DUSP22 and TP63 rearrangements predict outcome of ALK-negative anaplastic large cell lymphoma: a Danish cohort study

Peripheral T-cell lymphoma: From biology to practice to the future

Recent advancements in comprehending peripheral T-cell lymphomas (PTCLs) validate and broaden our perspective, highlighting their diverse nature and the varying molecular mechanisms underlying the entities. Based on a comprehensive accumulated understanding, the PTCLs currently overcome the most challenging features of any disease: rarity, incredible heterogeneity, and a lack of any established standard of care. The treatments deployed in the front-line are extrapolated from regimens developed for other diseases. The recent approval of the three drugs brentuximab vedotin (BV), pralatrexate, and belinostat for patients with relapsed or refractory disease has provided clues about pathophysiology and future directions, though challenges satisfying post-marketing requirements (PMR) for those accelerated approvals have led to one of those drugs being withdrawn and put the other two in jeopardy. Edits of the front-line regimens, often called CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-plus approaches, look more like CHOP-minus strategies, as the toxicity of five-drug regimens often reduces the dose intensity of the added 'novel' drug, nullifying any hope of an advance. The turmoil in the field produced by the aforementioned, coupled with an ever-changing classification, has left the field uncertain about the path forward. Despite these challenges, empiric findings from studies of novel drug approaches, coupled with a logic emerging from studies of PTCL lymphomagenesis, have begun to illuminate, albeit faintly for some, a potential direction. The empiric finding that drugs targeting the discrete components of the PTCL epigenome, coupled with the description of multiple mutations in genes that govern epigenetic biology, offers, at the very least, an opportunity to finally be hypothesis-driven. The most recent recognition that the only combination of drugs shown to markedly improve progression-free survival (PFS) in patients with relapsed disease is one based on dual targeting of different and discrete components of that epigenetic biology has established a possibility that circumnavigating chemotherapy addition studies is both plausible, feasible, and likely the best prospect for a quantum advance in this disease. Herein, we analyze PTCL through a 2025 lens, highlighting and underscoring walls that have impeded progress. We will critically explore all the clues and the panoramic view of PTCL research.

Therapeutic potential of targeting protein tyrosine phosphatases in liver diseases

Protein tyrosine phosphorylation is a post-translational modification that regulates protein structure to modulate demic organisms' homeostasis and function. This physiological process is regulated by two enzyme families, protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). As an important regulator of protein function, PTPs are indispensable for maintaining cell intrinsic physiology in different systems, as well as liver physiological and pathological processes. Dysregulation of PTPs has been implicated in multiple liver-related diseases, including chronic liver diseases (CLDs), hepatocellular carcinoma (HCC), and liver injury, and several PTPs are being studied as drug therapeutic targets. Therefore, given the regulatory role of PTPs in diverse liver diseases, a collated review of their function and mechanism is necessary. Moreover, based on the current research status of targeted therapy, we emphasize the inclusion of several PTP members that are clinically significant in the development and progression of liver diseases. As an emerging breakthrough direction in the treatment of liver diseases, this review summarizes the research status of PTP-targeting compounds in liver diseases to illustrate their potential in clinical treatment. Overall, this review aims to support the development of novel PTP-based treatment pathways for liver diseases.

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

The 5th edition of the World Health Organization Classification of mature lymphoid and stromal tumors - an overview and update

The purpose of this review is to give an overview on the conceptual framework and major developments of the upcoming 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid tumours (WHO-HAEM5) and to highlight the most significant changes made in WHO-HAEM5 compared with the revised 4th edition (WHO-HAEM4R) of lymphoid and stromal neoplasms. The changes from the revised 4th edition include the reorganization of entities by means of a hierarchical system that is realized throughout the 5th edition of the WHO classification of tumors of all organ systems, a modification of nomenclature for some entities, the refinement of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities. For the first time, tumor-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms are included in the classification.

