Molecular features of hepatosplenic T-cell lymphoma unravels potential novel therapeutic targets

Hepatosplenic T-cell lymphoma displays an original oyster-shell cytological pattern and a genomic profile distinct from that of γδ T-cell large granular lymphocytic leukemia

Not available.

Biology and genetics of extranodal mature T-cell and NKcell lymphomas and lymphoproliferative disorders

The extranodal mature T-cell and NK-cell lymphomas and lymphoproliferative disorders represent a unique group of rare neoplasms with both overlapping and distinct clinicopathological, biological, and genomic features. Their predilection for specific sites, such as the gastrointestinal tract, aerodigestive tract, liver, spleen, and skin/soft tissues, underlies their classification. Recent genomic advances have furthered our understanding of the biology and pathogenesis of these diseases, which is critical for accurate diagnosis, prognostic assessment, and therapeutic decision-making. Here we review clinical, pathological, genomic, and biological features of the following extranodal mature T-cell and NK-cell lymphomas and lymphoproliferative disorders: primary intestinal T-cell and NK-cell neoplasms, hepatosplenic T-cell lymphoma, extranodal NK/T-cell lymphoma, nasal type, and subcutaneous panniculitis-like T-cell lymphoma.

Few and far between: clinical management of rare extranodal subtypes of mature T-cell and NK-cell lymphomas

While all peripheral T-cell lymphomas are uncommon, certain subtypes are truly rare, with less than a few hundred cases per year in the USA. There are often no dedicated clinical trials in these rare subtypes, and data are generally limited to case reports and retrospective case series. Therefore, clinical management is often based on this limited literature and extrapolation of data from the more common, nodal T-cell lymphomas in conjunction with personal experience. Nevertheless, thanks to tremendous pre-clinical efforts to understand these rare diseases, an increasing appreciation of the biological changes that underlie these entities is forming. In this review, we attempt to summarize the relevant literature regarding the initial management of certain rare subtypes, specifically subcutaneous panniculitis-like T-cell lymphoma, hepatosplenic T-cell lymphoma, intestinal T-cell lymphomas, and extranodal NK/T-cell lymphoma. While unequivocally established approaches in these diseases do not exist, we make cautious efforts to provide our approaches to clinical management when possible.

Role of cytokine in malignant T-cell metabolism and subsequent alternation in T-cell tumor microenvironment

T cells are an important component of adaptive immunity and T-cell-derived lymphomas are very complex due to many functional sub-types and functional elasticity of T-cells. As with other tumors, tissues specific factors are crucial in the development of T-cell lymphomas. In addition to neoplastic cells, T- cell lymphomas consist of a tumor micro-environment composed of normal cells and stroma. Numerous studies established the qualitative and quantitative differences between the tumor microenvironment and normal cell surroundings. Interaction between the various component of the tumor microenvironment is crucial since tumor cells can change the microenvironment and vice versa. In normal T-cell development, T-cells must respond to various stimulants deferentially and during these courses of adaptation. T-cells undergo various metabolic alterations. From the stage of quiescence to attention of fully active form T-cells undergoes various stage in terms of metabolic activity. Predominantly quiescent T-cells have ATP-generating metabolism while during the proliferative stage, their metabolism tilted towards the growth-promoting pathways. In addition to this, a functionally different subset of T-cells requires to activate the different metabolic pathways, and consequently, this regulation of the metabolic pathway control activation and function of T-cells. So, it is obvious that dynamic, and well-regulated metabolic pathways are important for the normal functioning of T-cells and their interaction with the microenvironment. There are various cell signaling mechanisms of metabolism are involved in this regulation and more and more studies have suggested the involvement of additional signaling in the development of the overall metabolic phenotype of T cells. These important signaling mediators include cytokines and hormones. The impact and role of these mediators especially the cytokines on the interplay between T-cell metabolism and the interaction of T-cells with their micro-environments in the context of T-cells lymphomas are discussed in this review article.

SOHO State of the Art Updates and Next Questions | Challenging Cases in Rare T-Cell Lymphomas

Mature T- and NK-cell neoplasms (MTNKN) collectively represent a rare disorder, representing less than 15% of all non-Hodgkin lymphoma (NHL) cases and qualifying for orphan disease designation by the U.S. Food and Drug Administration (FDA). These consist of 9 families in the fifth revised WHO classification of lymphoid neoplasms, which are made up of over 30 disease subtypes, underscoring the heterogeneity of clinical features, molecular biology, and genetics across this disease group. Moreover, the 5 most common subtypes (peripheral T-cell lymphoma, not otherwise specified; nodal TFH cell lymphoma, angioimmunoblastic type; extranodal NK-cell/T-cell lymphoma; adult T-cell leukemia/lymphoma; and ALK-positive or -negative anaplastic large cell lymphoma) comprise over 75% of MTNKN cases, so other subtypes are exceedingly rare in the context of all NHL diagnoses and consequently often lack consensus on best practices in diagnosis and management. In this review, we discuss the following entities-enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), hepatosplenic T-cell lymphoma (HSTCL), subcutaneous panniculitis-like T-cell lymphoma (SPTCL), and primary cutaneous ɣδ T-cell lymphoma (PCGD-TCL) - with an emphasis on clinical and diagnostic features and options for management.

The role of Vav3 expression for inflammation and cell death during experimental myocardial infarction

OBJECTIVES

Myocardial Infarction (MI) is the leading cause of chronic heart failure. Previous studies have suggested that Vav3, a receptor protein tyrosine kinase signal transducer, is associated with a variety of cellular signaling processes such as cell morphology regulation and cell transformation with oncogenic activity. However, the mechanism of Vav3-mediated MI development requires further investigation.

