Genomic and gene expression profiling defines indolent forms of mantle cell lymphoma

SOHO State of the Art Updates and Next Questions: Treatment Evolution of Mantle Cell Lymphoma: Navigating the Different Entities and Biological Heterogeneity of Mantle Cell Lymphoma in 2024

Progress in mantle cell lymphoma (MCL) has led to significant improvement in outcomes of patients even in the real world (RW) setting albeit to a lesser degree. In parallel to the demonstration of benefit using combination therapy with rituximab plus high-dose cytarabine (R-AraC) as well as dose intensive therapy-autologous stem cell transplantation (DIT-ASCT) consolidation and maintenance, it became clear over the last 2 decades that MCL is a highly heterogenous disease at the molecular level, explaining differences observed in clinical behavior and response to therapy. While clinical prognostic factors and models have helped stratify patients with distinct outcomes, they failed to help guide therapy. The identification of molecular high-risk (HR) features, in particular, but not only, p53 aberrations (including mutations and deletions [del]), as well as complex karyotype (CK), has allowed to identify subsets of patients with poorer outcomes (median overall survival [OS] <2 years) regardless of conventional therapies used. The constant pattern of relapse seen in MCL has fueled sustained and productive efforts, with 7 novel agents approved in the United States (US), showing high and durable efficacy even in HR and chemo-refractory patients and likely curing a subset of patients in the relapsed or refractory (R/R) setting. Progress in diagnostics, in particular next-generation sequencing (NGS), which is accessible in routine practice nowadays, can help recognize patients with HR features, well beyond MIPI or Ki-67 prognostication, although the impact on decision making is still unclear. The era of integrating novel agents into our prior standard of care (SOC) has begun with a confirmed benefit, for example, ibrutinib (Ib) in the TRIANGLE study, defining the first new potential SOC in younger patients in over 30 years. Expanding on novel agents, either in combination, sequentially or to replace chemotherapy altogether, using biological doublets or triplets has led to a median progression-free survival (PFS) in excess of 72 months, certainly competitive with prior SOC and will continue to reshape the management of MCL patients. Achieving minimal residual disease negative (MRD-ve) status is becoming a new endpoint in MCL, and customizing maintenance and/or de-escalation/consolidation strategies is within reach, although it will require prospective, built-in MRD-based approaches, with the goal of eliminating subclinical disease and not simply delaying time to relapse. Taking into account the biological diversity of MCL is now feasible in routine clinical practice and has already helped recognize what not to do for HR patients (i.e., avoid intensive induction chemotherapy and/or ASCT for p53 mutated patients) as well as identify promising novel options. Ongoing and future work will help expand on these dedicated approaches, to further improve the management and outcomes of all MCL patients.

Insight into Mantle Cell Lymphoma Pathobiology, Diagnosis, and Treatment Using Network-Based and Drug-Repurposing Approaches

Mantle cell lymphoma (MCL) is a rare, incurable, and aggressive B-cell non-Hodgkin lymphoma (NHL). Early MCL diagnosis and treatment is critical and puzzling due to inter/intra-tumoral heterogeneity and limited understanding of the underlying molecular mechanisms. We developed and applied a multifaceted analysis of selected publicly available transcriptomic data of well-defined MCL stages, integrating network-based methods for pathway enrichment analysis, co-expression module alignment, drug repurposing, and prediction of effective drug combinations. We demonstrate the "butterfly effect" emerging from a small set of initially differentially expressed genes, rapidly expanding into numerous deregulated cellular processes, signaling pathways, and core machineries as MCL becomes aggressive. We explore pathogenicity-related signaling circuits by detecting common co-expression modules in MCL stages, pointing out, among others, the role of VEGFA and SPARC proteins in MCL progression and recommend further study of precise drug combinations. Our findings highlight the benefit that can be leveraged by such an approach for better understanding pathobiology and identifying high-priority novel diagnostic and prognostic biomarkers, drug targets, and efficacious combination therapies against MCL that should be further validated for their clinical impact.

Mantle Cell Lymphoma Under the Scope of Personalized Medicine: Perspective and Directions

Mantle cell lymphoma (MCL) is a rare, incurable non-Hodgkin's lymphoma characterized by naive B cells infiltrating the lymphoid follicle's mantle zone. A key feature of MCL is the cytogenetic abnormality t(11;14) (q13:q14), found in 95% of cases, leading to Cyclin D1 overexpression resulting in uncontrolled cell cycle progression and genetic instability. Occasionally, Cyclin D2 or D3 overexpression can substitute for Cyclin D1, causing similar effects. The transcription factor SOX11 is a hallmark of classical Cyclin D1-positive MCL and also in cases without the typical t(11;14) abnormality, making it an important diagnostic marker. MCL's development necessitates secondary genetic changes, including mutations in the ATM, TP53, and NOTCH1 genes, with the TP53 mutation being the only genetic biomarker with established clinical prognostic value. The Mantle Cell Lymphoma International Prognostic Index (MIPI) score, which considers age, performance status, serum LDH levels, and leukocyte count, stratifies patients into risk groups. Histologic variants of MCL, such as classic, blastoid, and pleomorphic, offer additional prognostic information. Recent research highlights new mutations potentially tied to specific populations among MCL patients, suggesting the benefit of personalized management for better predicting outcomes like progression-free survival. This approach could lead to more effective, risk-adapted treatment strategies. However, challenges remain in patient stratification and in developing new therapeutic targets for MCL. This review synthesizes current knowledge on genetic mutations in MCL and their impact on prognosis. It aims to explore the prognostic value of genetic markers related to population traits, emphasizing the importance of tailored molecular medicine in MCL.

SOX11 is a novel binding partner and endogenous inhibitor of SAMHD1 ara-CTPase activity in mantle cell lymphoma

ABSTRACT

Sterile alpha motif and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate triphosphohydrolase with ara-CTPase activity that confers cytarabine (ara-C) resistance in several hematological malignancies. Targeting SAMHD1's ara-CTPase activity has recently been demonstrated to enhance ara-C efficacy in acute myeloid leukemia. Here, we identify the transcription factor SRY-related HMG-box containing protein 11 (SOX11) as a novel direct binding partner and first known endogenous inhibitor of SAMHD1. SOX11 is aberrantly expressed not only in mantle cell lymphoma (MCL), but also in some Burkitt lymphomas. Coimmunoprecipitation of SOX11 followed by mass spectrometry in MCL cell lines identified SAMHD1 as the top SOX11 interaction partner, which was validated by proximity ligation assay. In vitro, SAMHD1 bound to the HMG box of SOX11 with low-micromolar affinity. In situ crosslinking studies further indicated that SOX11-SAMHD1 binding resulted in a reduced tetramerization of SAMHD1. Functionally, expression of SOX11 inhibited SAMHD1 ara-CTPase activity in a dose-dependent manner resulting in ara-C sensitization in cell lines and in a SOX11-inducible mouse model of MCL. In SOX11-negative MCL, SOX11-mediated ara-CTPase inhibition could be mimicked by adding the recently identified SAMHD1 inhibitor hydroxyurea. Taken together, our results identify SOX11 as a novel SAMHD1 interaction partner and its first known endogenous inhibitor with potentially important implications for clinical therapy stratification.

