Molecular pathogenesis of splenic and nodal marginal zone lymphoma

Subtype-WGME enables whole-genome-wide multi-omics cancer subtyping

We present an innovative strategy for integrating whole-genome-wide multi-omics data, which facilitates adaptive amalgamation by leveraging hidden layer features derived from high-dimensional omics data through a multi-task encoder. Empirical evaluations on eight benchmark cancer datasets substantiated that our proposed framework outstripped the comparative algorithms in cancer subtyping, delivering superior subtyping outcomes. Building upon these subtyping results, we establish a robust pipeline for identifying whole-genome-wide biomarkers, unearthing 195 significant biomarkers. Furthermore, we conduct an exhaustive analysis to assess the importance of each omic and non-coding region features at the whole-genome-wide level during cancer subtyping. Our investigation shows that both omics and non-coding region features substantially impact cancer development and survival prognosis. This study emphasizes the potential and practical implications of integrating genome-wide data in cancer research, demonstrating the potency of comprehensive genomic characterization. Additionally, our findings offer insightful perspectives for multi-omics analysis employing deep learning methodologies.

Molecular Pathology of Mature Lymphoid Malignancies

Lymphoid malignancies are a broad and heterogeneous group of neoplasms. In the past decade, the genetic landscape of these tumors has been explored and cataloged in fine detail offering a glimpse into the mechanisms of lymphomagenesis and new opportunities to translate these findings into patient management. A myriad of studies have demonstrated both distinctive and overlapping molecular and chromosomal abnormalities that have influenced the diagnosis and classification of lymphoma, disease prognosis, and treatment selection.

Plasticity in Classical Hodgkin Composite Lymphomas: A Systematic Review

The co-occurrence of several lymphomas in a patient defines composite/synchronous lymphoma. A common cellular origin has been reported for both contingents of such entities. In the present review, we aimed to gather the available data on composite lymphomas associating a classical Hodgkin lymphoma (cHL) with another lymphoma, to better understand the plasticity of mature B and T-cells. This review highlights that >70% of patients with a composite lymphoma are ≥55 years old, with a male predominance. The most reported associations are cHL with follicular lymphoma or diffuse large B-cell lymphoma, with over 130 cases reported. The cHL contingent is often of mixed cellularity type, with a more frequent focal/weak CD20 expression (30% to 55.6%) compared to de novo cHL, suggesting a particular pathophysiology. Moreover, Hodgkin cells may express specific markers of the associated lymphoma (e.g., BCL2/BCL6 for follicular lymphoma and Cyclin D1 for mantle cell lymphoma), sometimes combined with common BCL2/BCL6 or CCND1 rearrangements, respectively. In addition, both contingents may share similar IgH/IgK rearrangements and identical pathogenic variants, reinforcing the hypothesis of a common clonal origin. Finally, cHL appears to be endowed with a greater plasticity than previously thought, supporting a common clonal origin and a transdifferentiation process during lymphomagenesis of composite lymphomas.

KRAS and RAS-MAPK Pathway Deregulation in Mature B Cell Lymphoproliferative Disorders

KRAS mutations account for the most frequent mutations in human cancers, and are generally correlated with disease aggressiveness, poor prognosis, and poor response to therapies. KRAS is required for adult hematopoiesis and plays a key role in B cell development and mature B cell proliferation and survival, proved to be critical for B cell receptor-induced ERK pathway activation. In mature B cell neoplasms, commonly seen in adults, KRAS and RAS-MAPK pathway aberrations occur in a relevant fraction of patients, reaching high recurrence in some specific subtypes like multiple myeloma and hairy cell leukemia. As inhibitors targeting the RAS-MAPK pathway are being developed and improved, it is of outmost importance to precisely identify all subgroups of patients that could potentially benefit from their use. Herein, we review the role of KRAS and RAS-MAPK signaling in malignant hematopoiesis, focusing on mature B cell lymphoproliferative disorders. We discuss KRAS and RAS-MAPK pathway aberrations describing type, incidence, mutual exclusion with other genetic abnormalities, and association with prognosis. We review the current therapeutic strategies applied in mature B cell neoplasms to counteract RAS-MAPK signaling in pre-clinical and clinical studies, including most promising combination therapies. We finally present an overview of genetically engineered mouse models bearing KRAS and RAS-MAPK pathway aberrations in the hematopoietic compartment, which are valuable tools in the understanding of cancer biology and etiology.