METHOD

Here, The authors established an MI rat model by ligating the anterior descending branch of the left coronary artery, and an MI cell model by treating cardiomyocytes with H2O2. Microarray analysis was conducted to identify genes with differential expression in heart tissues relevant to MI occurrence and development. Vav3 was thus selected for further investigation.

RESULTS

Vav3 downregulation was observed in MI heart tissue and H2O2-treated cardiomyocytes. Administration of Lentiviral Vav3 (LV-VAV3) in MI rats upregulated Vav3 expression in MI heart tissue. Restoration of Vav3 expression reduced infarct area and ameliorated cardiac function in MI rats. Cardiac inflammation, apoptosis, and upregulation of NFκB signal in heart tissue of MI animals were assessed using ELISA, TUNEL staining, real-time PCR, and WB. Vav3 overexpression reduced cardiac inflammation and apoptosis and inhibited NFκB expression and activation. Betulinic Acid (BA) was then used to re-activate NFκB in Vav3-overexpressed and H2O2-induced cardiomyocytes. The expression of P50 and P65, as well as nuclear P65, was significantly increased by BA exposure.

CONCLUSIONS

Vav3 might serve as a target to reduce ischemia damage by suppressing the inflammation and apoptosis of cardiomyocytes.

How molecular advances may improve the diagnosis and management of PTCL patients

Peripheral T-cell lymphomas (PTCL) comprised more than 30 rare heterogeneous entities, representing 10 to 15% of adult non-Hodgkin lymphomas. Although their diagnosis is still mainly based on clinical, pathological, and phenotypic features, molecular studies have allowed for a better understanding of the oncogenic mechanisms involved and the refinement of many PTCL entities in the recently updated classifications. The prognosis remains poor for most entities (5-year overall survival < 30%), with current conventional therapies based on anthracyclin-based polychemotherapy regimen, despite many years of clinical trials. The recent use of new targeted therapies appears to be promising for relapsed/refractory patients, such as demethylating agents in T-follicular helper (TFH) PTCL. However further studies are needed to evaluate the proper combination of these drugs in the setting of front-line therapy. In this review, we will summarize the oncogenic events for the main PTCL entities and report the molecular targets that have led to the development of new therapies. We will also discuss the development of innovative high throughput technologies that aid the routine workflow for the histopathological diagnosis and management of PTCL patients.

Single cell profiling of γδ hepatosplenic T-cell lymphoma unravels tumor cell heterogeneity associated with disease progression

PURPOSE

Hepatosplenic T-cell lymphoma (HSTCL), mostly derived from γδ T cells, is a rare but very aggressive lymphoma with poor outcomes. In this study, we generated the first single cell landscape for this rare disease and characterized the molecular pathogenesis underlying the disease progression.

METHODS

We performed paired single cell RNA-seq and T cell receptor (TCR) sequencing on biopsies from a HSTCL patient pre- and post- chemotherapy treatments. Following by a series of bioinformatics analysis, we investigated the gene expression profile of γδ HSTCS as well as its tumor microenvironment (TME).

RESULTS

We characterized the unique gene expressing signatures of malignant γδ T cells with a set of marker genes were newly identified in HSTCL (AREG, PLEKHA5, VCAM1 etc.). Although the malignant γδ T cells were expanded from a single TCR clonotype, they evolved into two transcriptionally distinct tumor subtypes during the disease progression. The Tumor_1 subtype was dominant in pre-treatment samples with highly aggressive phenotypes. While the Tumor_2 had relative mild cancer hallmark signatures but expressed genes associated with tumor survival signal and drug resistance (IL32, TOX2, AIF1, AKAP12, CD38 etc.), and eventually became the main tumor subtype post-treatment. We further dissected the tumor microenvironment and discovered the dynamically rewiring cell-cell interaction networks during the treatment. The tumor cells had reduced communications with the microenvironment post-treatment.

CONCLUSIONS

Our study reveals heterogenous and dynamic tumor and microenvironment underlying pathogenesis of HSTCL and may contribute to identify novel targets for diagnosis and treatment of HSTCL in the future.

Extranodal T- and NK-cell lymphomas

Non-cutaneous extranodal NK/T cell lymphoproliferations constitute a heterogenous group of rare neoplasms, occurring primarily in the gastro-intestinal tract, nasal area, spleen, and liver. Their nomenclature refers to their usual clinical presentation and predilection for specific anatomic sites-i.e. extranodal NK/T-cell lymphoma, nasal-type, hepatosplenic T-cell lymphoma, primary intestinal T-cell lymphomas, indolent lymphoproliferative disorders of the gastrointestinal tract, and breast implant-associated anaplastic large cell lymphoma. Extranodal tissues may also be involved by T-cell leukemias, or other entities usually presenting as nodal diseases. Primary extranodal entities range from indolent to highly aggressive diseases. Here, we will review the clinicopathologic features of the pertinent entities including the recent advances in their molecular and genetic characterization, with an emphasis on the changes introduced in the 2022 International Consensus Classification of lymphoid neoplasms, and highlight the diagnostic criteria helpful to sort out the distinction with potential mimickers.

Classification and challenges in the histopathological diagnosis of peripheral T-cell lymphomas, emphasis on the WHO-HAEM5 updates

Mature T-cell lymphomas represent neoplastic expansions of T-cell lymphocytes with a post-thymic derivation. Most of these tumors feature aggressive clinical behavior and challenging histopathological diagnosis and classification. Novel findings in the genomic landscape of T-cell lymphomas are helping to improve the understanding of the biology and the molecular mechanisms that underly its clinical behavior. The most recent WHO-HAEM5 classification of hematolymphoid tumors introduced novel molecular and histopathological findings that will aid in the diagnostic classification of this group of neoplasms. The current review article summarizes the most relevant diagnostic features of peripheral T-cell lymphomas with an emphasis on the updates that are incorporated at the WHO-HAEM5.

