs in cancer is bringing forth new hypotheses of the biology of cancerous cells. For the first time, to the best of our knowledge, the present review provides an up-to-date summary of the recent literature referring to all diagnosed ncRNAs that mediate the pathogenesis of all types of lymphomas and lymphoid malignancies.