Activated oncogenic pathways and therapeutic targets in extranodal nasal-type NK/T cell lymphoma revealed by gene expression profiling

Oncogenic alterations in KIR3DL1 in cutaneous acral CD8+ lymphoproliferative disorder

BACKGROUND

Primary cutaneous acral CD8+ T-cell lymphoproliferative disorder (TLPD) is a rare and indolent lymphoma entity. Although TLPD was first identified many years ago, the molecular pathogenesis is still not fully understood.

OBJECTIVES

In order to better understand the molecular pathogenesis of cutaneous acral CD8+ TLPD and to identify further discriminatory markers to differentiate this lymphoma subtype from other CD8+ cutaneous lymphomas, we analysed five cases of cutaneous acral CD8+ TLPD for putative molecular alterations.

METHODS

Somatic alterations were assessed using whole-exome and targeted sequencing of paraffin-embedded tissue. Results were evaluated using immunohistochemical staining of respective relevant proteins. CD8+ cutaneous T-cell lymphomas (n = 12) served as control for KIR3DL1 staining.

RESULTS

Copy number variation analysis revealed a homozygous deletion of the KIR3DL1 gene in two of the analysed cases. This resulted in loss of KIR3DL1 protein expression, which was observed in all cases of cutaneous acral CD8+ TLPD. In contrast, KIR3DL1 expression was more variable in other CD8+ cutaneous T-cell lymphomas with 50% of analysed cases (n = 12) found to be positive. In addition, one further case of acral CD8+ TLPD harboured a loss-of-function mutation in the PIK3R1 gene, presumably activating the phosphoinositide 3-kinase-AKT pathway.

CONCLUSIONS

Alterations of the KIR3DL1 gene may be of pathogenetic relevance for acral CD8+ TLPD. Loss of KIR3DL1 protein expression may support the diagnosis of this indolent lymphoma entity; however, this is not a subtype-specific discriminative feature.

Resistance mechanisms and potential therapeutic strategies in relapsed or refractory natural killer/T cell lymphoma

ABSTRACT

Natural killer/T cell lymphoma (NKTCL) is a malignant tumor originating from NK or T cells, characterized by its highly aggressive and heterogeneous nature. NKTCL is predominantly associated with Epstein-Barr virus infection, disproportionately affecting Asian and Latin American populations. Owing to the application of asparaginase and immunotherapy, clinical outcomes have improved significantly. However, for patients in whom first-line treatment fails, the prognosis is exceedingly poor. Overexpression of multidrug resistance genes, abnormal signaling pathways, epigenetic modifications and active Epstein-Barr virus infection may be responsible for resistance. This review summarized the mechanisms of resistance for NKTCL and proposed potential therapeutic approaches.

Genomic analysis reveals molecular characterization of CD30+ and CD30- extranodal natural killer/T-cell lymphomas (ENKTLs)

Extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is prevalent in the Asian population; however, little is known about its molecular characteristics. In this study, we examined the CD30 expression in ENKTLs and then performed whole exome sequencing on ten CD30+ ENKTL and CD30- ENKTL paired samples. CD30 was positive in 55.74% of the ENKTLs. Single nucleotide and insertion/deletion polymorphism analyses revealed that 53.41% of the somatic mutations in CD30+ ENKTLs were shared with CD30- ENKTLs, including mutations in SERPINA9, MEGF6, MUC6, and KDM5A. Frequently mutated genes were primarily associated with cell proliferation and migration, the tumor microenvironment, energy and metabolism, epigenetic modulators, vascular remodeling, and neurological function. PI3K-AKT, cAMP, cGMP-PKG, and AMPK pathways were enriched in both CD30+ and CD30- ENKTLs. Copy number variation analysis identified a unique set of genes in CD30+ ENKTLs, including T-cell receptor genes (TRBV6-1 and TRBV8), cell cycle-related genes (MYC and CCND3), immune-related genes (GPS2, IFNA14, TTC38, and CTSV), and a large number of ubiquitination-related genes (USP32, TRIM23, TRIM2, DUSP7, and UBE2QL1). BCL10 mutation was identified in 6/10 CD30+ ENKTLs and 7/10 CD30- ENKTLs. Immunohistochemical analysis revealed that the expression pattern of BCL10 in normal lymphoid tissues was similar to that of BCL2; however, its expression in ENKTL cells was significantly higher (67.92% vs. 16.98%), implying the potential application of BCL10 inhibitors for treating ENKTLs. These results provide new insights into the genetic characteristics of CD30+ and CD30- ENKTLs, and could facilitate the clinical development of novel therapies for ENKTL.

From the midfacial destructive drama to the unfolding EBV story: a short history of EBV-positive NK-cell and T-cell lymphoproliferative diseases

Epstein-Barr virus (EBV) is a ubiquitous gammaherpesvirus that has been related to oncogenesis of lymphoid and epithelial malignancies. Although the mechanism of EBV infection of NK and T cells remains enigmatic, it plays a pathogenic role in various EBV+ NK-cell and T-cell lymphoproliferative diseases (LPDs), through promotion of cell activation pathways, inhibition of cell apoptotic pathways, behaving as oncogenes, interacting with host oncogenes or acting epigenetically. The study of NK-cell LPDs, previously hampered by the lack of immunophenotypical and genotypical criteria of NK cells, has become feasible with the recently accepted criteria. EBV+ NK- and T-cell LPDs are mostly of poor prognosis. This review delivers a short history from primeval to recent EBV+ NK- and T-cell LPDs in non-immunocompromised subjects, coupled with increasing interest, and work on the biological and oncogenic roles of EBV.

Analysis of mutation profiles in extranodal NK/T-cell lymphoma: clinical and prognostic correlations

The molecular pathogenesis of extranodal NK/T-cell lymphoma (NKTCL) remains obscured despite the next-generation sequencing (NGS) studies explored on ever larger cohorts in the last decade. We addressed the highly variable mutation frequencies reported among previous studies with comprehensive amplicon coverage and enhanced sequencing depth to achieve higher genomic resolution for novel genetic discovery and comparative mutational profiling of the oncogenesis of NKTCL. Targeted exome sequencing was conducted to interrogate 415 cancer-related genes in a cohort of 36 patients with NKTCL, and a total of 548 single nucleotide variants (SNVs) and 600 Copy number variances (CNVs) were identified. Recurrent amplification of the MCL1 (67%) and PIM1 (56%) genes was detected in a dominant majority of patients in our cohort. Functional mapping of genetic aberrations revealed that an enrichment of mutations in the JAK-STAT signaling pathway, including the cytokine receptor LIFR (copy number loss) upstream of JAK3, STAT3 (activating SNVs), and downstream effectors of MYC, PIM1 and MCL1 (copy number gains). RNA in situ hybridization showed the significant consistence of MCL1 RNA level and copy number of MCL1 gene. We further correlated molecular and clinical parameters with overall survival (OS) of these patients. When correlations were analyzed by univariate followed by multivariate modelling, only copy number loss of LIFR gene and stage (III-IV) were independent prognostic factors of reduced OS. Our findings identified that novel loss of LIFR gene significantly correlated with the adverse clinical outcome of NKTCL patients and provided therapeutic opportunities for this disease through manipulating LIFR.