The Relevance of Additional Immunohistochemical Markers on the Differential Diagnosis of Small B-Cell Lymphomas: A Case-control Study

Objective:

Clinical and pathological differential diagnosis of small B-cell lymphomas (SBCLs) is still controversial and may be difficult due to their overlapping morphology, phenotype, and differentiation to plasma cells. We aimed to examine the expression of the immune receptor translocation-associated protein 1 (IRTA1), myeloid cell nuclear differentiation antigen (MNDA), lymphoid enhancer-binding factor-1 (LEF1), and stathmin 1 (STMN1) markers in SBCL cases involving different sites that may have plasma cell differentiation.

Materials and Methods:

We studied 154 tissue samples with lymphoma involvement from 116 patients and evaluated the staining distribution of the markers. Expressions were evaluated in 21 chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), 7 follicular lymphoma (FL), 14 nodal marginal zone lymphoma, 17 extranodal marginal zone lymphoma, 55 splenic marginal zone lymphoma, 22 marginal zone lymphoma-not otherwise specified, and 18 lymphoplasmacytic lymphoma/Waldenström macroglobulinemia cases by immunohistochemistry.

Results:

The results confirmed that LEF1 was the most sensitive and specific marker for CLL/SLL and STMN1 was the most sensitive and specific marker for FL (p<0.001). MNDA and IRTA1 were useful markers to distinguish marginal zone lymphomas.

Conclusion:

Our results suggest that LEF1 for CLL/SLL and STMN1 for FL are reliable markers. LEF1, MNDA, STMN1, and IRTA1 are helpful with other routinely used immunohistochemical markers in a diagnostic algorithm considering their limitations.

Molecular Pathology of Mature Lymphoid Malignancies

Lymphoid malignancies are a broad and heterogeneous group of neoplasms. In the past decade, the genetic landscape of these tumors has been explored and cataloged in fine detail offering a glimpse into the mechanisms of lymphomagenesis and new opportunities to translate these findings into patient management. A myriad of studies have demonstrated both distinctive and overlapping molecular and chromosomal abnormalities that have influenced the diagnosis and classification of lymphoma, disease prognosis, and treatment selection.

Deciphering the genetic landscape of pulmonary lymphomas

Pulmonary lymphoid malignancies comprise various entities, 80% of them are pulmonary marginal zone B-cell lymphomas (PMZL). So far, little is known about point mutations in primary pulmonary lymphomas. We characterized the genetic landscape of primary pulmonary lymphomas using a customized high-throughput sequencing gene panel covering 146 genes. Our cohort consisted of 28 PMZL, 14 primary diffuse large B-cell lymphomas (DLBCL) of the lung, 7 lymphomatoid granulomatoses (LyG), 5 mature small B-cell lymphomas and 16 cases of reactive lymphoid lesions. Mutations were detected in 22/28 evaluable PMZL (median 2 mutation/case); 14/14 DLBCL (median 3 mutations/case) and 4/7 LyG (1 mutation/case). PMZL showed higher prevalence for mutations in chromatin modifier-encoding genes (44% of mutant genes), while mutations in genes related to the NF-κB pathway were less common (24% of observed mutations). There was little overlap between mutations in PMZL and DLBCL. MALT1 rearrangements were more prevalent in PMZL than BCL10 aberrations, and both were absent in DLBCL. LyG were devoid of gene mutations associated with immune escape. The mutational landscape of PMZL differs from that of extranodal MZL of other locations and also from splenic MZL. Their landscape resembles more that of nodal MZL, which also show a predominance of mutations of chromatin modifiers. The different mutational composition of pulmonary DLBCL compared to PMZL suggests that the former probably do not present transformations. DLBCL bear more mutations/case and immune escape gene mutations compared to LyG, suggesting that EBV infection in LyG may substitute for mutations.