B-cell non-Hodgkin lymphomas

B-cell lymphomas occur with an incidence of 20 new cases per 100 000 people per year in high-income countries. They can affect any organ and are characterised by heterogeneous clinical presentations and courses, varying from asymptomatic, to indolent, to very aggressive cases. Since the topic of B-cell non-Hodgkin lymphomas was last reviewed in The Lancet in 2017, a deeper understanding of the biological background of this heterogeneous group of malignancies, the availability of new diagnostic methods, and the development and implementation of new targeted and immunotherapeutic approaches have improved our ability to treat patients. This Seminar provides an overview of the pathobiology, classification, and prognostication of B-cell non-Hodgkin lymphomas and summarises the current knowledge and standard of care regarding biology and clinical management of the most common subtypes of mature B-cell non-Hodgkin lymphomas. It also highlights new findings in deciphering the molecular background of disease development and the implementation of new therapeutic approaches, particularly those targeting the immune system.

Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissues: B-cell Neoplasms

We review B-cell neoplasms in the 5th edition of the World Health Organization classification of hematolymphoid tumors (WHO-HEM5). The revised classification is based on a multidisciplinary approach including input from pathologists, clinicians, and other experts. The WHO-HEM5 follows a hierarchical structure allowing the use of family (class)-level definitions when defining diagnostic criteria are partially met or a complete investigational workup is not possible. Disease types and subtypes have expanded compared with the WHO revised 4th edition (WHO-HEM4R), mainly because of the expansion in genomic knowledge of these diseases. In this review, we focus on highlighting changes and updates in the classification of B-cell lymphomas, providing a comparison with WHO-HEM4R, and offering guidance on how the new classification can be applied to the diagnosis of B-cell lymphomas in routine practice.

Epidemiological, clinical and therapeutic profiles of mantle cell lymphoma cared for in a Moroccan center: a review of 14 cases

Mantle cell lymphoma (MCL) accounts for 3-10% of non-Hodgkin's lymphomas (NHL). We identified 14 patients with mantle cell lymphoma, with an average number of 3.5 new cases/year. A male predominance was observed with a sex ratio equal to 6. The average age of our patients was 64.4±14.1 years, with an average diagnostic delay of 6.57 months. Regarding the clinical presentation, adenopathy was the most reported physical sign (78.6%) followed by B symptoms (57.1%). Disseminated stages were the most frequent in our series: stages IV (78.5%) and III (7.1%) versus stages I (0%) and II (7.1%). The extra-ganglionic localizations observed were hepatic 5 cases (31.1%), pulmonary 04 cases (25%), medullary 4 cases (25%), pleural 2 cases (12.5%) and prostate 1 case (6.2%). All diagnosed cases are mantle cell lymphomas, of which 12 cases (85.7%) are classical and 2 cases (14.3%) indolent. The high-risk group is, according to international prognostic index (MIPI) MCL prognostic score, the most represented in our series: 0-3 = 6 cases (42.9%), 6-11 = 8 cases (57.1%). The therapeutic protocol chosen 1st line: 9 patients treated with R-DHAP, three with R-CHOP, one with DHAOX and one with R-CVP. Second line: two patients treated with R-DHAP, one after R-CHOP and the other after R-CVP. Two patients received autologous hematopoietic stem cell transplant at the end of the treatment. The evolution was marked by the death of 7 patients, 3 lost to follow-up and 4 still followed. Additionally, the study highlights characteristics and treatment patterns of mantle cell lymphoma, emphasizing its predominance in males, delayed diagnosis, frequent dissemination, and high-risk classification, with chemotherapy as the primary treatment modality and a challenging prognosis contributing to a comprehensive understanding of mantle cell lymphoma presentation and management.

SOX11 is a novel binding partner and endogenous inhibitor of SAMHD1 ara-CTPase activity in mantle cell lymphoma

The sterile alpha motif and histidine-aspartate (HD) domain containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate triphosphohydrolase with ara-CTPase activity that confers cytarabine (ara-C) resistance in several haematological malignancies. Targeting SAMHD1's ara-CTPase activity has recently been demonstrated to enhance ara-C efficacy in acute myeloid leukemia. Here, we identify the transcription factor SRY-related HMG-box containing protein 11 (SOX11) as a novel direct binding partner and first known endogenous inhibitor of SAMHD1. SOX11 is aberrantly expressed not only in mantle cell lymphoma (MCL), but also in some Burkitt lymphomas. Co-immunoprecipitation of SOX11 followed by mass spectrometry in MCL cell lines identified SAMHD1 as the top SOX11 interaction partner which was validated by proximity ligation assay. In vitro, SAMHD1 bound to the HMG box of SOX11 with low-micromolar affinity. In situ crosslinking studies further indicated that SOX11-SAMHD1 binding resulted in a reduced tetramerization of SAMHD1. Functionally, expression of SOX11 inhibited SAMHD1 ara-CTPase activity in a dose-dependent manner resulting in ara-C sensitization in cell lines and in a SOX11-inducible mouse model of MCL. In SOX11-negative MCL, SOX11-mediated ara-CTPase inhibition could be mimicked by adding the recently identified SAMHD1 inhibitor hydroxyurea. Taken together, our results identify SOX11 as a novel SAMHD1 interaction partner and its first known endogenous inhibitor with potentially important implications for clinical therapy stratification.

Evaluation of clinical parameters and biomarkers in older, untreated mantle cell lymphoma patients receiving bendamustine-rituximab

Mantle cell lymphoma (MCL) is clinically and biologically heterogeneous. While various prognostic features have been proposed, none currently impact therapy selection, particularly in older patients, for whom treatment is primarily dictated by age and comorbidities. Herein, we undertook a comprehensive comparison of clinicopathological features in a cohort of patients 60 years and older, uniformly treated with bendamustine and rituximab, with a median survival of >8 years. The strongest prognostic indicators in this cohort were a high-risk call by a simplified MCL international prognostic index (s-MIPI) (HR: 3.32, 95% CI: 1.65-6.68 compared to low risk), a high-risk call by MCL35 (HR: 10.34, 95% CI: 2.37-45.20 compared to low risk) and blastoid cytology (HR: 4.21, 95% CR: 1.92-9.22 compared to classic). Patients called high risk by both the s-MIPI and MCL35 had the most dismal prognosis (HR: 11.58, 95% CI: 4.10-32.72), while those with high risk by either had a moderate but clinically relevant prognosis (HR: 2.95, 95% CI: 1.49-5.82). A robust assay to assess proliferation, such as MCL35, along with stringent guidelines for cytological evaluation of MCL, in combination with MIPI, may be a strong path to risk-stratify older MCL patients in future clinical trials.