Upregulation of Enhancer of Zeste Homolog 2 (EZH2) with Associated pERK Co-Expression and PRC2 Complex Protein SUZ12 Correlation in Adult T-Cell Leukemia/Lymphoma

EZH2, a subunit of the polycomb repressive complex 2 (PRC2), is an important methyltransferase that catalyzes the trimethylation of histone H3 at lysine 27 (H3K27me3). EZH2 is overexpressed in various malignancies. Here, we investigated EZH2 expression and potential signaling molecules that correlate with EZH2 expression in ATLL and other T-cell neoplasms. Immunohistochemical staining (IHC) was performed for EZH2, pERK, MYC, and pSTAT3 on 43 ATLL cases and 104 cases of other T-cell neoplasms. Further IHC studies were conducted for Ki-67, SUZ12, and H3K27me3 on ATLL cases. All ATLL cases showed EZH2 overexpression. In other T-cell neoplasms, a high prevalence of EZH2 overexpression was identified (86%), except for T-PLL (33%). In ATLL, EZH2 overexpression correlated with pERK co-expression (86%), while only a small subset of cases showed MYC (7%) or pSTAT3 (14%) co-expression. In the other T-cell neoplasms, there was a variable, but higher, co-expression of EZH2 with pERK, MYC, and pSTAT3. In ATLL, enhanced EZH2 expression correlated with higher Ki-67 staining, SUZ12 (another PRC2 subunit), and H3K27me3 co-expression. In conclusion, EZH2 is overexpressed in ATLL and is associated with pERK expression. It correlates with an increased proliferation index, indicating an aggressive clinical course. EZH2 also correlates with SUZ12 and H3K27me3 co-expression, suggesting its PRC2-dependent catalytic activity through trimethylation. Additionally, EZH2 is overexpressed in most T-cell neoplasms, suggesting that EZH2 could function as an oncogenic protein in T-cell tumorigenesis. EZH2 and pERK could serve as potential therapeutic targets for treating aggressive ATLL. EZH2 could also be targeted in other T-cell neoplasms.

Extranodal NK/T-Cell Lymphoma Predominantly Composed of Anaplastic Cells: A Frequently Misdiagnosed and Highly Aggressive Variant

Extranodal NK/T-cell lymphoma (ENKTL) is a non-Hodgkin lymphoma associated with the Epstein-Barr virus that primarily affects individuals in East Asia and indigenous populations in Central and South America. Morphologically, ENKTL typically consists of medium-sized cells or a combination of small and large cells. This report presents 10 cases characterized by predominantly anaplastic cells with diffuse expression of CD30, resembling anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK-negative ALCL) and demonstrating highly aggressive behavior. The cohort included 9 males and 1 female, ranging in age from 29 to 65 years (median age: 47 y). Eight patients presented with nasal disease, while 2 had non-nasal disease. Five patients had stage I/II disease, and the remaining 5 had stage III/IV disease. Morphologically, necrosis was observed in 9 cases, angiocentric-angiodestructive growth in 3 cases, and pseudoepitheliomatous hyperplasia in 2 cases. Anaplastic cells predominated in all cases, with some displaying eccentric, horseshoe-shaped, or kidney-shaped nuclei (referred to as "Hallmark" cells). The morphology profile was monomorphic in 3 cases and polymorphic in 7 cases. Immunohistochemically, all cases tested positive for cytotoxic granule markers (TIA1 and granzymeB) and Epstein-Barr virus-encoded RNA. Cytoplasmic expression of CD3ε and CD56 was observed in 9 of 10 cases. Interestingly, most cases (7 of 8) exhibited variable expression of MuM1, ranging from 10% to 90%. All cases showed diffuse positivity for CD30 but were negative for ALK, resulting in 3 cases being initially misdiagnosed as ALK-negative ALCL. Compared with nonanaplastic cases, anaplastic cells predominant ENKTL had a significantly higher frequency of "B" symptoms, bone marrow involvement, hemophagocytic lymphohistiocytosis, and higher Ki67 proliferative index. These findings provide valuable information for pathologists, expanding their understanding of the cytologic spectrum of ENKTL. This rare variant of ENKTL, characterized by the predominance of anaplastic cells and diffuse CD30 expression, exhibits high aggressiveness and should be differentiated from ALK-negative ALCL. Awareness of this uncommon variant is crucial in preventing misdiagnosis and ensuring the timely initiation of therapy.

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.

Advances and challenges of immunotherapies in NK/T cell lymphomas

Natural killer (NK)/T cell lymphoma (NKTCL) is a rare subtype of Epstein-Barr virus (EBV)-associated non-Hodgkin lymphoma characterized by poor clinical outcomes. It is more common in East Asian and Latin American countries. Despite the introduction of asparaginase/pegaspargase-based chemotherapy, the prognosis of patients with advanced NKTCL needs to be improved, and few salvage treatment options are available for relapsed/refractory patients who fail chemotherapy. Although many unknowns remain, novel treatment strategies to further improve outcomes are urgently needed. Immunotherapy has emerged and shown favorable antitumor activity in NKTCL, including monoclonal antibodies targeting immune checkpoint inhibitors, other receptors on the cellular membrane, and cellular immunotherapy, which could enhance immune cells attack on tumor cells. In this review, we provide an overview of recent immunotherapy in NKTCL, focusing on programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), chimeric antigen receptor (CAR) T cells, EBV-specific cytotoxic T lymphocytes, immunomodulatory agents, and other targeted agents, as well as the current progress and challenges in the field.

Extranodal lymphoma: pathogenesis, diagnosis and treatment

Approximately 30% of lymphomas occur outside the lymph nodes, spleen, or bone marrow, and the incidence of extranodal lymphoma has been rising in the past decade. While traditional chemotherapy and radiation therapy can improve survival outcomes for certain patients, the prognosis for extranodal lymphoma patients remains unsatisfactory. Extranodal lymphomas in different anatomical sites often have distinct cellular origins, pathogenic mechanisms, and clinical manifestations, significantly influencing their diagnosis and treatment. Therefore, it is necessary to provide a comprehensive summary of the pathogenesis, diagnosis, and treatment progress of extranodal lymphoma overall and specifically for different anatomical sites. This review summarizes the current progress in the common key signaling pathways in the development of extranodal lymphomas and intervention therapy. Furthermore, it provides insights into the pathogenesis, diagnosis, and treatment strategies of common extranodal lymphomas, including gastric mucosa-associated lymphoid tissue (MALT) lymphoma, mycosis fungoides (MF), natural killer/T-cell lymphoma (nasal type, NKTCL-NT), and primary central nervous system lymphoma (PCNSL). Additionally, as PCNSL is one of the extranodal lymphomas with the worst prognosis, this review specifically summarizes prognostic indicators and discusses the challenges and opportunities related to its clinical applications. The aim of this review is to assist clinical physicians and researchers in understanding the current status of extranodal lymphomas, enabling them to make informed clinical decisions that contribute to improving patient prognosis.

Proteome analysis of CD5-positive diffuse large B cell lymphoma FFPE tissue reveals downregulation of DDX3X, DNAJB1, and B cell receptor signaling pathway proteins including BTK and Immunoglobulins

BACKGROUND

The molecular pathology of diffuse large B cell lymphoma (DLBCL) has been extensively studied. Among DLBCL subtypes, the prognosis of CD5-positive DLBCL is worse than that of CD5-negative DLBCL, considering the central nervous system relapse and poor response to R-CHOP therapy. However, the molecular mechanisms underlying the tumorigenesis and progression of CD5-positive DLBCL remain unknown.