Hepatosplenic T-Cell Lymphoma Mimicking Acute Onset of Cholestatic Hepatitis in a Young Immunocompetent Man: A Case Report

We herein report a case of hepatosplenic T-cell lymphoma (HSTCL) incidentally found in a 30-year-old man who came to the emergency department after an ankle trauma. At admission, laboratory tests revealed abnormal liver enzymes and pancytopenia, and imaging showed mild hepatosplenomegaly. During hospitalization, the patient’s clinical condition worsened rapidly, with a concomitant increase in cholestatic enzymes, severe jaundice, and the worsening of pancytopenia. Causes of liver injury, including many infectious diseases, were explored until the diagnosis of HSTCL was made by liver and bone marrow biopsies. Subsequently, the patient underwent six cycles of chemotherapy with a CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone or prednisolone) regimen and one with Hyper-CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone) but, despite this aggressive treatment, died due to disease progression 2 months after diagnosis. This rare disease should be considered in the diagnostic workup of acute cholestatic hepatitis presenting with concomitant hepatosplenomegaly and cytopenia.

Monomorphic epitheliotropic intestinal T-cell lymphoma comprises morphologic and genomic heterogeneity impacting outcome

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare aggressive T-cell lymphoma most reported in Asia. We performed a comprehensive clinical, pathological and genomic study of 71 European MEITL patients (36 males, 35 females, median age 67 years). The majority presented with gastrointestinal involvement and had emergency surgery, and 40% had stage IV disease. The tumors were morphologically classified into two groups: typical (58%) and atypical (i.e., non-monomorphic or with necrosis, angiotropism or starry-sky pattern) (42%), sharing a homogeneous immunophenotypic profile (CD3+ [98%] CD4- [94%] CD5- [97%] CD7+ [97%] CD8+ [90%] CD56+ [86%] CD103+ [80%] cytotoxic marker+ [98%]) with more frequent expression of TCRgd (50%) than TCRab (32%). MYC expression (30% of cases) partly reflecting MYC gene locus alterations, correlated with non-monomorphic cytology. Almost all cases (97%) harbored deleterious mutation(s) and/or deletion of the SETD2 gene and 90% had defective H3K36 trimethylation. Other frequently mutated genes were STAT5B (57%), JAK3 (50%), TP53 (35%), JAK1 (12.5%), BCOR and ATM (11%). Both TP53 mutations and MYC expression correlated with atypical morphology. The median overall survival (OS) of 63 patients (43/63 only received chemotherapy after initial surgery) was 7.8 months. Multivariate analysis found a strong negative impact on outcome of MYC expression, TP53 mutation, STAT5B mutation and poor performance status while aberrant B-cell marker expression (20% of cases) correlated with better survival. In conclusion, MEITL is an aggressive disease with resistance to conventional therapy, predominantly characterized by driver gene alterations deregulating histone methylation and JAK/STAT signaling and encompasses genetic and morphologic variants associated with very high clinical risk.

Genetic profiling and biomarkers in peripheral T-cell lymphomas: current role in the diagnostic work-up

Peripheral T-cell lymphomas are a heterogeneous, and usually aggressive, group of mature T-cell neoplasms with overlapping clinical, morphologic and immunologic features. A large subset of these neoplasms remains unclassifiable with current diagnostic methods ("not otherwise specified"). Genetic profiling and other molecular tools have emerged as widely applied and transformative technologies for discerning the biology of lymphomas and other hematopoietic neoplasms. Although the application of these technologies to peripheral T-cell lymphomas has lagged behind B-cell lymphomas and other cancers, molecular profiling has provided novel prognostic and diagnostic markers as well as an opportunity to understand the biologic mechanisms involved in the pathogenesis of these neoplasms. Some biomarkers are more prevalent in specific T-cell lymphoma subsets and are being used currently in the diagnosis and/or risk stratification of patients with peripheral T-cell lymphomas. Other biomarkers, while promising, need to be validated in larger clinical studies. In this review, we present a summary of our current understanding of the molecular profiles of the major types of peripheral T-cell lymphoma. We particularly focus on the use of biomarkers, including those that can be detected by conventional immunohistochemical studies and those that contribute to the diagnosis, classification, or risk stratification of these neoplasms.

Recent advances in T-cell lymphoid neoplasms

T Cells comprise many subtypes of specified lymphocytes, and their differentiation and function take place in different tissues. This cellular diversity is also observed in the multiple ways T-cell transformation gives rise to a variety of T-cell neoplasms. This review covers the main types of T-cell malignancies and their specific characteristics, emphasizing recent advances at the cellular and molecular levels as well as differences and commonalities among them.

Emerging Therapeutic Landscape of Peripheral T-Cell Lymphomas Based on Advances in Biology: Current Status and Future Directions

Simple Summary

Peripheral T-cell lymphoma is a rare but aggressive tumor. Due to its rarity, the disease has not been completely understood. In our review, we look at this lymphoma at the molecular level based on available literature. We highlight the mechanism behind the progression and resistance of this tumor. In doing so, we bring forth possible mechanism that could be exploited through novel chemotherapy drugs. In addition, we also look at the current available drugs used in treating this disease, as well as highlight other new drugs, describing their potential in treating this lymphoma. We comprehensively have collected and present the available biology behind peripheral T-cell lymphoma and discuss the available treatment options.

Abstract

T-cell lymphomas are a relatively rare group of malignancies with a diverse range of pathologic features and clinical behaviors. Recent molecular studies have revealed a wide array of different mechanisms that drive the development of these malignancies and may be associated with resistance to therapies. Although widely accepted chemotherapeutic agents and combinations, including stem cell transplantation, obtain responses as initial therapy for these diseases, most patients will develop a relapse, and the median survival is only 5 years. Most patients with relapsed disease succumb within 2 to 3 years. Since 2006, the USFDA has approved five medications for treatment of these diseases, and only anti-CD30-therapy has made a change in these statistics. Clearly, newer agents are needed for treatment of these disorders, and investigators have proposed studies that evaluate agents that target these malignancies and the microenvironment depending upon the molecular mechanisms thought to underlie their pathogenesis. In this review, we discuss the currently known molecular mechanisms driving the development and persistence of these cancers and discuss novel targets for therapy of these diseases and agents that may improve outcomes for these patients.