Blastoid Variant of Mantle Cell Lymphoma with Extranodal Presentation and Aberrant CD10 Expression

Mantle cell lymphoma (MCL) constitutes 3%-10% of non-Hodgkin lymphoma and is characterized by t (11:14)(q13;q32). The common presentation is generalized lymphadenopathy with weight loss, infrequently night sweats, and fever. Among histological subtypes of MCL, the blastoid variant of MCL constitutes 10%-15% of all the cases. It is challenging to diagnose the blastoid variant of MCL based on its morphology alone as it mimics large B-cell lymphoma. Hence, the immunophenotyping and molecular studies aid in its correct diagnosis. We report an elderly man diagnosed with blastoid variant MCL. He presented with disseminated soft-tissue and subcutaneous nodules, and showed aberrant CD10 expression. Presentation of the extranodal site and aberrant CD10 expressions carries an overall poor prognosis. CD10-positive MCL can be mistaken for large B-cell lymphoma.

Adding venetoclax to lenalidomide and rituximab is safe and effective in patients with untreated mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare, incurable hematological malignancy with a heterogeneous presentation and clinical course. A wide variety of chemotherapy-based regimens are currently used in patients who are untreated. Over the last several years, several targeted or small-molecule therapies have shown efficacy in the relapsed/refractory setting and have since been explored in the frontline setting. Lenalidomide plus rituximab was explored in a phase 2 study of 38 patients with MCL who were untreated and ineligible to receive transplantation, in which the combination produced durable remissions. We looked to build upon this regimen by adding venetoclax to the combination. We conducted a multicenter, open-label, nonrandomized, single-arm study to evaluate this combination. We enrolled 28 unselected patients with untreated disease irrespective of age, fitness, or risk factors. Lenalidomide was dosed at 20 mg daily from days 1 to 21 of each 28-day cycle. The dose of venetoclax was determined using the time-to-event continual reassessment method. Rituximab was dosed at 375 mg/m2 weekly, starting on cycle 1, day 1 until cycle 2, day 1. No dose-limiting toxicities were noted. All patients were treated with venetoclax at the maximum tolerated dose of 400 mg daily. The most common adverse events were neutropenia and thrombocytopenia. The overall and complete response rates were 96% and 86%, respectively. In total, 86% of patients achieved minimal residual disease undetectability via next-generation sequencing. The median overall and progression-free survivals were not reached. The combination of lenalidomide, rituximab, and venetoclax is a safe and effective regimen in patients with untreated MCL. This trial was registered at www.clinicaltrials.gov as #NCT03523975.

Mantle cell lymphoma-Update on molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterized by its heterogenous behavior with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with very limited prognosis. The development and implementation of new targeted and immunotherapeutic approaches have already improved therapeutic options especially for refractory or relapsed disease. Nevertheless, to further optimize MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated in clinical patient management. This review summarizes the current knowledge and standard of care regarding biology and clinical management of MCL, highlighting the implementation of new therapeutic approaches especially targeting the immune system.

A novel patient-derived 3D model recapitulates mantle cell lymphoma lymph node signaling, immune profile and in vivo ibrutinib responses

Mantle cell lymphoma (MCL), a rare and aggressive B-cell non-Hodgkin lymphoma, mainly develops in the lymph node (LN) and creates a protective and immunosuppressive niche that facilitates tumor survival, proliferation and chemoresistance. To capture disease heterogeneity and tumor microenvironment (TME) cues, we have developed the first patient-derived MCL spheroids (MCL-PDLS) that recapitulate tumor oncogenic pathways and immune microenvironment in a multiplexed system that allows easy drug screening, including immunotherapies. MCL spheroids, integrated by tumor B cells, monocytes and autologous T-cells self-organize in disc-shaped structures, where B and T-cells maintain viability and proliferate, and monocytes differentiate into M2-like macrophages. RNA-seq analysis demonstrated that tumor cells recapitulate hallmarks of MCL-LN (proliferation, NF-kB and BCR), with T cells exhibiting an exhaustion profile (PD1, TIM-3 and TIGIT). MCL-PDLS reproduces in vivo responses to ibrutinib and demonstrates that combination of ibrutinib with nivolumab (anti-PD1) may be effective in ibrutinib-resistant cases by engaging an immune response with increased interferon gamma and granzyme B release. In conclusion, MCL-PDLS recapitulates specific MCL-LN features and in vivo responses to ibrutinib, representing a robust tool to study MCL interaction with the immune TME and to perform drug screening in a patient-derived system, advancing toward personalized therapeutic approaches.

How I manage mantle cell lymphoma: indolent versus aggressive disease

Mantle cell lymphoma (MCL) is a mature B-cell lymphoma with a variable clinical course and historically poor prognosis. Management is challenging in part due to the heterogeneity of the disease course, with indolent and aggressive subtypes now well recognised. Indolent MCL is often characterised by a leukaemic presentation, SOX11 negativity and low proliferation index (Ki-67). Aggressive MCL is characterised by rapid onset widespread lymphadenopathy, extra-nodal involvement, blastoid or pleomorphic histology and high Ki-67. Tumour protein p53 (TP53) aberrations in aggressive MCL are recognised with clear negative impact on survival. Until recently, trials have not addressed these specific subtypes separately. With the increasing availability of targeted novel agents and cellular therapies, the treatment landscape is constantly evolving. In this review, we describe the clinical presentation, biological factors, and specific management considerations of both indolent and aggressive MCL and discuss current and potential future evidence which may help move to a more personalised approach.

Personalized approaches for treatment-naïve mantle cell lymphoma

INTRODUCTION

Mantle cell lymphoma (MCL) can have diverse disease presentations, which vary in aggressiveness and prognosis, and can occur in patients with varying ability to tolerate therapy. Additionally, the options for treatment of MCL have expanded rapidly in the last decade, translating to improved outcome for patients.

AREAS COVERED

We review the initial evaluation of patients with MCL, identifying disease- and patient-specific prognostic factors, along with personalized therapies for patients with MCL. Specific scenarios include indolent and limited-stage MCL, advanced-stage disease in transplant-eligible and ineligible patients, and high-risk TP53 mutant disease. Ongoing trials and future directions in MCL treatment are also highlighted.

EXPERT OPINION

Given the wide array of disease and patient presentations with MCL, a personalized therapeutic approach is needed to optimize outcomes. The best therapeutic strategy should incorporate disease prognostic factors, patient status and comorbidities, goals of care, and response to treatment.