METHODS

To identify molecular markers that can be targeted for treating DLBCL, a proteomic study was performed using liquid chromatography-mass spectrometry with chemically pretreated formalin-fixed paraffin-embedded specimens from CD5-positive (n = 5) and CD5-negative DLBCL patients (n = 6).

RESULTS

Twenty-one proteins showed significant downregulation in CD5-positive DLBCL compared to CD5-negative DLBCL. Principal component analysis of protein expression profiling in CD5-positive and CD5-negative DLBCL revealed that DNAJB1, DDX3X, and BTK, which is one of the B cell phenotypic proteins, were the most significantly downregulated proteins and served as biomarkers that distinguished both groups. Additionally, a set of immunoglobulins, including IgG4, exhibited significant downregulation. Immunohistochemistry analysis for BTK demonstrated reduced staining in CD5-positive DLBCL compared to CD5-negative DLBCL.

CONCLUSIONS

In conclusion, DNAJB1 and DDX3X, BTK, and a set of immunoglobulins are promising biomarkers. Probably, the suppression of BCR signaling is the unique phenotype of CD5-positive DLBCL. This formalin-fixed paraffin-embedded (FFPE)-based profiling may help to develop novel therapeutic molecularly targeted drugs for treating DLBCL.

Extranodal NK-/T-cell lymphoma, nasal type: what advances have been made in the last decade?

Extranodal NK-/T-cell lymphoma (ENKTCL) is a rare and highly aggressive malignancy with significant racial and geographic variations worldwide. In addition to the formerly "nasal-type" initial description, these lymphomas are predominantly extranodal in origin and typically cause vascular damage and tissue destruction, and although not fully understood, Epstein-Barr virus (EBV) has an important role in its pathogenesis. Initial assessment must include a hematopathology review of representative and viable tumor areas without necrosis for adequate immunohistochemistry studies, including EBV-encoded small RNA (EBER) in situ hybridization (ISH). Positron emission tomography with 18-fluorodeoxyglucose (¹⁸F-FDG-PET/CT) for accurate staging is essential, and most patients will have localized disease (IE/IIE) at diagnosis. Apart from other T-cell malignancies, the best treatment even for localized cases is combined modality therapy (chemotherapy plus radiotherapy) with non-anthracycline-based regimens. For advanced-stage disease, l-asparaginase-containing regimens have shown improved survival, but relapsed and refractory cases have very poor outcomes. Nowadays, even with a better understanding of pathogenic pathways, up-front therapy is completely based on chemotherapy and radiotherapy, and treatment-related mortality is not low. Future strategies targeting signaling pathways and immunotherapy are evolving, but we need to better identify those patients with dismal outcomes in a pre-emptive way. Given the rarity of the disease, international collaborations are urgently needed, and clinical trials are the way to change the future.

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.

Super-enhancer-driven TOX2 mediates oncogenesis in Natural Killer/T Cell Lymphoma

BACKGROUND

Extranodal natural killer/T-cell lymphoma (NKTL) is an aggressive type of non-Hodgkin lymphoma with dismal outcome. A better understanding of disease biology and key oncogenic process is necessary for the development of targeted therapy. Super-enhancers (SEs) have been shown to drive pivotal oncogenes in various malignancies. However, the landscape of SEs and SE-associated oncogenes remain elusive in NKTL.

METHODS

We used Nano-ChIP-seq of the active enhancer marker histone H3 lysine 27 acetylation (H3K27ac) to profile unique SEs NKTL primary tumor samples. Integrative analysis of RNA-seq and survival data further pinned down high value, novel SE oncogenes. We utilized shRNA knockdown, CRISPR-dCas9, luciferase reporter assay, ChIP-PCR to investigate the regulation of transcription factor (TF) on SE oncogenes. Multi-color immunofluorescence (mIF) staining was performed on an independent cohort of clinical samples. Various function experiments were performed to evaluate the effects of TOX2 on the malignancy of NKTL in vitro and in vivo.

RESULTS

SE landscape was substantially different in NKTL samples in comparison with normal tonsils. Several SEs at key transcriptional factor (TF) genes, including TOX2, TBX21(T-bet), EOMES, RUNX2, and ID2, were identified. We confirmed that TOX2 was aberrantly overexpressed in NKTL relative to normal NK cells and high expression of TOX2 was associated with worse survival. Modulation of TOX2 expression by shRNA, CRISPR-dCas9 interference of SE function impacted on cell proliferation, survival and colony formation ability of NKTL cells. Mechanistically, we found that RUNX3 regulates TOX2 transcription by binding to the active elements of its SE. Silencing TOX2 also impaired tumor formation of NKTL cells in vivo. Metastasis-associated phosphatase PRL-3 has been identified and validated as a key downstream effector of TOX2-mediated oncogenesis.

CONCLUSIONS

Our integrative SE profiling strategy revealed the landscape of SEs, novel targets and insights into molecular pathogenesis of NKTL. The RUNX3-TOX2-SE-TOX2-PRL-3 regulatory pathway may represent a hallmark of NKTL biology. Targeting TOX2 could be a valuable therapeutic intervene for NKTL patients and warrants further study in clinic.

Rational Targets of Therapy in Extranodal NK/T-Cell Lymphoma

Extranodal NK/T-cell lymphoma (ENKTL) is an aggressive extranodal non-Hodgkin lymphoma (NHL) with poor outcomes, particularly in advanced-stage and relapsed/refractory disease. Emerging research on molecular drivers of ENKTL lymphomagenesis by next-generation and whole genome sequencing has revealed diverse genomic mutations in multiple signaling pathways, with the identification of multiple putative targets for novel therapeutic agents. In this review, we summarize the biological underpinnings of newly-understood therapeutic targets in ENKTL with a focus on translational implications, including epigenetic and histone regulatory aberrations, activation of cell proliferation signaling pathways, suppression of apoptosis and tumor suppressor genes, changes in the tumor microenvironment, and EBV-mediated oncogenesis. In addition, we highlight prognostic and predictive biomarkers which may enable a personalized medicine approach toward ENKTL therapy.

Mature T-cell and NK-cell lymphomas: updates on molecular genetic features

Mature T-cell and NK-cell lymphomas are a heterogeneous group of rare and typically aggressive neoplasms. Diagnosis and subclassification have historically relied primarily on the integration of clinical, histologic, and immunophenotypic features, which often overlap. The widespread application of a variety of genomic techniques in recent years has provided extensive insight into the pathobiology of these diseases, allowing for more precise diagnostic classification, improved prognostication, and development of novel therapies. In this review, we summarize the genomic features of the most common types of mature T-cell and NK-cell lymphomas with a particular focus on the contribution of genomics to biologic insight, classification, risk stratification, and select therapies in the context of the recently published International Consensus and updated World Health Organization classification systems.

Types of T-cell lymphoma-a cytogenetic perspective

T cell lymphoma, a type of non-Hodgkin lymphomas is a rare form of malignancy with poor outcomes. TCLS are a heterogeneous group of lymphoid malignancies that occur in nodal and extranodal sites. There are two main types of TCLs namely T-lymphoblastic lymphoma/leukemia and Peripheral T-cell lymphomas classified based on clinical manifestations and cytogenetic mutations. The use of advance technology like karyotyping, fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH) has allowed us to study TCLs in detail and to observe a different biochemical change that occurs in different TCLs allowing us to classify and treat them differently. This review focuses on the different mutations occurring in different TCLs and how they help us distinguish one type from another.