Hepatosplenic T-cell lymphoma: treatment challenges

PURPOSE OF REVIEW

Hepatosplenic lymphoma (HSTCL) is a rare T-cell malignancy occurring in young males, associated with immune deficiency in 20% of the cases which, despite aggressive treatments, has a poor survival. Specific recommendations for first-line treatment remain debatable.

RECENT FINDINGS

Published data covering case reports or series of HSTCL concur that allogeneic stem cell transplant should be proposed as a consolidation after response to chemotherapy in all patients eligible for transplant. In the light of two recent clinical examples, we also confirm that specific chemotherapy and a first-line consolidation with allogeneic transplantation when a donor is available to represent a treatment of choice these rare and distinctive lymphomas. Recent molecular studies are summarized in this review and suggest potential targets for new therapeutic strategies.

SUMMARY

Major progresses have been achieved in improving the outcome of HSTCL l patients using intensive chemotherapy and allogeneic transplantation.

Chronic T cell receptor stimulation unmasks NK receptor signaling in peripheral T cell lymphomas via epigenetic reprogramming

Peripheral T cell lymphomas (PTCLs) represent a significant unmet medical need with dismal clinical outcomes. The T cell receptor (TCR) is emerging as a key driver of T lymphocyte transformation. However, the role of chronic TCR activation in lymphomagenesis and in lymphoma cell survival is still poorly understood. Using a mouse model, we report that chronic TCR stimulation drove T cell lymphomagenesis, whereas TCR signaling did not contribute to PTCL survival. The combination of kinome, transcriptome, and epigenome analyses of mouse PTCLs revealed a NK cell-like reprogramming of PTCL cells with expression of NK receptors (NKRs) and downstream signaling molecules such as Tyrobp and SYK. Activating NKRs were functional in PTCLs and dependent on SYK activity. In vivo blockade of NKR signaling prolonged mouse survival, demonstrating the addiction of PTCLs to NKRs and downstream SYK/mTOR activity for their survival. We studied a large collection of human primary samples and identified several PTCLs recapitulating the phenotype described in this model by their expression of SYK and the NKR, suggesting a similar mechanism of lymphomagenesis and establishing a rationale for clinical studies targeting such molecules.

Targeting EZH2 for the treatment of hepatosplenic T-cell lymphoma

We report a patient with hepatosplenic T-cell lymphoma (HSTL) and compare the disease to the derived xenograft model. Enhancer of zeste homolog 2 (EZH2) inhibitor treatment of an EZH2-mutant HSTL patient-derived xenograft model led to prolonged survival.

Molecularly targeted therapies for relapsed and refractory peripheral T-cell lymphomas

The advent of molecularly targeted agents for patients with peripheral T-cell lymphomas (PTCL) has begun to change the therapeutic landscape in these diseases, especially for patients with relapsed or refractory disease. These agents, grounded in targeting numerous pathways or alterations related to disease pathogenesis, have shown promise across many PTCL subhistologies. Aided by significant advances in experimental techniques related to molecular biology, epigenetics, and immunology, more recent studies have begun elucidating mediators of resistance, both intrinsic and acquired, to inform future therapeutic advances. Defining and targeting these escape mechanisms through rational combination approaches will likely be important to continue to build on these promising advances and further improve clinical outcomes for patients facing PTCL.

Hepatosplenic T-cell lymphoma: a rare but challenging entity

Hepatosplenic T-cell lymphoma (HSTCL) is a rare T-cell neoplasm that most commonly arises from a small subset of γ/δ T-cell receptor-expressing lymphocytes. HSTCL is more common in adolescent and young adults and has a rapidly progressive clinical course and poor outcome due to its refractoriness to conventional chemotherapy regimens. Approximately 20% of the cases arise in the background of chronic immunosuppression or immune dysregulation. Patients commonly present with constitutional symptoms, hepatic and liver enlargement, and cytopenias; hematophagocytic syndrome can also occur. The most frequent chromosomal aberrations associated with HSTCL are isochromosome 7q and trisomy 8, and most cases harbor mutations in genes involved in chromatin modification or the JAK/STAT pathway. The rarity of this disease, along with lack of nodal involvement and presenting symptoms that mimic different entities including infectious etiologies, makes this lymphoma a significant diagnostic challenge. In this review, we highlight the clinical and pathologic features of HSTCL. Moreover, we summarize the results of recent molecular studies suggesting potential targets for novel therapeutics strategies.

NCCN Guidelines Insights: T-Cell Lymphomas, Version 1.2021

Hepatosplenic T-cell lymphoma (HSTCL) is a rare subtype of T-cell lymphoma associated with an aggressive clinical course and a worse prognosis. HSTCL develops in the setting of chronic immune suppression or immune dysregulation in up to 20% of cases and is most often characterized by spleen, liver, and bone marrow involvement. Diagnosis and management of HSTCL pose significant challenges given the rarity of the disease along with the absence of lymphadenopathy and poor outcome with conventional chemotherapy regimens. These Guidelines Insights focus on the diagnosis and treatment of HSTCL as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Peripheral T cell lymphomas: from the bench to the clinic

Peripheral T cell lymphomas (PTCLs) are a heterogeneous group of orphan neoplasms. Despite the introduction of anthracycline-based chemotherapy protocols, with or without autologous haematopoietic transplantation and a plethora of new agents, the progression-free survival of patients with PTCLs needs to be improved. The rarity of these neoplasms, the limited knowledge of their driving defects and the lack of experimental models have impaired clinical successes. This scenario is now rapidly changing with the discovery of a spectrum of genomic defects that hijack essential signalling pathways and foster T cell transformation. This knowledge has led to new genomic-based stratifications, which are being used to establish objective diagnostic criteria, more effective risk assessment and target-based interventions. The integration of genomic and functional data has provided the basis for targeted therapies and immunological approaches that underlie individual tumour vulnerabilities. Fortunately, novel therapeutic strategies can now be rapidly tested in preclinical models and effectively translated to the clinic by means of well-designed clinical trials. We believe that by combining new targeted agents with immune regulators and chimeric antigen receptor-expressing natural killer and T cells, the overall survival of patients with PTCLs will dramatically increase.