Tumorigenic role of Musashi-2 in aggressive mantle cell lymphoma

SOX11 overexpression has been associated with aggressive behavior of mantle cell lymphomas (MCL). SOX11 is overexpressed in embryonic and cancer stem cells (CSC) of some tumors. Although CSC have been isolated from primary MCL, their relationship to SOX11 expression and contribution to MCL pathogenesis and clinical evolution remain unknown. Here, we observed enrichment in leukemic and hematopoietic stem cells gene signatures in SOX11+ compared to SOX11- MCL primary cases. Musashi-2 (MSI2) emerged as one of the most significant upregulated stem cell-related genes in SOX11+ MCLs. SOX11 is directly bound to the MSI2 promoter upregulating its expression in vitro. MSI2 intronic enhancers were strongly activated in SOX11+ MCL cell lines and primary cases. MSI2 upregulation was significantly associated with poor overall survival independently of other high-risk features of MCL. MSI2 knockdown decreased the expression of genes related to apoptosis and stem cell features and significantly reduced clonogenic growth, tumor cell survival and chemoresistance in MCL cells. MSI2-knockdown cells had reduced tumorigenic engraftment into mice bone marrow and spleen compared to control cells in xenotransplanted mouse models. Our results suggest that MSI2 might play a key role in sustaining stemness and tumor cell survival, representing a possible novel target for therapeutic interventions in MCL.

Survival of patients with mantle cell lymphoma in the rituximab era: Retrospective binational analysis between 2000 and 2020

Mantle cell lymphoma (MCL) is a rare peripheral B-cell lymphoma characterised by eventual relapse and progression towards a more aggressive disease biology. With the introduction of rituximab- and cytarabine-based immunochemotherapy regimens, the prognosis of the disease has changed dramatically over the last two decades. To assess the real-world survival of patients with MCL, we used a population-based cohort of 564 patients with MCL who were diagnosed and treated between 2000 and 2020. Patient data were collected from seven Finnish treatment centres and one Spanish treatment centre. For the entire patient population, we report a 2-year overall survival (OS) rate of 77%, a 5-year OS of 58%, and a 10-year OS of 32%. The estimated median OS was 80 months after diagnosis. MCL is associated with increased mortality across the entire patient population. Additionally, we assessed the survival of patients after MCL relapse with the aim of establishing a cut-off point of prognostic significance. Based on our statistical analysis of survival after the first relapse, disease progression within 24 months of the initial diagnosis should be considered as a strong indicator of poor prognosis.

Genomic landscape of mature B-cell non-Hodgkin lymphomas - an appraisal from lymphomagenesis to drug resistance

BACKGROUND

Mature B-cell non-Hodgkin lymphomas are one of the most common hematological malignancies with a divergent clinical presentation, phenotype, and course of disease regulated by underlying genetic mechanism.

MAIN BODY

Genetic and molecular alterations are not only critical for lymphomagenesis but also largely responsible for differing therapeutic response in these neoplasms. In recent years, advanced molecular tools have provided a deeper understanding regarding these oncogenic drives for predicting progression as well as refractory behavior in these diseases. The prognostic models based on gene expression profiling have also been proved effective in various clinical scenarios. However, considerable overlap does exist between the genotypes of individual lymphomas and at the same time where additional molecular lesions may be associated with each entity apart from the key genetic event. Therefore, genomics is one of the cornerstones in the multimodality approach essential for classification and risk stratification of B-cell non-Hodgkin lymphomas.

CONCLUSION

We hereby in this review discuss the wide range of genetic aberrancies associated with tumorigenesis, immune escape, and chemoresistance in major B-cell non-Hodgkin lymphomas.

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.;

Combined epigenetic and immunotherapy for blastic and classical mantle cell lymphoma

Classical MCL (cMCL) constitutes 6-8% of all B cell NHL. Despite recent advances, MCL is incurable except with allogeneic stem cell transplant. Blastic mantle cell lymphoma (bMCL) is a rarer subtype of cMCL associated with an aggressive clinical course and poor treatment response, frequent relapse and poor outcomes. We treated 13 bMCL patients with combined epigenetic and immunotherapy treatment consisting of vorinostat, cladribine and rituximab (SCR). We report an increased OS greater than 40 months with several patients maintaining durable remissions without relapse for longer than 5 years. This is remarkably better then current treatment regimens which in bMCL range from 14.5-24 months with conventional chemotherapy regimens. We demonstrate that the G/A870 CCND1 polymorphism is predictive of blastic disease, nuclear localization of cyclinD1 and response to SCR therapy. The major resistance mechanisms to SCR therapy are loss of CD20 expression and evasion of treatment by sanctuary in the CNS. These data indicate that administration of epigenetic agents improves efficacy of anti-CD20 immunotherapies. This approach is promising in the treatment of MCL and potentially other previously treatment refractory cancers.

Symptomatic Thyroglossal Duct Cyst Presenting With Synchronous and Localized Tongue Base Extranodal Mantle Cell Lymphoma. A Unique Case Report Demonstrating Lymphoma Colonization of Cyst Wall, Potentially Relating to a Persistent Embryological Foramen Cecum Remnant

A 77-year-old male presented with a progressively enlarging midline neck mass. On further investigation he was found to have synchronous thyroglossal duct cyst and extranodal mantle cell lymphoma (MCL) localized to the base of tongue. Both pathologies were managed simultaneously with a surgical approach and the patient remained in clinical remission at the time of publication without indication for systemic oncological treatment. Histology revealed primary extranodal nonblastoid MCL forming a base of tongue mass, with colonization of the thyroglossal duct cyst. Lymphoma was also found in the epithelium of a crypt-like tract traversing one of the tongue base tumor sections. This tract was anatomically and histologically consistent with documented descriptions of the foramen cecum. This case report illustrates a previously undescribed temporal, clinical, and histological association between a base of tongue MCL and symptomatic thyroglossal duct cyst. We provide evidence for a potential causal relationship for the presentation of the thyroglossal duct cyst as a result of oropharyngeal MCL, in the absence of clinical and histological evidence of disseminated disease, directly infiltrating from its tongue base origin to the infrahyoid neck region, potentially via an embryologic foramen cecum remnant. We also highlight the crucial role of the histopathologist in multidisciplinary clinicopathological discussion in demonstrating how fundamental embryological and microanatomical relationships can unite apparently separate diseases.

Genomic and transcriptomic profiling reveals distinct molecular subsets associated with outcomes in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a phenotypically and genetically heterogeneous malignancy in which the genetic alterations determining clinical indications are not fully understood. Here, we performed a comprehensive whole-exome sequencing analysis of 152 primary samples derived from 134 MCL patients, including longitudinal samples from 16 patients and matched RNA-Seq data from 48 samples. We classified MCL into 4 robust clusters (C1-C4). C1 featured mutated immunoglobulin heavy variable (IGHV), CCND1 mutation, amp(11q13), and active B cell receptor (BCR) signaling. C2 was enriched with del(11q)/ATM mutations and upregulation of NF-κB and DNA repair pathways. C3 was characterized by mutations in SP140, NOTCH1, and NSD2, with downregulation of BCR signaling and MYC targets. C4 harbored del(17p)/TP53 mutations, del(13q), and del(9p), and active MYC pathway and hyperproliferation signatures. Patients in these 4 clusters had distinct outcomes (5-year overall survival [OS] rates for C1-C4 were 100%, 56.7%, 48.7%, and 14.2%, respectively). We also inferred the temporal order of genetic events and studied clonal evolution of 16 patients before treatment and at progression/relapse. Eleven of these samples showed drastic clonal evolution that was associated with inferior survival, while the other samples showed modest or no evolution. Our study thus identifies genetic subsets that clinically define this malignancy and delineates clonal evolution patterns and their impact on clinical outcomes.