Extranodal natural killer/T-cell lymphoma: An overview on pathology and clinical management

Natural killer (NK)/T-cell lymphomas arise mainly from NK-cells and occasionally T-cells, and are universally infected with Epstein Barr virus (EBV). They are uncommon lymphomas more prevalent in Asian and Central/South American populations. NK/T-cell lymphomas are clinically aggressive and predominantly extranodal. The most commonly involved sites are the nasal cavity, followed by non-nasal sites including the skin, gastrointestinal tract and testis. The diagnosis of extranodal NK/T-cell lymphoma is established with histological and immunohistochemical examination, together with the demonstration of EBV in the tumour cells. Staging by positron emission tomography computed tomography is essential to inform the optimal management. Plasma EBV DNA quantification should be performed as it serves as a marker for prognostication and treatment response. Survival outcomes of patients with early-stage disease are good following treatment with nonanthracycline based chemotherapy, together with sequential/concurrent radiotherapy. For advanced-stage disease, asparaginase-containing regimens are mostly used and allogeneic haematopoietic stem cell transplantation should be considered for those at high risk of relapse. Salvage chemotherapy is largely ineffective for relapsed/refractory disease, which has a grave prognosis. Novel therapeutic approaches including immune check-point blockade, EBV-specific cytotoxic T-cells, and monoclonal antibodies are being investigated to improve outcomes for those with high risk and relapsed/refractory disease.

Genomic profiling identifies distinct genetic subtypes in extra-nodal natural killer/T-cell lymphoma

Extra-nodal NK/T-cell lymphoma, nasal type (ENKTCL) is a highly aggressive Epstein-Barr virus associated lymphoma, typically presenting in the nasal and paranasal areas. We assembled a large series of ENKTCL (n = 209) for comprehensive genomic analysis and correlative clinical study. The International Lymphoma Prognostic Index (IPI), site of disease, stage, lymphadenopathy, and hepatomegaly were associated with overall survival. Genetic analysis revealed frequent oncogenic activation of the JAK/STAT3 pathway and alterations in tumor suppressor genes (TSGs) and genes associated with epigenomic regulation. Integrated genomic analysis including recurrent mutations and genomic copy number alterations using consensus clustering identified seven distinct genetic clusters that were associated with different clinical outcomes, thus constituting previously unrecognized risk groups. The genetic profiles of ENTKCLs from Asian and Hispanic ethnic groups showed striking similarity, indicating shared pathogenetic mechanism and tumor evolution. Interestingly, we discovered a novel functional cooperation between activating STAT3 mutations and loss of the TSG, PRDM1, in promoting NK-cell growth and survival. This study provides a genetic roadmap for further analysis and facilitates investigation of actionable therapeutic opportunities in this aggressive lymphoma.

Icaritin inhibits PLK1 to activate DNA damage response in NK/T cell lymphoma and increases sensitivity to GELOX regime

Natural killer/T cell lymphoma (NKTCL) is a highly aggressive subtype of non-Hodgkin lymphoma. Gemcitabine, oxaliplatin, and L-asparaginase (GELOX) is one of the first-line chemotherapy regimens of NKTCL. Yet, the prognosis of NKTCL is poor. Icaritin is an herb-derived monomer from icariin with antitumor effects. We found that icaritin induced proliferation inhibition and apoptosis of NKTCL both in vitro and in vivo. Moreover, icaritin inhibited the dissemination of NKTCL in vivo. RNA sequencing revealed the Polo-like kinase 1 (PLK1) gene and DNA damage response (DDR) as the targets of icaritin. Mechanistically, icaritin inhibited PLK1 to promote checkpoint kinase 2 (Chk2) homodimerization and its T387 phosphorylation, which further activated p53, leading to the activation of the DDR pathway. Moreover, inhibiting PLK1 increased Forkhead box O3a nuclear localization, the latter of which activated ataxia telangiectasia mutated (ATM), an early sensor of DNA damage. Then ATM phosphorylated Chk2 T68 and initiated Chk2 activation. Remarkably, the combined treatment of icaritin and GELOX achieved better antitumor efficacy than single treatment in vivo. In summary, our results proved the efficacy of icaritin treating NKTCL, provided insights into its antitumor molecular mechanism, and revealed the application value of icaritin in facilitating clinical NKTCL treatment.

Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders

The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type 'a' IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type 'b' IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.

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 the Diagnosis and Treatment of Natural Killer Cell Malignancies

Simple Summary

Natural killer (NK)/T-cell lymphomas are aggressive extranodal Epstein–Barr virus (EBV)-positive malignancies. They can be divided into three subtypes: nasal (involving the nose and upper aerodigestive tract), non-nasal (involving skin, gastrointestinal tract, testis and other organs) and disseminated (involving multiple organs). Lymphoma cells are positive for CD3ε, CD56, cytotoxic molecules and EBV-encoded small RNA. There is a predilection for Asian and Central/South American populations. Genome-wide association studies have identified lymphoma susceptibility loci in Asians. Positron emission tomography computed tomography and plasma EBV DNA quantification are crucial at diagnosis and follow-up. Stage I/II patients receive non-athracycline asparaginse-containing regimens, together with sequential/concurrent radiotherapy. Anthracycline-containing regimens are ineffective. Stage III/IV patients receive asparaginase-containing regimens, followed by allogeneic haematopoietic stem cell transplantation (HSCT). Autologous HSCT does not improve outcome. In relapsed/refractory patients, novel approaches include PD1/PD-L1 targeting, EBV-specific cytotoxic T-cells, and monoclonal antibodies. Small molecules including histone deacetylase inhibitors may be beneficial.

Abstract

Natural killer (NK)/T-cell lymphomas are aggressive malignancies. Epstein–Barr virus (EBV) infection in lymphoma cells is invariable. NK/T-cell lymphomas are divided into nasal, non-nasal, and disseminated subtypes. Nasal NK/T-cell lymphomas involve the nasal cavity and the upper aerodigestive tract. Non-nasal NK/T-cell lymphomas involve the skin, gastrointestinal tract, testis and other extranodal sites. Disseminated NK/T-cell lymphoma involves multiple organs, rarely presenting with a leukaemic phase. Lymphoma cells are positive for CD3ε (not surface CD3), CD56, cytotoxic molecules and EBV-encoded small RNA. There is a predilection for Asian and Central/South American populations. Genome-wide association studies have identified lymphoma susceptibility loci in Asian patients. Positron emission tomography computed tomography and plasma EBV DNA quantification are crucial evaluations at diagnosis and follow-up. Stage I/II patients typically receive non-athracycline regimens containing asparaginse, together with sequential/concurrent radiotherapy. Anthracycline-containing regimens are ineffective. Stage III/IV patients are treated with asparaginase-containing regimens, followed by allogeneic haematopoietic stem cell transplantation (HSCT) in suitable cases. Autologous HSCT does not improve outcome. In relapsed/refractory patients, novel approaches are needed, involving PD1/PD-L1 targeting, EBV-specific cytotoxic T-cells, and monoclonal antibodies. Small molecules including histone deacetylase inhibitors may be beneficial in selected patients. Future strategies may include targeting of signalling pathways and driver mutations.

CircADARB1 serves as a new biomarker in natural killer T-cell lymphoma and a potential regulator of p-Stat3

Background

Natural killer/T-cell lymphoma (NKTCL) is a rare and aggressive subtype of Non-Hodgkin’s Lymphoma. CircRNA has shown great potential to become a biomarker in plasma. In this study, we aimed to determine circRNA for its diagnostic and prognostic value and biological function in NKTCL.