Progranulin depletion inhibits proliferation via the transforming growth factor beta/SMAD family member 2 signaling axis in Kasumi-1 cells

Progranulin is an autocrine growth factor that promotes proliferation, migration, invasion, and chemoresistance of various cancer cells. These mechanisms mainly depend on the protein kinase B (Akt)/mechanistic target of rapamycin (mTOR) pathway. Recent studies have shown that patients with hematopoietic cancer have elevated serum progranulin levels. Thus, the current study aimed to investigate the role of progranulin in hematopoietic cancer cells and how it modulates their proliferation. Both knockdown of progranulin and progranulin neutralizing antibody treatment inhibited proliferation in several human hematopoietic cancer cell lines. Moreover, progranulin depletion not only decreases the phosphorylation level of the Akt/mTOR pathway but also, surprisingly, increases the expression of transforming growth factor-beta (TGF-β) and phosphorylation of mothers against decapentaplegic homolog 2 (SMAD2) in Kasumi-1 cell. Furthermore, LY2109761, an inhibitor of TGF-β receptor type I/II kinase, and TGF-β neutralizing antibody blocked the inhibition of proliferation induced by progranulin depletion. These data provide new insights that progranulin alters cell proliferation via the TGF-β axis and progranulin could be a new therapeutic target for hematopoietic cancers.

Splenic marginal zone lymphoma: a case report and literature review

BACKGROUND

Splenic marginal zone lymphoma (SMZL) is a rare non-Hodgkin lymphoma, and much little is known about its clinical characteristics and management strategies. Here we present a case of SMZL and review relevant literature to provide a better recognition of this disease entity.

CASE PRESENTATION

A 49-year-old Chinese female was admitted to our hospital with complaints of abdominal distension and acid reflux. Physical examinations and imaging investigations suggested the presence of splenomegaly. Laboratory workups revealed mildly reduced white blood cell count otherwise was not remarkable. The patient underwent splenectomy. Histological examination combined with immunohistochemical analysis of the resected spleen confirmed the diagnosis of SMZL. The patient recovered uneventfully during follow-ups.

CONCLUSIONS

Due to the rarity and unspecific clinical features, SMZL is extremely challenging to be diagnosed preoperatively. Patients with SMZL are generally associated with favorable prognosis. Combining the staging characteristics of non-Hodgkin's lymphoma and splenic primary lymphoma may assist in clinical staging management of SMZL.

Mechanisms of B Cell Receptor Activation and Responses to B Cell Receptor Inhibitors in B Cell Malignancies

The B cell receptor (BCR) pathway has been identified as a potential therapeutic target in a number of common B cell malignancies, including chronic lymphocytic leukemia, diffuse large B cell lymphoma, Burkitt lymphoma, follicular lymphoma, mantle cell lymphoma, marginal zone B cell lymphoma, and Waldenstrom's macroglobulinemia. This finding has resulted in the development of numerous drugs that target this pathway, including various inhibitors of the kinases BTK, PI3K, and SYK. Several of these drugs have been approved in recent years for clinical use, resulting in a profound change in the way these diseases are currently being treated. However, the response rates and durability of responses vary largely across the different disease entities, suggesting a different proportion of patients with an activated BCR pathway and different mechanisms of BCR pathway activation. Indeed, several antigen-dependent and antigen-independent mechanisms have recently been described and shown to result in the activation of distinct downstream signaling pathways. The purpose of this review is to provide an overview of the mechanisms responsible for the activation of the BCR pathway in different B cell malignancies and to correlate these mechanisms with clinical responses to treatment with BCR inhibitors.

Primary central nervous system marginal zone B-cell lymphoma arising from the dural meninges: A case report and review of literature

Primary central nervous system (CNS) marginal zone B-cell lymphoma (MZBCL) arising from the dural meninges is a rare but indolent disease. This malignancy can present in various ways, hence making it difficult to diagnose. Biopsy results dictate an appropriate treatment plan, which commonly consists of a combination of surgical resection, whole brain radiotherapy and systemic therapy.