Current Knowledge in Genetics, Molecular Diagnostic Tools, and Treatments for Mantle Cell Lymphomas

Mantle Cell lymphoma (MCL) is a mature B-cell lymphoma with a well-known hallmark genetic alteration in most cases, t (11,14)(q13q32)/CCND1-IGH. However, our understanding of the genetic and epigenetic alterations in MCL has evolved over the years, and it is now known that translocations involving CCND2, or cryptic insertion of enhancer elements of IGK or IGL gene, can also lead to MCL. On a molecular level, MCL can be broadly classified into two subtypes, conventional MCL (cMCL) and non-nodal MCL (nnMCL), each with different postulated tumor cell origin, clinical presentation and behavior, mutational pattern as well as genomic complexity. This article reviews both the common and rare alterations in MCL on a gene mutational, chromosomal arm, and epigenetic level, in the context of their contribution to the lymphomagenesis and disease evolution in MCL. This article also summarizes the important prognostic factors, molecular diagnostic tools, and treatment options based on the most recent MCL literature.

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.

CD5-negative mantle cell lymphoma: clinicopathologic features of an indolent variant that confers a survival advantage

Conventionally, mantle cell lymphoma (MCL) is an aggressive CD5-positive B-cell malignancy with poor prognosis and limited survival. However, a small subset of patients presents with indolent disease and can be managed on a 'watch and wait' approach. CD5-negative MCL has recently been recognized as a more favorable variant of MCL, but its clinical and biological implications remain ill-defined. We performed the most extensive review to-date of all reported cases of CD5-negative MCL and included unpublished cases diagnosed at our institutions to further characterize this disease subset. Based on our analysis of 356 cases of CD5-negative MCL, we conclude that median overall survival exceeds 14 years and is independent of favorable prognostic markers such as leukemic non-nodal disease, absence of SOX11, and low Ki-67.

How to Diagnose and Treat CD5-Positive Lymphomas Involving the Spleen

Patients with CD5-expressing lymphomas presenting with splenomegaly are frequently diagnosed with chronic lymphocytic leukemia. The most important differential diagnosis is mantle cell lymphoma, both in its classical and leukemic, non-nodal forms, given its prognostic and therapeutic implications. Other small B-cell neoplasms that frequently involve the spleen and occasionally express CD5 include the splenic marginal zone lymphoma, hairy cell leukemia and, rarely, lymphoplasmacytic lymphoma. The frequency of CD5 positivity depends in part on the sensitivity of the detection methods employed. Usually, a combination of morphological, immunophenotypic and molecular findings allows for a precise sub-classification of CD5-positive, low-grade B-cell lymphomas of the spleen. Some of these tumors may display a mixture of small and larger B cells, raising the possibility of more aggressive lymphomas, such as diffuse large B-cell lymphomas (DLBCL). Approximately 5-10% of DLBCL are CD5-positive and some may manifest as primary splenic lesions. When available, the morphology of DLBCL in the splenic tissue is distinctive and a leukemic picture is very rare. In conclusion, the appropriate morphological and clinical context assisted by flow cytometry panels and/or immunohistochemistry allows the differential diagnosis of CD5-positive, non-Hodgkin, B-cell lymphomas involving the spleen.

Mantle Cell Lymphoma with Chronic Lymphocytic Leukemia-Like Features: A Diagnostic Mimic and Pitfall

Mantle cell lymphoma (MCL) is a mature B-cell neoplasm characterized by t(11;14)(q13;q32) and cyclin D1 overexpression in >95% of cases. Classic MCL cases are composed of a monotonous population of small to medium-sized lymphocytes with irregular nuclear contours that are positive for cyclin D1 and SOX11, and negative for CD23 and CD200. By contrast, occasional MCL cases express CD23 and CD200 but lack of SOX11, and morphologically and immunophenotypically resemble chronic lymphocytic leukemia (CLL), termed as CLL-like MCL in this study. These neoplasms pose a diagnostic challenge and easy to be diagnosed as CLL in daily practice. We studied 14 cases of CLL-like MCL to define their clinicopathologic features and compared them with 33 traditional CLL cases. There were 8 men and 6 women with a median age of 62 years (range, 44-80). Compared with CLL, patients with CLL-like MCL have lower levels of peripheral blood and bone marrow involvement, and more frequently had mutated IGHV. Immunophenotypically, CLL-like MCL often showed moderate to bright expression of B-cell antigens and surface immunoglobulin light chain, dim and partial expression of CD23 and CD200, infrequent CD43 positivity, and lack of LEF1. The overall survival of patients with CLL-like MCL was similar to that of CLL patients. In conclusion, CD23+, CD200+, and SOX11-negative MCL closely resemble CLL, both clinically and pathologically, including a similar indolent clinical course. They may pose a diagnostic challenge. However, patients with CLL-like MCL also have distinctive immunophenotypic features that are useful to distinguish these neoplasms from CLL.

Cyclin D2 overexpression drives B1a-derived MCL-like lymphoma in mice

Mantle cell lymphoma (MCL) is an aggressive B cell lymphoma with poor long-term overall survival. Currently, MCL research and development of potential cures is hampered by the lack of good in vivo models. MCL is characterized by recurrent translocations of CCND1 or CCND2, resulting in overexpression of the cell cycle regulators cyclin D1 or D2, respectively. Here, we show, for the first time, that hematopoiesis-specific activation of cyclin D2 is sufficient to drive murine MCL-like lymphoma development. Furthermore, we demonstrate that cyclin D2 overexpression can synergize with loss of p53 to form aggressive and transplantable MCL-like lymphomas. Strikingly, cyclin D2-driven lymphomas display transcriptional, immunophenotypic, and functional similarities with B1a B cells. These MCL-like lymphomas have B1a-specific B cell receptors (BCRs), show elevated BCR and NF-κB pathway activation, and display increased MALT1 protease activity. Finally, we provide preclinical evidence that inhibition of MALT1 protease activity, which is essential for the development of early life-derived B1a cells, can be an effective therapeutic strategy to treat MCL.