Method

The circRNA microarray of plasma from NKTCL patients and healthy donors were conducted. The relative expressions of target circRNA were verified by qRT-PCR. We conducted function experiments in vitro and in vivo. Bioinformatics predicted the target miRNA of the target circRNA and the binding site was detected by the dual luciferase report assay. Downstream target protein was predicted and detected by western blot in vitro and immunohistochemistry in vivo.

Result

By analyzing the plasma circRNA microarrays in NKTCL, 6137 circRNAs were up-regulated and 6190 circRNAs were down-regulated. The relative expressions of circADARB1 were significantly higher in NKTCL patients. The knockdown of circADARB1 inhibited proliferation of NKTCL cells in vitro and in vivo. CircADARB1 could bind to miR-214-3p in the downstream and regulate the expression of p-Stat3. In nude mice tumor tissue, p-Stat3 was under-expressed in the circADARB1 knockdown group.

Conclusion

CircADARB1 was highly expressed in NKTCL plasma and circADARB1 was a potential biomarker to assist diagnosis and predict the response in NKTCL. CircADARB1 bound up to miR-214-3p and regulated p-Stat3.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02296-x.

Review on natural killer /T-cell lymphoma

Extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is strongly associated with Epstein-Barr virus (EBV) and has a high prevalence in Asian and in Central and South America. About 85% of ENKTLs derive from NK cells and 15% from T-cells. Various factors have been implicated in the development of ENKTL. Molecular pathogenesis of NK/T-cell lymphomas include mutations of genes, involving in the Janus Kinase (JAK)/ signal transducer and activator of transcription (STAT) pathway, RNA helicase family, epigenetic regulation, and tumor suppression. The relationship between ENKTL and human leukocyte antigen (HLA) has been demonstrated. Radiotherapy (RT) plays a key role in the first-line treatment of early-stage. In stage III/IV diseases, non-anthracycline-regimens-containing L-asparaginase are recommended. Although clinical remission after L-asparaginase-based combination therapy has been achieved in the majority of patients with advanced-stage or relapsed/refractory(r/r) ENKL, the long-term overall survival is still poor. Recently, immunotherapy and new therapeutic targets have gained much attention. In this article, we discuss the pathogenesis, diagnosis, prognostic models and management options of ENKTL. This article is protected by copyright. All rights reserved.

Epstein-Barr Virus-Associated T- and NK-Cell Lymphoproliferative Diseases: A Review of Clinical and Pathological Features

Simple Summary

In most Epstein–Barr virus (EBV)-infected individuals, the virus establishes a lifelong latent infection with no specific clinical manifestation. However, EBV primary infection and secondary reactivation may cause various EBV-associated lymphoproliferative disorders (LPD), including hematologic malignancies. Among them, EBV-positive T/NK LPD are uncommon diseases defined by the proliferation of T- or NK-cells infected by EBV, more commonly encountered in Asians and Latin Americans. They encompass a spectrum of disorders ranging from indolent reactive lesions to malignant and aggressive diseases. Despite novel insights from high-throughput molecular studies, the pathogenesis of these disorders is not well understood, and EBV-positive T/NK LPD diagnoses remain challenging due to their rarity and considerable overlap. Indeed, this article discusses new insights into EBV-positive T/NK LPD and focuses on diagnosis challenges, describing the difficulties to clarify the borders between overlapping LPD subtypes.

Abstract

Epstein–Barr virus (EBV) is a ubiquitous virus detected in up to 95% of the general population. Most people are asymptomatic, while some may develop a wide range of EBV-associated lymphoproliferative disorders (LPD). Among them, EBV-positive T/NK LPD are uncommon diseases defined by the proliferation of T- or NK-cells infected by EBV. The 2017 World Health Organization (WHO) classification recognizes the following entities characterized by different outcomes: chronic active EBV infection of T- or NK-cell types (cutaneous and systemic forms), systemic EBV-positive T-cell lymphoma of childhood, EBV-positive aggressive NK-cell leukemia, extra nodal NK/T-cell lymphoma nasal type, and the new provisional entity known as primary EBV-positive nodal T/NK-cell lymphoma. In addition, EBV associated-hemophagocytic lymphohistiocytosis is part of EBV-positive T/NK LPD, but has not been included in the WHO classification due to its reactive nature. Despite novel insights from high-throughput molecular studies, EBV-positive NK/T-cell LPD diagnoses remain challenging, especially because of their rarity and overlap. Until now, an accurate EBV-positive NK/T LPD diagnosis has been based on its clinical presentation and course correlated with its histological features. This review aims to summarize clinical, pathological and molecular features of EBV-positive T/NK LPD subtypes and to provide an overview of new understandings regarding these rare disorders.

Liquid biopsy in extranodal NK/T-cell lymphoma: a prospective analysis of cell-free DNA genotyping and monitoring

Satisfactory tumor material is often hard to obtain for molecular analysis in extranodal natural killer (NK)/T-cell lymphoma (NKTCL) at present. However, the accuracy and utility of circulating cell-free DNA (cfDNA) genotyping have not been adequately assessed in NKTCL. We therefore performed targeted next-generation sequencing on tumor tissues and a series of longitudinal plasma samples prospectively collected from a cohort of high-risk NKTCL patients. Concordance of genotyping results of paired baseline tumor and cfDNA and the predictive value of dynamic cfDNA monitoring were evaluated. At baseline, 59 somatic variants in 31 genes were identified in tumor and/or plasma cfDNA among 19 out of 24 high-risk NKTCL patients (79.2%). Plasma cfDNA had a sensitivity of 72.4% for detection of somatic variants identified in tumor biopsies before treatment. Plasma cfDNA also allowed the identification of mutations that were undetectable in tumor biopsies. These results were also verified in a validation cohort of an additional 23 high-risk NKTCL patients. Furthermore, longitudinal analysis showed that patients with rapid clearance of NKTCL-related mutations from plasma had higher complete remission rates (80.0% vs 0%; P = .004) and more favorable survival (1-year progression-free survival [PFS] rate, 79.0% vs 20.0%; P = .002) compared with those with persisting or emerging mutations in plasma. In addition, low cfDNA concentration before treatment was associated with favorable survival outcome for patients with NKTCL (1-year PFS, 90.0% vs 36.4%; P = .012). In conclusion, cfDNA mirrors tumor biopsy for detection of genetic alterations in NKTCL and noninvasive dynamic plasma cfDNA monitoring might be a promising approach for tracking response and survival outcome for patients with NKTCL.

Diagnostic approach to T- and NK-cell lymphoproliferative disorders in the gastrointestinal tract

Most gastrointestinal NK and T cell lymphomas are aggressive in behavior, although in recent years a subset of indolent lymphoproliferative disorders have been described, which must be distinguished from their more malignant mimics. Intestinal T-cell lymphomas may arise from intra-epithelial lymphocytes and display epitheliotropism, such as enteropathy-associated T-cell lymphoma and monomorphic epitheliotropic intestinal T-cell lymphoma. They are both aggressive in behavior but differ in their clinic-pathological features. On the other hand, intra-epithelial lymphocytes are not prominent in intestinal T-cell lymphoma, NOS, which is a diagnosis of exclusion and probably represents a heterogeneous group of entities. Indolent lymphoproliferative disorders of NK- and T-cells of both CD8 and CD4 subsets share a chronic, recurring clinical course but display differences from each other. CD8+ T-cell lymphoproliferative disorder of GI tract has a low proliferative fraction and does not progress nor undergo large cell transformation. Whilst NK-cell enteropathy runs an indolent clinical course, it may display a high proliferation fraction. On the other hand, CD4+ indolent T-cell lymphoproliferative disorder displays variable proliferation rates and may progress or transform after a number of years. In Asia and South America, it is not uncommon to see involvement of the gastrointestinal tract by EBV-associated extranodal NK/T cell lymphoma, nasal type, which must be distinguished from NK cell enteropathy and EBV-associated mucocutaneous ulcers.