Marginal zone B-cell lymphoma: lessons from Western and Eastern diagnostic approaches

Marginal zone B-cell lymphomas (MZLs) are a group of clinically indolent B-cell lymphomas postulated to derive from memory B lymphocytes in the 'marginal zone' of secondary lymphoid tissue. Today, MZL is recognised as a nosological umbrella term encompassing distinct entities with some shared phenotypic and genotypic features, including extranodal marginal zone B-cell lymphoma (EMZL) or mucosa-associated lymphoid tissue (MALT) lymphoma, splenic MZL, and nodal MZL, accounting for approximately 70%, 20%, and 10% of MZLs, respectively. These lymphomas share some phenotypic and genotypic features and have some variants and related provisional diseases, but are different in regards to their clinical and molecular characteristics. In addition, they are frequently associated with chronic antigenic stimulation represented either by infectious agents, particularly bacteria and viruses, or autoimmune diseases as exemplified by Sjögren syndrome, Hashimoto thyroiditis, and newly recognised IgG4-related disease. Furthermore, several chromosomal translocations have been identified in EMZL. In this review, we will focus on the updated histopathological criteria and the main problems with differential diagnoses in order to aid the diagnostic approach in our routine practice.

The NOTCH Pathway and Its Mutations in Mature B Cell Malignancies

The systematic application of next-generation sequencing to large cohorts of oncologic samples has opened a Pandora's box full of known and novel genetic lesions implicated in different steps of cancer development and progression. Narrowing down to B cell malignancies, many previously unrecognized genes emerged as recurrently mutated. The challenge now is to determine how the mutation in a given gene affects the biology of the disease, paving the way to functional genomics studies. Mutations in NOTCH family members are shared by several disorders of the B series, even if with variable frequencies and mutational patterns. In silico predictions, revealed that mutations occurring in NOTCH receptors, despite being qualitatively different, may have similar effects on protein processing, ultimately leading to enhanced pathway activation. The discovery of mutations occurring also in downstream players, either potentiating positive signals or compromising negative regulators, indicates that multiple mechanisms in neoplastic B cells concur to activate NOTCH pathway. These findings are supported by results obtained in chronic lymphocytic leukemia and splenic marginal zone B cell lymphoma where deregulation of NOTCH signaling has been functionally characterized. The emerging picture confirms that NOTCH signaling is finely tuned in cell- and microenvironment-dependent ways. In B cell malignancies, it contributes to the regulation of proliferation, survival and migration. However, deeper biological studies are needed to pinpoint the contribution of NOTCH in the hierarchy of events driving B cells transformation, keeping in mind its role in normal B cells development. Because of its relevance in leukemia and lymphoma biology, the NOTCH pathway might represent an appealing therapeutic target: the next few years will tell whether this potential will be fulfilled.

Targeted deep sequencing of gastric marginal zone lymphoma identified alterations of TRAF3 and TNFAIP3 that were mutually exclusive for MALT1 rearrangement

Gastric extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue is a distinct entity in that Helicobacter pylori infection plays the most important causative role in the development of the disease. To investigate the genomic alteration in gastric marginal zone lymphoma that was resistant to the H. pylori eradication therapy, we analyzed 19 cases of the gastric marginal zone lymphoma using fluorescence in situ hybridization for MALT1, BCL10 rearrangement, and targeted sequencing using an Illumina platform. Major genetic alterations affected genes involved in nuclear factor (NF)-κB pathway activation and included MALT1 rearrangement (39%), and somatic mutations of TRAF3 (21%), TNFAIP3 (16%), and NOTCH1 (16%). In the MALT1 rearrangement-negative group, disruptive somatic mutations of TRAF3 were the most common alterations (4/12, 33%), followed by somatic mutations of TNFAIP3 (3/12, 25%), and NOTCH1 (3/12, 25%). The present study confirms that genes involved in activation of NF-κB-signaling pathways are a major driver in oncogenesis of H. pylori eradication-resistant gastric marginal zone lymphoma and revealed that TRAF3 mutation is a major contributor in MALT1 rearrangement-negative gastric marginal zone lymphoma.