Detailed characterization of the transcriptome of single B cells in mantle cell lymphoma suggesting a potential use for SOX4

Mantle cell lymphoma (MCL) is a malignancy arising from naive B lymphocytes with common bone marrow (BM) involvement. Although t(11;14) is a primary event in MCL development, the highly diverse molecular etiology and causal genomic events are still being explored. We investigated the transcriptome of CD19⁺ BM cells from eight MCL patients at single-cell level. The transcriptomes revealed marked heterogeneity across patients, while general homogeneity and clonal continuity was observed within the patients with no clear evidence of subclonal involvement. All patients were SOX11⁺CCND1⁺CD20⁺. Despite monotypic surface immunoglobulin (Ig) κ or λ protein expression in MCL, 10.9% of the SOX11 + malignant cells expressed both light chain transcripts. The early lymphocyte transcription factor SOX4 was expressed in a fraction of SOX11 + cells in two patients and co-expressed with the precursor lymphoblastic marker, FAT1, in a blastoid case, suggesting a potential prognostic role. Additionally, SOX4 was found to identify non-malignant SOX11^– pro-/pre-B cell populations. Altogether, the observed expression of markers such as SOX4, CD27, IgA and IgG in the SOX11⁺ MCL cells, may suggest that the malignant cells are not fixed in the differentiation state of naïve mature B cells, but instead the patients carry B lymphocytes of different differentiation stages.

Non-chemotherapy Options for Newly Diagnosed Mantle Cell Lymphoma

OPINION STATEMENT

Mantle cell lymphoma is a rare and incurable non-Hodgkin lymphoma with a heterogenous clinical presentation. Typically, treatment consists of frontline chemoimmunotherapy induction with or without autologous stem cell transplant (ASCT) as consolidation. However, this approach has the propensity to increase short- and long-term toxicities, such as secondary malignancies, without being curative. Genomic profiling of MCL will allow for greater impact of new targeted therapies in the future and may become a helpful tool to guide treatment. Based on the data discussed, use of non-chemotherapy options may become the preferred approach for frontline therapy as opposed to conventional chemotherapy and hematopoietic stem cell transplants.

Clinicopathological and Immunohistochemical Profile of Mantle Cell Lymphoma: An Institutional Experience

Introduction

Mantle cell lymphoma (MCL) is a biologically aggressive B-cell non-Hodgkin lymphoma (NHL) with distinctive morphologic, immunophenotypic, and molecular characteristics. Differentiation from other chronic lymphoproliferative disorders is essential for prognostication.

Aim

This paper aims to study the clinicopathological features of MCL with emphasis on immunohistochemical features and disease correlation.

Method

To do so, clinicopathological characteristics from 21 cases of MCL (14 males, seven females, M:F=2:1) diagnosed in the last five years i.e. 2015 to 2020, were retrospectively reviewed and correlated with immunohistochemistry (IHC) data. Particularly those pertaining to cyclin D1, SRY-box transcription factor 11 (SOX11), cluster of differentiation (CD) 5, CD23, MIB E3 ubiquitin protein ligase 1 (MIB1), tumor protein 53 (TP53), c-myelocytomatosis oncogene product (c-MYC), multiple myeloma oncogene 1 (MUM1), mouse double minute 2 homolog (MDM2), and Epstein-Barr virus latent membrane protein 1 (EBV-LMP1) expression with its aberrations.

Observations

This study shows that MCL constituted 4.2% (21/500) of all NHLs with a mean age of 57.5 years (median 60 years, range 30 to 80 years). The disease was nodal in 19, and extranodal in the remaining two cases. 14 of 21 (67%) had generalized lymphadenopathy and 71% had bone marrow (BM) involvement. The nodal involvement was diffuse in 9/17 (53%), 8/21 (38%) had a blastoid morphology, and an in-situ MCL pattern was not seen in any of the cases selected for the study. Cyclin D1 immunoexpression correlated well with SOX11; CD5-negative in five cases; and CD23-positive in three cases. TP53 and c-MYC expression were noted in 17/19 (89.4%) and 8/17 (47%), respectively. MUM1 registered positive in six cases. None of the cases showed immunopositivity for MDM2 and EBV-LMP1.

Conclusion

In essence, this study indicates that morphological and immunophenotypic subclassification of mantle cell lymphoma with a wider panel of IHC markers is essential for understanding disease biology and better prognostication.

SOX11 Inhibitors Are Cytotoxic in Mantle Cell Lymphoma

PURPOSE

Mantle cell lymphoma (MCL) is a fatal subtype of non-Hodgkin lymphoma. SOX11 transcription factor is overexpressed in the majority of nodal MCL. We have previously reported that B cell-specific overexpression of SOX11 promotes MCL pathogenesis via critically increasing BCR signaling in vivo. SOX11 is an attractive target for MCL therapy; however, no small-molecule inhibitor of SOX11 has been identified to date. Although transcription factors are generally considered undruggable, the ability of SOX11 to bind to the minor groove of DNA led us to hypothesize that there may exist cavities at the protein-DNA interface that are amenable to targeting by small molecules.

EXPERIMENTAL DESIGN

Using a combination of in silico predictions and experimental validations, we report here the discovery of three structurally related compounds (SOX11i) that bind SOX11, perturb its interaction with DNA, and effect SOX11-specific anti-MCL cytotoxicity.

RESULTS

We find mechanistic validation of on-target activity of these SOX11i in the inhibition of BCR signaling and the transcriptional modulation of SOX11 target genes, specifically, in SOX11-expressing MCL cells. One of the three SOX11i exhibits relatively superior in vitro activity and displays cytotoxic synergy with ibrutinib in SOX11-expressing MCL cells. Importantly, this SOX11i induces cytotoxicity specifically in SOX11-positive ibrutinib-resistant MCL patient samples and inhibits Bruton tyrosine kinase phosphorylation in a xenograft mouse model derived from one of these subjects.

CONCLUSIONS

Taken together, our results provide a foundation for therapeutically targeting SOX11 in MCL by a novel class of small molecules.

Advances in Classification and Treatment of Non-Hodgkin Lymphoma: Mantle Cell

Mantle cell lymphoma is a rare, aggressive, and largely incurable form of non-Hodgkin lymphoma. There are a number of well-characterized prognostic features but nothing that can help guide therapy. Treatment with chemotherapy is generally effective in the short term, but relapse is inevitable and subsequent treatment is challenging. The use of Bruton tyrosine kinase inhibitors, however, has transformed practice. These agents are highly active in relapsed disease and are very well-tolerated drugs. Chemotherapy-free combinations using Bruton tyrosine kinase inhibitors look very exciting and will likely evolve to be part of frontline care in the future.

Multiple primary tumor of hematopoietic tissue: myeloid sarcoma in combination with mantle cell lymphoma. Case report

The prevalence of multiple primary tumors has significantly increased last time. The question of choosing the optimal tactics of therapy today not fully resolved. Particular interest is the simultaneous detection of two neoplasms of similar origin in one study biopsy material. This publication presents a case of simultaneous diagnosis of myeloid sarcoma and mantle cell lymphoma in a 65-year-old patient, which required use of two different chemotherapy protocols. This example shows the need to use an extended diagnostic approach at all stages of the therapy, which allows choosing right tactics of therapy and achieving complete remission of two neoplasms.

Leukemic Variant of Mantle Cell Lymphoma: Clinical Presentation and Management

PURPOSE OF REVIEW

This review summarizes the unique presentation and management of the leukemic variant of mantle cell lymphoma (LV-MCL, also referred to as non-nodal MCL) and highlights the biologic and clinical differentiation from classical mantle cell lymphoma (cMCL) in biomarker expression, clinical features, prognosis, disease course, and treatment.