A case of hepatosplenic T-cell lymphoma successfully treated by HLA haploidentical stem cell transplantation

We report a case of hepatosplenic T-cell lymphoma (HSTL) transplanted from an HLA-haploidentical daughter. A 51-year-old man was referred due to liver function test abnormalities and fever. He was confirmed to have γδ-type HSTL by bone marrow and liver biopsies. He was treated with five cycles of a CHOP regimen. Although metabolic complete response (CR), as defined by positron emission tomography, was achieved, his bone marrow still contained tumor cells on polymerase chain reaction (PCR). He underwent transplantation using unmanipulated peripheral blood stem cells from his HLA-haploidentical daughter. The preconditioning regimen consisted of fludarabine, melphalan, busulfan and antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and short-term methotrexate. Neutrophil engraftment was achieved on day 14. His bone marrow exhibited a completely female phenotype by fluorescence in situ hybridization, and no lymphoma cells were detected by PCR on day 30. Although he developed grade II acute GVHD on day 47, it was successfully treated by prednisolone. He has a limited type of skin chronic GVHD and still receives oral immunosuppressive therapy. He remains in CR four years after transplantation.

T-cell lymphoproliferative processes in the spleen

T-cell lymphoproliferative processes in the spleen are rare and it is important to study normal T cell subsets in the spleen to understand the splenic milieu in which they arise. True malignant T-cell processes including hepatosplenic T-cell lymphoma and T-cell large granular lymphocytic leukemia occur in the spleen, but other atypical reactive T-cell proliferations and those of uncertain significance also have been described. Proper distinction of florid T cell responses from malignant T-cell neoplasms has important therapeutic implications for the patient.

Case of a CD3 Negative Hepatosplenic T-Cell Lymphoma: Diagnostic and Therapeutic Challenges

Hepatosplenic T-cell lymphomas (TCLs) are a rare, aggressive subset of TCLs, accounting for less than 5% of all peripheral T-cell and natural killer (NK) cell lymphomas. We report the case of a CD3 negative hepatosplenic T-cell lymphoma in a 42-year-old female, who presented with left-sided abdominal pain. She underwent a liver biopsy that showed marked abnormal sinusoidal lymphoid infiltration. PET scan revealed increased splenic and pharyngeal lymph node uptake. Immunophenotype was remarkable for negative CD3, gamma delta T-cell receptor, and alpha beta-T-cell receptor expression. She received 6 cycles of DA-EPOCH, had primary refractory disease and then underwent palliative splenectomy secondary to painful necrosis. Then, she was started on pralatrexate as a single agent and then in combination with romidepsin as a potential bridge to an allogeneic stem cell transplantation from her sibling.

Deregulated expression of NKL homeobox genes in T-cell lymphomas

Recently, we have presented a scheme, termed "NKL-code", which describes physiological expression patterns of NKL homeobox genes in early hematopoiesis and in lymphopoiesis including main stages of T-, B- and NK-cell development. Aberrant activity of these genes underlies the generation of hematological malignancies notably T-cell leukemia. Here, we searched for deregulated NKL homeobox genes in main entities of T-cell lymphomas comprising angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), adult T-cell leukemia/lymphoma (ATLL), hepatosplenic T-cell lymphoma (HSTL), NK/T-cell lymphoma (NKTL) and peripheral T-cell lymphoma (PTCL). Our data revealed altogether 19 aberrantly overexpressed genes in these types, demonstrating deregulated NKL homeobox genes involvement in T-cell lymphomas as well. For detailed analysis we focused on NKL homeobox gene MSX1 which is normally expressed in NK-cells. MSX1 was overexpressed in subsets of HSTL patients and HSTL-derived sister cell lines DERL-2 and DERL-7 which served as models to characterize mechanisms of deregulation. We performed karyotyping, genomic and expression profiling, and whole genome sequencing to reveal mutated and deregulated gene candidates, including the fusion gene CD53-PDGFRB. Subsequent knockdown experiments allowed the reconstruction of an aberrant network involved in MSX1 deregulation, including chromatin factors AUTS2 and mutated histone HIST1H3B(K27M). The gene encoding AUTS2 is located at chromosome 7q11 and may represent a basic target of the HSTL hallmark aberration i(7q). Taken together, our findings highlight an oncogenic role for deregulated NKL homeobox genes in T-cell lymphoma and identify MSX1 as a novel player in HSTL, implicated in aberrant NK- and T-cell differentiation.

Treatment and prognosis of mature (non-anaplastic) T- and NK-cell lymphomas in childhood, adolescents, and young adults

Paediatric non-Hodgkin lymphomas (pNHL) are a diverse group of malignancies characterised by nodal and/or extranodal involvement. Less common pNHL forms include those derived from mature T- and natural killer (NK) cells. Much of our current understanding of paediatric mature (non-anaplastic) T/NK-cell lymphomas with respect to pathogenesis, diagnosis and treatment is extrapolated from adult literature. At the Sixth International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma, convened September 26-29, 2018 in Rotterdam, The Netherlands, some important aspects on diagnosis and outcomes of mature (non-anaplastic) T/NK-cell lymphoma in children and adolescents were discussed and will be reviewed in here.