Anaplastic Large Cell Lymphoma of the Spine: Report of a Rare Case

This abstract discusses a rare case of anaplastic large cell lymphoma (ALCL) involving the cervical and dorsal spine in a 17-year-old female. ALCL is a distinct subtype of lymphoma characterized by abnormal proliferation of lymphocytes and is divided into ALK-positive and ALK-negative subtypes. Spinal involvement in ALCL is uncommon, particularly in the cervical and dorsal regions. The patient presented with persistent fever, weakness, and delayed onset of severe neck pain. Diagnosis involved imaging, bone marrow biopsy, and lymph node biopsy. Treatment strategies for ALCL typically involve a multimodal approach, including chemotherapy, radiotherapy, and targeted therapy. However, due to the rarity of spinal involvement, treatment decisions are based on extrapolation from other ALCL cases. Prognosis is influenced by disease stage and ALK status, but specific outcomes for spinal involvement remain poorly established. This case emphasizes the need for considering lymphoma in patients with unexplained symptoms and abnormal imaging findings. It highlights the importance of further research to improve the understanding and management of ALCL with spinal involvement.

Updates in the Classification of T-cell Lymphomas and Lymphoproliferative Disorders

PURPOSE OF REVIEW

Mature T/NK-cell neoplasms comprise a heterogeneous group of diseases with diverse clinical, histopathologic, immunophenotypic, and molecular features. A clinically relevant, comprehensive, and reproducible classification system for T/NK-cell neoplasms is essential for optimal management, risk stratification, and advancing understanding of these diseases. Two classification systems for lymphoid neoplasms were recently introduced: the 5th edition of World Health Organization classification (WHO-HAEM5) and the 2022 International Consensus Classification (ICC). In this review, we summarize the basic framework and updates in the classification of mature T/NK-cell neoplasms.

RECENT FINDINGS

WHO-HAEM5 and ICC share basic concepts in classification of T/NK-cell neoplasms, emphasizing integration of clinical presentation, pathology, immunophenotype, and genetics. Major updates in both classifications include unifying nodal T-follicular helper-cell lymphomas into a single entity and establishing EBV-positive nodal T/NK-cell lymphoma as a distinct entity. However, some differences exist in taxonomy, terminology, and disease definitions. The recent classifications of mature T/NK-cell neoplasms are largely similar and provide new insights into taxonomy based on integrated clinicopathologic features.

Molecular basis for the functional roles of the multimorphic T95R mutation of IRF4 causing human autosomal dominant combined immunodeficiency

Interferon regulatory factor 4 (IRF4) is a transcription factor that regulates the development and function of immune cells. Recently, a new multimorphic mutation T95R was identified in the IRF4 DNA-binding domain (DBD) in patients with autosomal dominant combined immune deficiency. Here, we characterized the interactions of the wild-type IRF4-DBD (IRF4-DBDWT) and T95R mutant (IRF4-DBDT95R) with a canonical DNA sequence and several noncanonical DNA sequences. We found that compared to IRF4-DBDWT, IRF4-DBDT95R exhibits higher binding affinities for both canonical and noncanonical DNAs, with the highest preference for the noncanonical GATA sequence. The crystal structures of IRF4-DBDWT in complex with the GATA sequence and IRF4-DBDT95R in complexes with both canonical and noncanonical DNAs were determined, showing that the T95R mutation enhances the interactions of IRF4-DBDT95R with the canonical and noncanonical DNAs to achieve higher affinity and specificity. Collectively, our data provide the molecular basis for the gain-of-function and new function of IRF4T95R.

Anaplastic large cell lymphomas with equivocal DUSP22 FISH results: recommendations for clinical reporting and diagnostic evaluation