RECENT FINDINGS

Several studies have evaluated the gene expression profile of mantle cell lymphoma, differentiating LV-MCL from cMCL. The typical immunophenotypic profile is CD5-positive, SOX 11-negative, CD23-low, CD200-low, and cyclin D1 overexpressed. LV-MCL commonly has mutated immunoglobulin heavy chain variable region genes. Data on treatment of LV-MCL is limited to retrospective analyses; the ideal treatment for these patients is unknown although many have a clinically indolent, asymptomatic presentation and often may be observed for an extended period without active treatment. LV-MCL is a clinically and biologically distinct entity. Clinically, it must be distinguished from chronic lymphocytic leukemia and cMCL. Future prospective, randomized clinical trials are required to optimize management, define the initial treatment, and appropriately sequence treatment modalities.

Progress in molecular feature of smoldering mantle cell lymphoma

Mantle cell lymphoma (MCL) is considered one of the most aggressive lymphoid tumors. However, it sometimes displays indolent behavior in patients and might not necessitate treatment at diagnosis; this has been described as "smoldering MCL" (SMCL). There are significant differences in the diagnosis, prognosis, molecular mechanisms and treatments of indolent MCL and classical MCL. In this review, we discuss the progress in understanding the molecular mechanism of indolent MCL to provide insights into the genomic nature of this entity. Reported findings of molecular features of indolent MCL include a low Ki-67 index, CD200 positivity, a low frequency of mutations in TP53, a lack of SOX11, normal arrangement and expression of MYC, IGHV mutations, differences from classical MCL by L-MCL16 assays and MCL35 assays, an unmutated P16 status, few defects in ATM, no NOTCH1/2 mutation, Amp 11q gene mutation, no chr9 deletion, microRNA upregulation/downregulation, and low expression of several genes that have been valued in recent years (SPEN, SMARCA4, RANBP2, KMT2C, NSD2, CARD11, FBXW7, BIRC3, KMT2D, CELSR3, TRAF2, MAP3K14, HNRNPH1, Del 9p and/or Del 9q, SP140 and PCDH10). Based on the above molecular characteristics, we may distinguish indolent MCL from classical MCL. If so, indolent MCL will not be overtreated, whereas the treatment of classical MCL will not be delayed.

SOX11, CD70 and Treg cells configure the tumor immune microenvironment of aggressive mantle cell lymphoma

Mantle cell lymphoma (MCL) is a mature B-cell neoplasm with a heterogeneous clinical and biological behavior. SOX11 oncogenic expression contributes to the aggressiveness of these tumors by different mechanisms including tumor and stromal cell interactions. However, the precise composition of the immune cell microenvironment of MCL, its possible relationship to SOX11 expression, and how it may contribute to tumor behavior is not well known. Here, we performed an integrative transcriptome analysis of 730 immune-related genes combined with the immune cell phenotype analysis by immunohistochemistry in SOX11+ and SOX11- primary nodal MCL cases and non-neoplastic reactive lymph nodes (RLN). SOX11+ MCL had a significant lower T-cell intratumoral infiltration compared to negative cases. A reduced expression of MHCI/II-like and T-cell costimulation and signaling activation related transcripts was significantly associated with poor clinical outcome. Moreover, we identified CD70 as a SOX11 direct target gene, whose overexpression was induced in SOX11+ but not SOX11- tumor cells by CD40L in vitro. CD70 was overexpressed in primary SOX11+ MCL and it was associated with an immune unbalance of the tumor microenvironment characterized by increased number of effector Treg cell infiltration, higher proliferation, and aggressive clinical course. CD27 was expressed with moderate to strong intensity in 76% of cases. Overall, our results suggest that SOX11 expression in MCL is associated with an immunosuppressive microenvironment characterized by CD70 overexpression in tumor cells, increased Treg cell infiltration and downmodulation of antigen-processing and -presentation and T-cell activation that could promote MCL progression and represent a potential target for tailored therapies.

Intensive induction regimens after deferring initial therapy for mantle cell lymphoma are not associated with improved survival

INTRODUCTION

While most patients with mantle cell lymphoma (MCL) receive therapy shortly after diagnosis, a subset of patients with indolent-behaving disease can safely defer treatment. In this subgroup, we evaluated the importance of treatment intensity in patients with MCL who defer initial therapy.

METHODS

Out of 1134 patients with MCL from 12 academic centers, we analyzed 219 patients who initiated therapy at least 90 days after diagnosis. Patients who received induction with high-dose cytarabine and/or autologous stem cell transplantation (ASCT) in first remission were considered to have received intensive therapy (n = 88) while all other approaches were non-intensive (n = 131).

RESULTS

There was no difference in progression-free (PFS; P = .224) or overall survival (OS; P = .167) in deferred patients who received non-intensive vs. intensive therapy. Additionally, univariate and multivariate Cox proportional hazards models were performed for PFS and OS. Treatment at an academic center (HR 0.43, P = .015) was associated with improved OS in both univariate and multivariate models, while intensity of treatment was not associated with improved OS in either model.

CONCLUSIONS

These results indicate that intensified initial treatment is not associated with improved survival after deferring initial therapy, although prospective studies are needed to determine which of these patients with MCL may benefit from intensive therapy.

Mantle cell lymphoma-Advances in molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterized by its heterogenous behavior with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with very limited prognosis. A better understanding of the complex biology of MCL has already led to the approval of several innovative agents, expanding the landscape of MCL therapies and improving therapeutic options especially for refractory or relapsed disease. Nevertheless, to further optimize MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated in clinical patient management. This review highlights recent advances in deciphering the molecular background of MCL, the definition of prognostically relevant factors and the identification of potential druggable targets and summarizes current treatment recommendations for primary and relapsed/refractory MCL including novel targeted therapies.

Prognostic significance of p53, Sox11, and Pax5 co-expression in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a relatively rare subtype of non-Hodgkin’s lymphoma. To identify molecular biomarkers in MCL, we performed immunohistochemistry tissue arrays using biopsies from 64 MCL patients diagnosed in West China Hospital from 2012 to 2016. TP53 mutation status in those patients was also examined by sequencing. The sequencing results showed TP53 mutations were highly heterogeneous in MCL. We identified four novel TP53 mutations in MCL: P151R, G199R, V218E, and G325R. The MCL patients with TP53 mutations had inferior progression-free survival (PFS, p = 0.002) and overall survival (OS, p = 0.011). Tissue array results showed the expression of p53, Sox11, or Pax5 alone did not correlate with the patient PFS and OS. However, the MCL patients with triple-positive expression of p53/Sox11/Pax5 had inferior PFS (p = 0.008) and OS (p = 0.002). Such risk stratification was independent to the mantle cell lymphoma international prognostic index (MIPI), Ki-67 value, and TP53 mutation status of the patients. The triple-positive patients might represent a subtype of high-risk MCL. Our findings might indicate a novel way to stratify MCL and predict patients’ prognosis.