A rare case of hepatosplenic gamma-delta T-cell lymphoma and secondary hemophagocytic lymphohistiocytosis

Hepatosplenic gamma-delta T-cell lymphoma with concurrent hemophogocytic lymphohistiocytosis is a rare but well-recognized clinical scenario, associated with a grim prognosis. Clinicians must be aware of this aggressive type of lymphoma so that a prompt diagnosis can be made with timely initiation of systemic therapy and referral for bone marrow transplant.

Molecular and Genomic Landscape of Peripheral T-Cell Lymphoma

Peripheral T-cell lymphoma (PTCL) is an uncommon group of lymphoma covering a diverse spectrum of entities. Little was known regarding the molecular and genomic landscapes of these diseases until recently but the knowledge is still quite spotty with many rarer types of PTCL remain largely unexplored. In this chapter, the recent findings from gene expression profiling (GEP) studies, including profiling data on microRNA, where available, will be presented with emphasis on the implication on molecular diagnosis, prognostication, and the identification of new entities (PTCL-GATA3 and PTCL-TBX21) in the PTCL-NOS group. Recent studies using next-generation sequencing have unraveled the mutational landscape in a number of PTCL entities leading to a marked improvement in the understanding of their pathogenesis and biology. While many mutations are shared among PTCL entities, the frequency varies and certain mutations are quite unique to a specific entity. For example, TET2 is often mutated but this is particularly frequent (70-80%) in angioimmunoblastic T-cell lymphoma (AITL) and IDH2 R172 mutations appear to be unique for AITL. In general, chromatin modifiers and molecular components in the CD28/T-cell receptor signaling pathways are frequently mutated. The major findings will be summarized in this chapter correlating with GEP data and clinical features where appropriate. The mutational landscape of cutaneous T-cell lymphoma, specifically on mycosis fungoides and Sezary syndrome, will also be discussed.

Hepatosplenic T-Cell Lymphomas

Hepatosplenic T-cell lymphoma (HSTL) is a rare variant of extranodal peripheral T-cell lymphomas (PTCL), associated with aggressive disease course and a relentless track record for lethal outcomes. HSTL presents commonly in young men in their third or fourth decade. Of the known causes, immune dysregulation and immunosuppression are the key players in the pathogenesis of HSTL. Clinical manifestation includes hepatosplenomegaly, fevers, and weakness. Bone marrow involvement or organomegaly can cause cytopenias. Anthracycline-based regimens provide modest responses with most individuals dying within a year of diagnosis. Hematopoietic stem cell transplant (HSCT) can be offered to fit and eligible patients to prolong remissions. Disease relapse post chemotherapy has an aggressive phenotype, with limited salvage options available in the setting of declining performance status. Understanding the disease biology further to identify mechanistic-driven drug discovery could overcome the current limitations of existing therapeutic armamentarium.

Tumor Microenvironment in T-Cell Lymphomas

T-cell lymphomas (TCL) are uncommon non-Hodgkin lymphomas that often have an aggressive clinical course. Patients typically have limited treatment options upon relapse and a dismal prognosis after progression despite newly approved therapies. New therapeutic approaches for these orphan diseases are very much needed and a greater understanding of the role of nonmalignant immune cells in the tumor microenvironment may allow for an improved antitumor immune response. The tumor microenvironment is a key component in tumor evasion and typically results in an ineffective T-cell response to the tumor cells despite a significant inflammatory response. A better understanding of the tumor microenvironment therefore, in an effort to overcome the barriers to an effective immune response, would help in developing novel therapeutic approaches to treat and improve outcomes of these diseases. Immune checkpoint blockade to reinvigorate suppressed T-cell, or modulation of the CD47-SIRPalpha axis to promote macrophage phagocytosis, would be such targets. However, whether modulating the immune response using each pathway alone or whether a combination approach is necessary has yet to be determined.

Use of PEG-asparaginase in a case of Hepatosplenic γδ T-cell lymphoma with long-term remission after stem cell transplantation

Hepatosplenic γδ T-cell lymphoma (HSTCL) is a rare aggressive peripheral T-cell lymphoma. Prognosis is usually poor with a median survival between 8 and 16 months after traditional chemotherapy. Stem cell transplantation (SCT) is promising and with a more intense induction regimen, has yielded positive results. We report the use of pegylated-asparaginase (PEG-asparaginase) along with a conventional anthracycline-containing regimen in a 51-year-old male who was diagnosed with HSTCL, achieved a complete remission, and subsequently underwent peripheral blood SCT and remained in remission at the time of this case report.

Successful second allogeneic stem-cell transplantation from the same sibling donor for a patient with recurrent hepatosplenic gamma-delta (γ/δ) T-cell lymphoma: A case report

RATIONALE

Hepatosplenic T-cell lymphoma (HSTCL) is a rare but aggressive type of peripheral T-cell lymphoma (PTCL). There is an urgent need for effective treatment due to the poor prognosis of HSTCL. Here, for the 1st time we describe the rare successful case of HSTCL who relapsed after a previous allogeneic stem-cell transplantation (allo-SCT), achieved remission with the second allo-SCT from the same donor.

PATIENT CONCERNS

A 24-year-old male, presented with a 2-week history of fever, drenching night sweats and nonquantified weight loss.

DIAGNOSES

Laboratory studies, flow cytometry of immunophenotyped, and physical examination results strongly suggested hepatosplenic γ/δ T-cell lymphoma, stage IVB.

INTERVENTIONS

We proceeded to an allo-SCT with a human leukocyte antigen (HLA) identical sibling donor. The bone marrow examination and fluorescent in situ hybridization were observed for complete donor chimerism of bone marrow cells on day 34. On day 157 after the initial allo-SCT, the bone marrow examination revealed the relapse of the sinusoidal infiltration with lymphoma cells. Considering the disease persistence, we conducted the second allo-SCT from the same HLA-identical sibling donor immediately.