Copanlisib for treatment of B-cell malignancies: the development of a PI3K inhibitor with considerable differences to idelalisib

On the occasion of its recent approval for relapsed follicular lymphoma, we review the design and development of the pan-class I PI3K inhibitor copanlisib as a drug for the treatment of B-cell malignancies in comparison with other kinase inhibitors targeting B-cell-receptor signaling, in particular with strictly isoform-δ-selective idelalisib. In agreement with previously defined PI3K-inhibitor chemotypes, the 2,3-dihydroimidazo[1,2-c]quinazoline scaffold of copanlisib adopts a flat conformation in the adenine-binding pocket of the catalytic p110 subunit and further extends into a deeper-affinity pocket in contrast to idelalisib, the quinazoline moiety of which is accommodated in a newly created selectivity pocket. Copanlisib shows higher potency than other clinically developed PI3K inhibitors against all four class I isoforms, with approximately tenfold preference for p110α and p110δ. Owing to its potency and isoform profile, copanlisib exhibits cell-type-specific cytotoxicity against primary chronic lymphocytic leukemia cells and diffuse large B-cell lymphoma (DLBCL) cell lines at nanomolar concentrations. Moreover, copanlisib differs from idelalisib in regard to intravenous versus oral administration and weekly versus twice-daily dosing. In regard to adverse effects, intermittent intravenous treatment with copanlisib leads to fewer gastrointestinal toxicities compared with continuous oral dosing of idelalisib. In relapsed follicular lymphoma, copanlisib appears more effective and especially better tolerated than other targeted therapies. Copanlisib extends existing treatment options for this subtype of indolent non-Hodgkin lymphoma and also shows promising response rates in DLBCL, especially of the activated B-cell type.

Splenic marginal zone lymphomas in acquired C1-inhibitor deficiency: clinical and molecular characterization

Angioedema due to acquired deficiency of the inhibitor of the first component of complement (C1-INH) is a rare disease known as acquired angioedema (AAE). About 70% of patients with AEE display autoantibodies to C1-INH, the remaining patients have no antibodies to C1-INH. The clinical features of C1-INH deficiency include recurrent, self-limiting local swellings involving the skin, the gastrointestinal tract, and the upper respiratory tract. Swelling is due to accumulation of bradykinin released from high molecular weight kininogen. Patients with angioedema due to acquired C1 inhibitor deficiency (AEE) often have an associated lymphoproliferative disease including Non-Hodgkin Lymphomas (NHL). Among AAE patients with NHL, splenic marginal zone lymphoma (SMZL) has a higher prevalence (66%) compared to general population (2%) In the present study, we focused on patients with SMZL in AAE. We found 24 AAE patients with NHL and, among them 15 SMZL (62.5% of all NHL). We found NOTCH 2 activation in 4 /15 patients (26.6%) with SMZL, while no patients carried MYD 88 or BIRC3 mutations. Restricted immunoglobulin gene repertoire analysis showed that the IGHV1-2*04 allele was found to be over-represented in the group of patients with or without lymphoproliferative disease presenting with autoantibodies to C1-INH (41 of 55 (75%) of patients; p value 0.011) when compared to the control group of patients with AEE without antibodies to C1-INH, (7 of 27 (26%) of patients). Immunophenotyping failed to demonstrate the presence of autoreactive clones against C1-inhibitor. Taken together, these findings suggest a role for antigenic stimulation in the pathogenesis of lymphomas associated with AEE.

Working Toward a Genomic Prognostic Classification of Waldenström Macroglobulinemia: C-X-C Chemokine Receptor Type 4 Mutation and Beyond

Waldenström macroglobulinemia is a rare indolent B-cell lymphoma. Whole-exome sequencing studies have improved our knowledge of the Waldenström macroglobulinemia mutational landscape. The MYD88 L265P mutation is present in nearly 90% of patients with Waldenström macroglobulinemia. CXCR4 mutations are identified in approximately 30% of MYD88L265P cases and have been associated with ibrutinib resistance in clinical trials. Mutations in CD79B, ARID1a, or TP53 were described at lower frequency. Deciphering the earliest initiating lesions and identifying the molecular alterations leading to disease progression currently represent important goals in the future to identify the most relevant targets for precision therapy in Waldenström macroglobulinemia.