Extremely Rare Primary Spinal Epidural Indolent Mantle Cell Lymphoma: A Case Report With Literature Review

Lymphomas are malignant tumors arising from lymphoid tissues and can spread to other organs. Primary extra-nodal locations such as the spinal epidural space are less common. Primary spinal epidural lymphoma (PSEL), which can be either Hodgkin’s or non-Hodgkin’s type, is rare. There are different cell types of Non-Hodgkin’s PSEL, among which mantle cell lymphoma (MCL) is extremely rare. MCL can have an aggressive or indolent course. Indolent MCL in the epidural space is not yet reported. We report a case of 20-year-old male who presented with radiating low back pain for six weeks followed by a progressive neurological deficit in both lower limbs for nine days. Magnetic resonance imaging (MRI) revealed spinal epidural tumor extending from L2 to L3. Decompression and subtotal excision biopsy were performed. Histopathology and immunohistochemistry identified indolent MCL. His neurological status improved to normal postoperatively, and he was referred to an oncologist. He is under observation and planned for radiotherapy. At one-year follow-up, he is asymptomatic and doing his regular job abroad.

Mantle cell lymphoma - advances in molecular biology, prognostication and treatment approaches

Mantle cell lymphoma (MCL) is clinically characterised by its heterogenous behaviour with courses ranging from indolent cases that do not require therapy for years to highly aggressive MCL with a very limited prognosis. A better understanding of the complex biology of MCL has already led to the approval of several innovative agents, expanding the landscape of MCL therapies and improving therapeutic options especially for refractory/relapsed (R/R) disease. Nevertheless, to further optimise MCL treatment, early identification of individual risk profile and risk-adapted, patient-tailored choice of therapeutic strategy needs to be prospectively incorporated into clinical patient management. The present review highlights recent advances in deciphering the molecular background of MCL, the definition of prognostically relevant factors and the identification of potential druggable targets and summarises current treatment recommendations for primary and R/R MCL including novel targeted therapies.

CD5-negative blastoid variant mantle cell lymphoma: a diagnostic dilemma

We encountered two cases of CD5^- blastoid variant mantle cell lymphoma (MCL), prompting us to investigate the proportion of CD5 negativity in MCL and assess the diagnosis of aggressive MCL variants. Among 117 patients diagnosed with MCL, CD5 negativity was observed in 13% (13/104) of cases with classical MCL and 15% (2/13) of cases with blastoid/pleomorphic variant MCL. Of the aggressive MCL variant cases, tumor cells exhibited intermediate nuclear size and required differential diagnosis between blastoid variant and classical MCL in six patients, and classical MCL cells were found in the background of aggressive variant tumors or in other sites in six patients. Of 1534 patients with diffuse large B-cell lymphoma (DLBCL), CD5 positivity was observed in 8% (121/1534) of cases. Immunohistochemical staining for cyclin D1 performed for these cases revealed one cyclin D1-positive and IGH/CCND1 fusion-positive case (0.9%, 1/114), namely pleomorphic variant MCL. Of the remaining 1413 patients initially diagnosed with CD5^- DLBCL, the diagnoses of two patients (0.1%) were amended to CD5^- blastoid variant MCL in the relapse phase based on morphology, cyclin D1 immunostaining, and fluorescence in situ hybridization. The incidence of CD5 negativity was similar between classical MCL and two aggressive variants. Accurate diagnosis of MCL variants was enabled by identifying a classical MCL component and/or CD5 positivity; however, we misdiagnosed two cases of CD5^- blastoid variant MCL. A small number of MCL variants may be included in CD5^- DLBCL cases. The diagnosis of CD5^- aggressive variant MCL remains challenging but crucial because of its therapeutic significance.

Single nucleotide variants in immune-response genes and the tumor microenvironment composition predict progression of mantle cell lymphoma

Background

There is evidence to consider that the tumor microenvironment (TME) composition associates with antitumor immune response, and may predict the outcome of various non-Hodgkin lymphoma subtypes. However, in the case of mantle cell lymphoma (MCL), a rare and aggressive disease, there is lacking a detailed study of the TME components, as well as an integrative approach among them in patients’ samples. Also, from the genetic point of view, it is known that single nucleotide variants (SNVs) in immune-response genes are among important regulators of immunity. At present, it is uncertain whether SNVs in candidate immune-response genes and the TME composition are able to alter the prognosis in MCL.

Methods

We assessed a detailed TME composition in 88 MCL biopsies using immunohistochemistry, which was automatically analyzed by pixel counting (Aperio system). We also genotyped SNVs located in candidate immune-response genes (IL12A, IL2, IL10, TGFB1, TGFBR1, TGFBR2, IL17A, IL17F) in 95 MCL patients. We tested whether the SNVs could modulate the respective protein expression and TME composition in the tumor compartment. Finally, we proposed survival models in rituximab-treated patients, considering immunohistochemical and SNV models.

Results

High FOXP3/CD3 ratios (p = 0.001), high IL17A levels (p = 0.003) and low IL2 levels (p = 0.03) were individual immunohistochemical predictors of poorer survival. A principal component, comprising high quantities of macrophages and high Ki-67 index, also worsened outcome (p = 0.02). In the SNV model, the CC haplotype of IL10 (p < 0.01), the GG genotype of IL2 rs2069762 (p = 0.02) and the AA+AG genotypes of TGFBR2 rs3087465 (p < 0.01) were independent predictors of outcome. Finally, the GG genotype of TGFB1 rs6957 associated with lower tumor TGFβ levels (p = 0.03) and less CD163+ macrophages (p = 0.01), but did not modulate patients’ survival.

Conclusions

Our results indicate that the TME composition has relevant biological roles in MCL. In this setting, immunohistochemical detection of T-reg cells, IL17A and IL2, coupled with SNV genotyping in IL10, TGFBR2 and IL2, may represent novel prognostic factors in this disease, following future validations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07891-9.

Time-Resolved scRNA-Seq Tracks the Adaptation of a Sensitive MCL Cell Line to Ibrutinib Treatment

Since the approval of ibrutinib for relapsed/refractory mantle cell lymphoma (MCL), the treatment of this rare mature B-cell neoplasm has taken a great leap forward. Despite promising efficacy of the Bruton tyrosine kinase inhibitor, resistance arises inevitably and the underlying mechanisms remain to be elucidated. Here, we aimed to decipher the response of a sensitive MCL cell line treated with ibrutinib using time-resolved single-cell RNA sequencing. The analysis uncovered five subpopulations and their individual responses to the treatment. The effects on the B cell receptor pathway, cell cycle, surface antigen expression, and metabolism were revealed by the computational analysis and were validated by molecular biological methods. The observed upregulation of B cell receptor signaling, crosstalk with the microenvironment, upregulation of CD52, and metabolic reprogramming towards dependence on oxidative phosphorylation favor resistance to ibrutinib treatment. Targeting these cellular responses provide new therapy options in MCL.