EBV and the Pathogenesis of NK/T Cell Lymphoma

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

Molecular insights into pathogenesis and targeted therapy of peripheral T cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are biologically and clinically heterogeneous diseases almost all of which are associated with poor outcomes. Recent advances in gene expression profiling that helps in diagnosis and prognostication of different subtypes and next-generation sequencing have given new insights into the pathogenesis and molecular pathway of PTCL. Here, we focus on a broader description of mutational insights into the common subtypes of PTCL including PTCL not other specified type, angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, and extra-nodal NK/T cell lymphoma, nasal type, and also present an overview of new targeted therapies currently in various stages of clinical trials.

The interplay between EBV and KSHV viral products and NF-κB pathway in oncogenesis

Among the DNA tumor viruses Epstein-Barr virus (EBV) and Kaposi sarcoma herpesvirus (KSHV), account for a considerable percentage of virus-associated cancers. Deregulation of transcription factors signaling pathways is one of the most significant oncogenic characteristics of EBV and KSHV. NF-κB is a transcription factor that play a remarkable role in oncogenesis because of its function as a master regulator of a spectrum of genes involved in physiological and pathophysiological process. Constitutive activation of NF-κB is a frequent and well-described event in many human malignancies. Compelling evidence represent EBV and KSHV are capable of targeting different components of NF-κB cascade. Here, we summarized recent findings to clarify the precise relationship between dysregulation of NF-κB and EBV and KSHV-related malignancies. This essay also emphasizes on contribution of various viral products in developing cancer through alteration of NF-κB signaling pathway.

Matrine inhibits the growth of natural killer/T-cell lymphoma cells by modulating CaMKIIγ-c-Myc signaling pathway

Background

C-Myc overexpression is associated with poor prognosis and aggressive progression of natural killer/T-cell lymphoma (NKTCL). Matrine, a main alkaloid of the traditional Chinese herb Sophora flavescens Ait, has been shown to inhibit cellular proliferation and induce apoptosis of various cancer cells. The present study investigated the effects and possible mechanisms of matrine inhibiting the growth of natural killer/T-cell lymphoma cells.

Methods

The effects of matrine on the proliferation, apoptosis and expression of apoptotic molecules, STAT3, LMP1, RUNX3, EZH2 and activation of CaMKIIγ/c-Myc pathway were examined in cultured NKTCL cell line NK92 cells.

Results

In cultured NK92 cells, matrine inhibited the proliferation in a dose and time dependent manner. The IC₅₀ value of matrine was 1.71 mM for 72 h post exposure in NK92 cells. Matrine induced apoptosis with decreased Bcl-2 expression and the proteasome-dependent degradation of c-Myc protein in NK92 cells. c-Myc protein half-life in NK92 was reduced from 80.7 min to 33.4 min after matrine treatment, which meant the stability of c-Myc was decreased after matrine exposure. Furthermore, we found that matrine downregulated c-Myc phosphorylation at Ser62 together with the inhibition of CaMKIIγ, a key regulator of c-Myc protein in NKTCL. The downregulation of c-Myc transcription by matrine was mediated through LMP1 inhibition. We also observed that anti-proliferative activity of matrine was irrelevant to STAT3, RUNX3 and EZH2.

Conclusions

The results of the present study indicated that matrine inhibits the growth of natural killer/T-cell lymphoma cells by modulating LMP1-c-Myc and CaMKIIγ-c-Myc signaling pathway.

BCL11A Is Oncogenic and Predicts Poor Outcomes in Natural Killer/T-Cell Lymphoma

The current treatment for natural killer/T-cell lymphoma (NKTL) among advanced/relapsed patients is unsatisfying, thereby highlighting the need for novel therapeutic targets. B‐cell chronic lymphocytic leukemia/lymphoma 11 A (BCL11A), as a transcription factor, is oncogenic in several neoplasms. However, its function in NKTL remains unclear. Quantitative real-time polymerase chain reaction and Western blot analysis were used to measure the BCL11A expression levels among NKTL patients and in NKTL cell lines. Natural killer (NK) cells from healthy subjects were used as negative control. Transient transfection with small interfering RNA was used to knockdown the expression in NKTL cell lines. Samples and clinical histories were collected from 343 NKTL patients (divided into test and validation groups) to evaluate the clinical value of BCL11A expression level. The BCL11A expression was upregu\lated among NKTL patients and in NKTL cell lines. Reduced cell proliferation and increased apoptosis were observed after silencing BCL11A in NKTL cell lines. BCL11A expression level was correlated with RUNX3, c-MYC, and P53 in NKTL. Notably, a high BCL11A expression was correlated with unfavorable clinical characteristics and predicted poor outcomes in NKTL. In conclusion, BCL11A was overexpressed in NKTL, while its upregulation promoted tumor development. Therefore, BCL11A expression level may be a promising prognostic biomarker for NKTL.

The landscape of new drugs in extranodal NK/T-cell lymphoma

To date, much progress has been made in early-stage extranodal NK/T-cell lymphoma (ENKTCL), and risk-adapted therapy with radiotherapy (RT) alone for the low-risk group and RT combined with asparaginase-based chemotherapy (CT) for the high-risk group yields favorable outcomes. However, optimal treatment strategies have not been defined yet for advanced-stage ENKTCL. Historically, ENKTCL responded poorly to conventional anthracycline-based chemotherapy probably because of inherent multidrug resistance (MDR). The fact that ENKTCL cells lack asparagine synthetase (ASNS) activity warranted the use of L-asparaginase or pegaspargase as frontline chemotherapies. Even though, due to high mortality of the disease, approximately 50% patients failing the frontline therapy arrived at dismal clinical outcomes with a median progression-free survival (PFS) less than 8 months. As distinctive molecular and biological subgroups are increasingly discovered within the disease entity of ENKTCL, novel targeted therapies and immunotherapy are of the urgent need for those heterogeneous subgroups. In this review, we sought to summarize the preclinical and clinical results of 6 categories of promising targeted therapy and immunotherapy for the treatment of ENKTCL, including monoclonal antibodies, immune checkpoint inhibitors, small-molecular inhibitors, epigenetic therapy, immunomodulatory drugs, and adoptive T-cell therapy, and these might change the landscape of treatment for ENKTCL in the near future.

Genomic and Transcriptomic Characterization of Natural Killer T Cell Lymphoma

Natural killer/T cell lymphoma (NKTCL) is an aggressive and heterogeneous entity of non-Hodgkin lymphoma, strongly associated with Epstein-Barr virus (EBV) infection. To identify molecular subtypes of NKTCL based on genomic structural alterations and EBV sequences, we performed multi-omics study on 128 biopsy samples of newly diagnosed NKTCL and defined three prominent subtypes, which differ significantly in cell of origin, EBV gene expression, transcriptional signatures, and responses to asparaginase-based regimens and targeted therapy. Our findings thus identify molecular networks of EBV-associated pathogenesis and suggest potential clinical strategies on NKTCL.