OUTCOMES

Bone marrow examination indicated hematologic recovery without residual lymphoma cells.

LESSONS

Our encouraging outcome suggests that the latter allo-SCT needs to be considered early for patients with disease recurrence, and it also demonstrates that graft-vs-lymphoma conferred by allo-SCT may play an essential role on HSTCL treatment. Furthermore, detecting related genes at diagnosis may have prognostic implications and guidance value for personal chemotherapy program.

Hepatosplenic γδ T-cell lymphoma of two adolescents: Case report and retrospective literature review in children, adolescents, and young adults

HSTCL is a highly aggressive malignancy with a poor prognosis. Case series and accounts have reported the use of different chemotherapy regimens with diverse patient outcomes. Most long-term survivors had undergone high-dose chemotherapy with autologous or allogeneic HCT. We describe two pediatric patients with HSTCL who were treated with chemotherapy followed by allogeneic HCT. Both patients are alive and in complete remission 2 and 8 years after therapy. Multiagent chemotherapy followed with allogeneic HCT seems to provide patients who have chemotherapy-sensitive disease a long-term disease-free survival.

A rare case of hepatosplenic γδ T-cell lymphoma expressing CD19 with ring chromosome 7 and trisomy 8

Hepatosplenic T-cell lymphoma (HSTL) is a rare subtype of peripheral T-cell lymphoma predominantly seen in young males. This disease presents with isolated hepatosplenomegaly and thrombocytopenia with sinusoidal infiltration of liver and sinusal infiltration of spleen. Immunophenotype shows positivity for CD3, CD7, TCRγδ or TCRαβ, CD38 and double negative for CD4, CD8, TdT, CD5, and CD56. Isochromosome 7q with or without trisomy 8 is seen in HSTL. Recently, ring chromosome 7 has also been identified as a new abnormality. We describe the clinical, immunophenotypic and cytogenetic analysis in a 24-year-old woman. We present an unusual case of TCRγδ positive T-cell lymphoma with aberrant expression of CD19, which is a B-cell lymphoid marker, with amplification of 7q region and subsequent formation of ring chromosome 7 and trisomy 8. This is the second case of HSTL, positive for CD19 and first case presenting with ring chromosome 7 and trisomy 8 in a CD19 positive HSTL which is a rare finding in T-cell lymphoma and needs to be explored further.

Extranodal NK/T-cell lymphoma: Updates in biology and management strategies

Extranodal NK/T-cell lymphoma, nasal type (ENKL), is a rare lymphoma subtype of peripheral T/NK-cell lymphoma that is very common in East Asia and Latin America. Two-thirds of patients have localized disease in the nasal cavity or adjacent sites. Large retrospective studies have revealed the clinicopathologic features of ENKL patients, identified risk factors for short survival time, and developed prognostic models. Next-generation sequencing studies have provided a comprehensive list of recurrent mutations in ENKL. Since the early 2000s, disease-specific therapeutic approaches have been developed, and the standard of care for ENKL has markedly changed. Non-anthracycline-containing chemotherapy with or without radiotherapy is the current standard approach for ENKL treatment. Emerging therapies, including the use of immune checkpoint inhibitors, are being investigated.

Targetable vulnerabilities in T- and NK-cell lymphomas identified through preclinical models

T- and NK-cell lymphomas (TCL) are a heterogenous group of lymphoid malignancies with poor prognosis. In contrast to B-cell and myeloid malignancies, there are few preclinical models of TCLs, which has hampered the development of effective therapeutics. Here we establish and characterize preclinical models of TCL. We identify multiple vulnerabilities that are targetable with currently available agents (e.g., inhibitors of JAK2 or IKZF1) and demonstrate proof-of-principle for biomarker-driven therapies using patient-derived xenografts (PDXs). We show that MDM2 and MDMX are targetable vulnerabilities within TP53-wild-type TCLs. ALRN-6924, a stapled peptide that blocks interactions between p53 and both MDM2 and MDMX has potent in vitro activity and superior in vivo activity across 8 different PDX models compared to the standard-of-care agent romidepsin. ALRN-6924 induced a complete remission in a patient with TP53-wild-type angioimmunoblastic T-cell lymphoma, demonstrating the potential for rapid translation of discoveries from subtype-specific preclinical models.

T- and NK-cell lymphomas (TCL) are a group of lymphoid malignancies characterized by poor prognosis, but the absence of appropriate pre-clinical models has hampered the development of effective therapies. Here the authors establish several pre-clinical models and identify vulnerabilities that could be further exploited to treat patients afflicted by these diseases.

Hepatosplenic T-cell Lymphoma: a review of clinicopathologic features, pathogenesis, and prognostic factors

Hepatosplenic T-cell lymphoma (HSTCL) is a rare and clinically aggressive type of T-cell lymphoma that arises most often in adolescents and young adults. Patients with HSTCL commonly present with B-symptoms and cytopenias, which may suggest a diagnosis of acute leukemia initially. Patients present with extranodal disease involving the spleen, liver and bone marrow; lymphadenopathy is usually absent. The lymphoma cells can show a spectrum of cell sizes and are of T-cell lineage, often negative for CD4 and CD8 and positive for T-cell receptor γδ or, less often, αβ. Recent studies have identified gene mutations in oncogenic pathways that are likely involved in pathogenesis and may be targets for therapy. Mutations in STAT3 or STAT5B lead to activation of the JAK/STAT pathway, and mutations involving SETD2, IN080 and ARID1 are involved in chromatin modification. Currently, there is no consensus standard of care for HSTCL patients, although several studies support a role for allogeneic hematopoietic stem cell transplant. Although patients with HSTCL are best treated in the context of clinical trials, the rarity of these neoplasms likely necessitates a multi-institutional approach. In this review, we focus on the clinicopathologic and genetic characteristics of HSTCL. We also discuss the differential diagnosis and therapeutic approaches.