Follicular Lymphoma: Past, Present, and Future

OPINION STATEMENT

Even in the modern era, follicular lymphoma (FL) remains largely an incurable but treatable disease with both standard and novel treatment modalities. Despite the abundance of efficacious treatment modalities currently available, there is no universally agreed upon standard approach to treatment for patients with FL, particularly in the relapsed/refractory (R/R) setting. There is an increasing need for better tools to risk-stratify patients and to identify those likely to experience relapse early. Additionally, the use of gene expression profiling and next-generation sequencing techniques in recent years has led to a wealth of knowledge regarding the molecular drivers of lymphomagenesis; however, much of this knowledge is not currently applicable on a day to day basis in the clinic setting. Further studies are needed to determine a validated, clinically relevant predictive model that incorporates patient factors and molecular factors that will guide clinicians on the most effective treatment strategy. With many questions left unanswered, it is our opinion that the treatment of FL and sequencing of therapy in the R/R setting should be a personalized approach that balances patient-specific factors such as preferences and comorbidities with treatment-related factors such as known response rates and toxicity profiles.

Recent advances in understanding the biology of marginal zone lymphoma

There are three different marginal zone lymphomas (MZLs): the extranodal MZL of mucosa-associated lymphoid tissue (MALT) type (MALT lymphoma), the splenic MZL, and the nodal MZL. The three MZLs share common lesions and deregulated pathways but also present specific alterations that can be used for their differential diagnosis. Although trisomies of chromosomes 3 and 18, deletions at 6q23, deregulation of nuclear factor kappa B, and chromatin remodeling genes are frequent events in all of them, the three MZLs differ in the presence of recurrent translocations, mutations affecting the NOTCH pathway, and the transcription factor Kruppel like factor 2 ( KLF2) or the receptor-type protein tyrosine phosphatase delta ( PTPRD). Since a better understanding of the molecular events underlying each subtype may have practical relevance, this review summarizes the most recent and main advances in our understanding of the genetics and biology of MZLs.

High-throughput sequencing of nodal marginal zone lymphomas identifies recurrent BRAF mutations

Nodal marginal zone lymphoma (NMZL) is a rare small B-cell lymphoma lacking disease-defining phenotype and precise diagnostic markers. To better understand the mutational landscape of NMZL, particularly in comparison to other nodal small B-cell lymphomas, we performed whole-exome sequencing, targeted high-throughput sequencing, and array-comparative genomic hybridization on a retrospective series. Our study identified for the first time recurrent, diagnostically useful, and potentially therapeutically relevant BRAF mutations in NMZL. Sets of somatic mutations that could help to discriminate NMZL from other closely related small B-cell lymphomas were uncovered and tested on unclassifiable small B-cell lymphoma cases, in which clinical, morphological, and phenotypical features were equivocal. Application of targeted gene panel sequencing gave at many occasions valuable clues for more specific classification.

First-line treatment with bendamustine and rituximab, in patients with intermediate-/high-risk splenic marginal zone lymphomas

Splenic marginal zone lymphomas (SMZLs) are rare indolent B cell neoplasms that affect the spleen, bone marrow, and blood. Although they have an indolent course in the majority of patients, who have a median survival of 8-10 years, ∼ 30% may experience a worse outcome. The prognostic criteria of progression are lymph node and extra-nodal involvement, high lymphocyte counts, anaemia, and thrombocytopenia. The treatment of SMZLs include a "wait and watch strategy", splenectomy, and alkylating agents ± rituximab. We here describe data relating to 70 patients with intermediate-/high-risk SMZLs, who received rituximab/bendamustine as first-line treatment for a median of 60 days (range 1-75) after diagnosis. Sixty patients (86%) achieved a complete response (CR), and seven (10%) a partial response (PR). Three patients (4.3%) experienced disease progression (PD). The median duration of remission was 18 months. Side effects were generally mild. Our findings suggest that rituximab/bendamustine is a feasible treatment option in patients with intermediate-/high-risk SMZLs.