Oncogenic Network and Hub Genes for Natural Killer/T-Cell Lymphoma Utilizing WGCNA

Natural killer (NK)/T-cell lymphoma (NKTCL) is a subtype of non-Hodgkin lymphoma with aggressive progression and poor prognosis. The molecular mechanisms of NKTCL have not been well-studied. Herein, we revealed the lymphoma-associated dysregulated genes and signaling pathways or biological processes in NKTCL. We characterized that the extracellular matrix (ECM) receptor interaction pathway and T-cell receptor signaling pathway were the main dysregulated pathways in NKTCL by Gene Ontology (GO) analysis and pathway enrichment analysis. By using weighted gene co-expression network analysis (WGCNA), the gene co-expression network of NKTCL (SRP049695) was constructed, and hub genes (LMO3, GRB14) were identified. In addition, another Gene Expression Omnibus (GEO) dataset (GSE69406) was used to validate these hub genes. Furthermore, these hub genes were identified and validated by survival analysis (GSE90597). These results provided novel insights into the pathogenesis of NKTCL. Of particular interest, LMO3 and GRB14 might be potential oncoproteins and biomarkers for the diagnosis and treatment of NKTCL.

Extranodal NK/T-Cell Lymphomas: The Role of Natural Killer Cells and EBV in Lymphomagenesis

Keywords: NK cells, extranodal NK/T-cell lymphoma, EBV.

LDOC1 is differentially expressed in thyroid cancer and display tumor-suppressive function in papillary thyroid carcinoma

The leucine zipper downregulated in cancer 1 (LDOC1) has been proposed as a regulator of transcription and cell signaling. We have previously demonstrated that LDOC1 is differentially expressed in papillary thyroid carcinoma (PTC), this study was designed to characterize LDOC1 expression in thyroid follicle originated cancer tissues and to specifically evaluate its function in thyroid carcinogenesis. LDOC1 expression was performed in human normal thyroid and thyroid cancer. LDOC1 function was characterized, in two PTC cell lines (TPC1 and BCPAP), through the analysis of in vitro cell proliferation, apoptosis, migration, and invasion along with in vivo tumor xenograft growth. Transduced BCPAP cells were stimulated with tumor necrosis factor α, and the levels of nuclear P65, Bax, Bcl-2, c-Myc, and XIAP were assessed. A luciferase reporter assay was used to measure nuclear factor-κB (NF-κB) activity, and the functional connection between LDOC1 effect and NF-κB activity was determined using a specific NF-κB inhibitor. Our results revealed that LDOC1 was translocated from the nucleus to the cytoplasm in human thyroid cancer, and was significantly downregulated in PTC compared with normal thyroid. LDOC1 overexpression in TPC1 resulted in a significant suppression of the malignant phenotype, whereas LDOC1 ablation in BCPAP promoted this phenotype. Additional studies demonstrated that LDOC1 ablation facilitated nuclear P65 expression and NF-κB activity. NF-κB inhibition reversed the effects of LDOC1 ablation on proliferation, apoptosis, migration, and invasion. Our findings confirmed that LDOC1 is a novel therapeutic target in PTC and provides new insight into the role of LDOC1 in PTC progression, through NF-κΒ signaling suppression.

Epstein-Barr virus-associated T- and NK-cell lymphoproliferative diseases: an update and diagnostic approach

Epstein-Barr virus (EBV)-positive T-cell and natural killer (NK)-cell lymphoproliferative diseases (EBV-TNKLPD) are a group of uncommon disorders characterised by EBV infection of T- and NK-cells. As a group, EBV-TNKLPD are more commonly encountered in Asians and Native Americans from Central and South America compared to Western populations. They encompass a spectrum of entities that range from non-neoplastic lesions such as EBV-associated haemophagocytic lymphohistiocytosis (EBV-HLH) to more chronic conditions with variable outcomes such as chronic active EBV infections (CAEBV) of T- and NK-cell type (cutaneous and systemic forms) and malignant diseases such as systemic EBV-positive T-cell lymphoma of childhood, aggressive NK-cell leukaemia, extranodal NK/T-cell lymphoma, nasal-type, and primary EBV-positive nodal T/NK-cell lymphoma. Due to their rarity, broad clinicopathological spectrum and significant morphological and immunophenotypic overlap, the diagnosis and precise classification of EBV-TNKLPD often pose a challenge to clinicians and pathologists. Correct classification of this group of rare diseases relies heavily on the age of onset, disease presentation, duration of symptoms and cell of origin (T- vs NK-cell lineage). In this review, we provide an update on the clinicopathological and molecular features of the various EBV-TNKLPD entities occurring in non-immunocompromised patients and present a practical algorithmic approach for the general pathologist who is confronted with these disorders in routine clinical practice.

Recurrent GNAQ mutation encoding T96S in natural killer/T cell lymphoma

Natural killer/T cell lymphoma (NKTCL) is a rare and aggressive malignancy with a higher prevalence in Asia and South America. However, the molecular genetic mechanisms underlying NKTCL remain unclear. Here, we identify somatic mutations of GNAQ (encoding the T96S alteration of Gαq protein) in 8.7% (11/127) of NKTCL patients, through whole-exome/targeted deep sequencing. Using conditional knockout mice (Ncr1-Cre-Gnaqfl/fl), we demonstrate that Gαq deficiency leads to enhanced NK cell survival. We also find that Gαq suppresses tumor growth of NKTCL via inhibition of the AKT and MAPK signaling pathways. Moreover, the Gαq T96S mutant may act in a dominant negative manner to promote tumor growth in NKTCL. Clinically, patients with GNAQ T96S mutations have inferior survival. Taken together, we identify recurrent somatic GNAQ T96S mutations that may contribute to the pathogenesis of NKTCL. Our work thus has implications for refining our understanding of the genetic mechanisms of NKTCL and for the development of therapies.

Identification of microRNAs modulated by DNA hypomethylating drugs in extranodal NK/T-cell lymphoma

To identify epigenetically silenced miRNAs and to investigate their influences on predictive target oncogenes in extranodal natural killer/T-cell lymphoma (NKTCL). Decitabine treatment was performed to evaluate methylated miRNAs in NKTCL cells. The relationship between a given miRNA and its target mRNA was validated using 24 tumor tissues. miR-379, miR-134, miR-20b, miR-376a, miR-654-3p, miR-143, miR-181c, miR-1225-5p, miR-1246, and miR-1275 were epigenetically silenced in SNK6 cells. miR-134, miR-376a, miR-143 and miR-181c significantly affected cellular viability. PDGFRα was regulated by miR-34a and miR-181c. miR-143, miR-20b and miR34a regulated STAT3 expression. miR-20b and miR-143 expression showed inverse correlations with STAT3 mRNA expression in NKTCL tissues. K-RAS was regulated by miR-181c. Downregulation of cell viability by salirasib treatment was identified. miRNAs were downregulated by DNA methylation, and several microRNAs affected the viability of NKTCL cells. miR-34a and miR-181c may be involved in the oncogenic progression of NKTCL through the regulation of PDGFRα, STAT3, and K-RAS.

Survivin is a prognostic marker and therapeutic target for extranodal, nasal-type natural killer/T cell lymphoma

Background

The relationship between survivin and extranodal, nasal-type natural killer/T cell lymphoma (ENKTCL) was unclearly established yet. We here studied the potential prognostic roles of survivin and its implication as a target in ENKTCL therapy.