Gamma-delta (γδ) T-cell lymphoma - another case unclassifiable by World Health Organization classification: a case report

Background

We present a case of gamma-delta T-cell lymphoma that does not fit the current World Health Organization classifications.

Case presentation

A 74-year-old Caribbean-American woman presented with lymphocytosis, pruritus, and non-drenching night sweats. Bone marrow and peripheral blood analyses both confirmed the diagnosis of gamma-delta T-cell lymphoma. An axillary lymph node biopsy was negative for lymphoma. Clinically absent hepatosplenomegaly and skin lesions with biopsy-proven gamma-delta T-cell lymphoma suggest that she is unclassifiable within the current classification system.

Conclusions

We believe this is a case of not otherwise specified gamma-delta T-cell lymphoma. Accumulation of these rare not otherwise specified cases will be important for future classification which further defines the biology of this disease.

Expression of Vav3 protein and its prognostic value in patients with gastric cancer

Vav3 is associated with tumor growth, apoptosis, invasion, metastasis and angiogenesis. In this study, we detected the expression of Vav3 in gastric cancer tissues, and explored its role in invasion, metastasis and prognosis of gastric cancer. Vav3, MMP-2, MMP-9, TIMP-1 and TIMP-2 in primary lesion and pericarcinous tissues were tested with Immunohistochemistry and Western blot. Results showed a higher expression of Vav3 in primary lesion than in pericarcinous tissue, and the expression of Vav3 was significantly correlated with MMP-2, MMP-9 and TIMP-1 in gastric cancer tissues. Overexpression of Vav3 was associated with poorer differentiation, advanced clinical stage, more significant infiltration depth, lymphatic metastasis, and perineural invasion. Results of Kaplan-Meier verified that overexpression of Vav3 was related to poorer prognosis and shorter survival time. Moreover, Cox proportional hazard model revealed that overexpression of Vav3 was an independent risk factor of prognosis for patients with gastric cancer. In all, we conclude that overexpression of Vav3 is an independent risk factor for prognosis of gastric cancer, and can be used as a prognostic indicator. This may be because that Vav3 could regulate genes which associated with the invasion and metastasis.

The Genetic Basis of Hepatosplenic T-cell Lymphoma

Hepatosplenic T-cell lymphoma (HSTL) is a rare and lethal lymphoma; the genetic drivers of this disease are unknown. Through whole-exome sequencing of 68 HSTLs, we define recurrently mutated driver genes and copy-number alterations in the disease. Chromatin-modifying genes, including SETD2, INO80, and ARID1B, were commonly mutated in HSTL, affecting 62% of cases. HSTLs manifest frequent mutations in STAT5B (31%), STAT3 (9%), and PIK3CD (9%), for which there currently exist potential targeted therapies. In addition, we noted less frequent events in EZH2, KRAS, and TP53SETD2 was the most frequently silenced gene in HSTL. We experimentally demonstrated that SETD2 acts as a tumor suppressor gene. In addition, we found that mutations in STAT5B and PIK3CD activate critical signaling pathways important to cell survival in HSTL. Our work thus defines the genetic landscape of HSTL and implicates gene mutations linked to HSTL pathogenesis and potential treatment targets.Significance: We report the first systematic application of whole-exome sequencing to define the genetic basis of HSTL, a rare but lethal disease. Our work defines SETD2 as a tumor suppressor gene in HSTL and implicates genes including INO80 and PIK3CD in the disease. Cancer Discov; 7(4); 369-79. ©2017 AACR.See related commentary by Yoshida and Weinstock, p. 352This article is highlighted in the In This Issue feature, p. 339.

Alopecia Areata as a Manifestation of Systemic Lymphoma: Report of Two Cases

Alopecia areata is a common autoimmune disorder leading to hair loss. It usually affects individuals under the age of 40, and first appearance in older subjects is considered uncommon. Here, we report 2 cases of rapidly progressing alopecia areata, which appeared for the first time in adults. Patient 1 had alopecia universalis, which preceded the identification of hepatosplenic T-cell lymphoma, a rare form of lymphoma. Patient 2 suffered from the ophiasis type of alopecia areata, presenting for the first time following chemotherapy for non-Hodgkin B-cell lymphoma. These 2 cases highlight the need to screen for malignancies in patients who present with rapidly progressing alopecia areata for the first time after the age of 40.

CD1d-restricted peripheral T cell lymphoma in mice and humans

Peripheral T cell lymphomas (PTCLs) are a heterogeneous entity of neoplasms with poor prognosis, lack of effective therapies, and a largely unknown pathophysiology. Identifying the mechanism of lymphomagenesis and cell-of-origin from which PTCLs arise is crucial for the development of efficient treatment strategies. In addition to the well-described thymic lymphomas, we found that p53-deficient mice also developed mature PTCLs that did not originate from conventional T cells but from CD1d-restricted NKT cells. PTCLs showed phenotypic features of activated NKT cells, such as PD-1 up-regulation and loss of NK1.1 expression. Injections of heat-killed Streptococcus pneumonia, known to express glycolipid antigens activating NKT cells, increased the incidence of these PTCLs, whereas Escherichia coli injection did not. Gene expression profile analyses indicated a significant down-regulation of genes in the TCR signaling pathway in PTCL, a common feature of chronically activated T cells. Targeting TCR signaling pathway in lymphoma cells, either with cyclosporine A or anti-CD1d blocking antibody, prolonged mice survival. Importantly, we identified human CD1d-restricted lymphoma cells within Vδ1 TCR-expressing PTCL. These results define a new subtype of PTCL and pave the way for the development of blocking anti-CD1d antibody for therapeutic purposes in humans.