Methods

ENKTCL patients' peripheral blood were collected and tested by ELISA. ENKTCL cell lines were cultured with or without survivin inhibitor and tested by MTT and Flow cytometry. According to the gene expression profiles from the ArrayExpress Archive under E-TABM-702, survivin co-regulated cluster was established by Coupled Two-way Clustering Algorithm.

Results

Seventeen point six percent of total 17 ENKTCL patients were serum survivin-positive. These patients had poorer outcome than that of negative cases (P<0.01). Analysis of survivin co-regulation genes in ENKTCL revealed that survivin was significantly involved in pluripotency, drug resistance, cell cycle and proliferation, indicating that it should be one of key regulators in ENKTCL and might be a latent therapeutic target. Our results just showed that YM155, a survivin inhibitor, had strong anti-tumor effect on ENKTCL cell lines in a dose dependent manner. It increased sub-G1 phase population and reduced G1- and G2-M phase populations (P<0.05). In addition, combining YM155 with DDP induced a larger decrease in cell viability than either agent alone and had a higher inhibition rate than Bliss index, suggesting their synergistic inhibition.

Conclusions

We concluded that survivin was a potential prognostic marker and a critical regulatory molecule in the pathological process of ENKTCL. It would be a promising target in drugs discovery for ENKTCL therapy.

NK/T-cell lymphomas

NK/T-cell lymphomas are extranodal EBV-related malignancies, mostly of NK-cell and occasionally of T-cell lineage. They are divided into nasal, non-nasal, and disseminated subtypes. Nasal NK/T-cell lymphomas involve the nose, nasopharynx and the upper aerodigestive tract. Non-nasal NK/T-cell lymphomas involve the skin, gastrointestinal tract, testis and other sites. Disseminated NK/T-cell lymphoma involves multiple organs, and may present with a leukemic phase. Initial evaluation requires positron emission tomography computed tomography (PET/CT) and quantification of circulating EBV DNA. Radiotherapy alone is inadequate with frequent relapses. Anthracycline-containing regimens are ineffective. Regimens incorporating asparaginase are currently the standard. For stage I/II disease, combined chemotherapy and radiotherapy is recommended. For stage III/IV disease, asparaginase-containing regimens are needed. Autologous hematopoietic stem cell transplantation (HSCT) is of limited efficacy, whereas allogeneic HSCT may be useful in patients with stage III/IV and relapsed diseases. Immunotherapy with antibodies against CD30, programmed cell death protein 1 and CD38 is promising.

Activated hippo signal pathway inhibits cell proliferation and promotes apoptosis in NK/T cell lymphoma cells

Background

Natural Killer T–Cell Lymphoma (NKTCL) is a subtype of Non‐Hodgkin's Lymphoma, and its morbidity is ranked the first of T‐Cell Lymphoma. Hippo signaling pathway is involved in the pathogenesis of tumors. However, the role of Hippo signaling pathway in the oncogenesis of NKTCL still remains unclear.

Methods

The expressions of mammalian sterile 20‐like kinase 1 (MST1) and Yes‐associated protein (YAP) were investigated by RT‐PCR and Western blotting. Cell viability was detected by MTT assays. Cell cycle and cell apoptosis were determined by flow cytometry. Cell proliferative capacity was detected by colony formation assay. Nude mice xenograft models were established and the tumor sections were analyzed by immunohistochemistry (IHC) staining.

Results

The expression of MST1 was significantly down‐regulated in NKTCL tissues (n = 30) and cell lines, while the expression of YAP was significantly up‐regulated, and the phosphorylation of YAP was inhibited. Overexpression of MST1, knockdown of YAP, or verteporfin (VP) treatment could inhibit cell proliferation, and promote cell cycle arrest and apoptosis in NKTCL cells, while knockdown of MST1 and overexpression of YAP promoted cell proliferation. Additionally, Bcl‐2/Bax ratio and downstream effectors of Hippo signaling pathway (c‐myc, survivin, cyclinD1, CTGF, and TEAD) were significantly decreased when MST1 was overexpressed and YAP was knocked down or after VP treatment. Furthermore, our mice model demonstrated that activation of Hippo signal pathway suppressed the tumorigenesis of NKTCL.

Conclusion

The activation of Hippo signal pathway via overexpressing MST1 or down‐regulating YAP can inhibit the tumorigenesis of NKTCL.

Epstein-Barr Virus-Positive Natural Killer/T-Cell Lymphoma

Extranodal natural killer/T-cell lymphoma, nasal type (ENKL), is a rare malignancy of Non-Hodgkin lymphoma characterized by an aggressive clinical course and poor prognosis. It shows strong association with Epstein-Barr virus infection and occurs more commonly in Asia and Latin America. Various genetic alterations have been identified in ENKL by gene expression profiling and sequencing techniques. The frequent deletion of chromosome 6q21 was reported to lead to the silence of several tumor suppressor genes. Also, there have been novel genetic mutations that were recently uncovered and were found to frequently activate several oncogenic pathways, including the JAK/STAT, NF-κB, and MAPK pathways. Besides, we believe that deregulated single genes and epigenetic dysregulation might be relevant to the mechanism of this disease and thus, may have the potential to shed lights on the development of new therapeutic strategies. The consensus on the standard treatment for ENKL has not yet been currently established. For localized ENKL patients, radiotherapy with concurrent chemotherapy and sequential patterns of chemotherapy and radiotherapy are recommended as first-line therapy. As for advanced or relapsed/refractory ENKL patients, the application of non-anthracycline-containing regimens have significantly improved the clinical outcome, contributing to higher response rate, longer overall survival and progression-free survival. Hematopoietic stem cell transplantation is widely recommended for consolidation after a complete remission or partial remission has been achieved. The anti-programmed death 1 antibody, an immune checkpoint inhibitor, has demonstrated favorable results in treating relapsed or refractory ENKL. Of the current ENKL treatment, researchers are still striving to validate how radiotherapy and chemotherapy should be optimally combined and which of the non-anthracycline-containing regimens is superior. In this review, we summarize the main genetic alterations frequently found in ENKL and their role in providing new insights into the therapeutic targets of this disease, and highlight the recent findings regarding new biologic markers, novel therapeutic strategies applied to this intriguing neoplasm.

Cyclin-dependent kinase 1 and survivin as potential therapeutic targets against nasal natural killer/T-cell lymphoma

Nasal natural killer/T-cell lymphoma (NNKTL) is closely associated with Epstein-Barr virus (EBV) and is characterized by poor prognosis, resulting from rapid progression of lesions in the affected organs. Recent data have shown that NNKTL is associated with the aberrant expression of cyclin-dependent kinase 1 (CDK1) and its downstream target survivin, but little is known about the functional roles of CDK1 and survivin in NNKTL. In the current study, we show that knockdown of the EBV-encoded oncoprotein latent membrane protein 1 (LMP1) induces downregulation of CDK1 and survivin in NNKTL cells. Immunohistochemistry detected CDK1 and survivin expression in LMP1-positive cells of NNKTL biopsy specimens. Inhibition of CDK1 and survivin in NNKTL cells with several inhibitors led to a dose-dependent decrease in cell proliferation. In addition, the Sp1 inhibitor mithramycin, which can downregulate both CDK1 and survivin, significantly suppressed the growth of established NNKTL in a murine xenograft model. Our results suggest that LMP1 upregulation of CDK1 and survivin may be essential for NNKTL progression. Furthermore, targeting CDK1 and survivin with Sp1 inhibitors such as mithramycin may be an effective approach to treat NNKTL, which is considered to be a treatment-refractory lymphoma.