Anaplastic large cell lymphoma (ALCL), one of the most common T-cell lymphomas, shows unifying pathological features but is clinically and genetically heterogeneous. One genetic subgroup, characterized by recurrent DUSP22 rearrangements (R), has distinct morphologic, immunophenotypic, and molecular features and can be identified in routine pathology practice using a breakapart (BAP) fluorescence in situ hybridization (FISH) probe. However, some cases show equivocal BAP-FISH findings (BAP-FISHEQ) and the features of these cases are poorly understood. Here, we sought to characterize DUSP22 BAP-FISHEQ ALCLs further. First, we applied an immunohistochemistry (IHC) algorithm using TIA1, pSTAT3Y705, and LEF1, which can predict DUSP22-R with high accuracy. Among 37 BAP-FISHEQ ALCLs, 18 (49%) were IHC-algorithm positive (IHCPOS), 8 (21%) were IHC-algorithm negative (IHCNEG), and 11 (30%) were IHCEQ. In 32 BAP-FISHEQ cases, we also applied a dual-color, dual-fusion (D-FISH) probe for t(6;7)(p25.3;q32.3), which accounts for 45% of DUSP22-R ALCLs. Among BAP-FISHEQ cases, D-FISH was positive in 10/18 IHCPOS cases (56%), 0/9 IHCEQ cases (0%), and 0/5 IHCNEG cases (0%). Median survival in BAP-FISHEQ ALCLs was 105 months, intermediate between BAP-FISHPOS ALCLs (median survival not reached) and BAP-FISHNEG ALCLs (19 months). Thus, DUSP22 BAP-FISHEQ ALCLs are clinicopathologically heterogeneous, likely due to an admixture of cases with an unbalanced DUSP22-R and cases with focal deletions without rearrangement. For clinical reporting, we recommend that DUSP22 BAP-FISHEQ ALCLs be reported as equivocal, and not be grouped with BAP-FISHPOS ALCLs. Clinical adoption of an IHC algorithm, possibly supplemented by t(6; 7) D-FISH, could facilitate genetic subtyping in about two-thirds of BAP-FISHEQ ALCLs.

A comparison of the International Consensus and 5th WHO classifications of T-cell lymphomas and histiocytic/dendritic cell tumours

Since the publication in 2017 of the revised 4th Edition of the World Health Organization (WHO) classification of haematolymphoid tumours, here referred to as WHO-HAEM4, significant clinicopathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining the diagnostic criteria of several diseases, upgrading entities previously defined as provisional and identifying new entities. This process has resulted in two recent classification proposals of lymphoid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, focusing on T-cell lymphomas and histiocytic/dendritic cell tumours. Moreover, we update the genetic data of the various pathological entities. The main goal is to provide a tool to facilitate the work of the pathologists, haematologists and researchers involved in the diagnosis and treatment of these haematological malignancies.

Primary cutaneous anaplastic large cell lymphoma with over-expressed Ki-67 transitioning into systemic anaplastic large cell lymphoma: A case report

BACKGROUND

Primary cutaneous anaplastic large cell lymphoma (PC-ALCL) differs from systemic anaplastic large cell lymphoma (sALCL) in cell biological behavior, clinical features, treatment, and outcome. PC-ALCL has been reported to rarely transition into sALCL, but the underlying mechanism is not clear. Here we report such a case with certain characteristics that shed light on this.

CASE SUMMARY

Herein, we report a 43-year-old male with symptoms of a skin nodule and histologically confirmed PC-ALCL with high expression of Ki-67. After three months of observation, two skin nodules re-appeared with muscle layer involvement and was histologically confirmed as sALCL. Seventeen months after receiving six cycles of CHOP regimen, the patient had pain in the chest and back, cough, shortness of breath, and night sweats. This was confirmed as relapse of sALCL by immunohistochemistry and several organs, such as the lung were involved as shown by positron emission tomography/computed tomography. After four cycles of DICE plus chidamide regimens followed by auto-hematopoietic stem cell transplantation (ASCT), complete remission (CR) duration was achieved for twelve months while the patient was on maintenance with chidamide (20 mg) pills.

CONCLUSION

This case had significantly high expression of Ki-67 when diagnosed as PC-ALCL initially and then transitioned into sALCL, which is rare. Auto-ASCT combined with demethylation drugs effectively maintained CR and prolonged progression free survival.

Cytogenetics in the management of mature T-cell and NK-cell neoplasms: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Mature T-cell and natural killer (NK)-cell neoplasms (MTNKNs) are a highly heterogeneous group of lymphomas that represent 10-15 % of lymphoid neoplasms and have usually an aggressive behavior. Diagnosis can be challenging due to their overlapping clinical, histological and immunophenotypic features. Genetic data are not a routine component of the diagnostic algorithm for most MTNKNs. Indeed, unlike B-cell lymphomas, the genomic landscape of MTNKNs is not fully understood. Only few characteristic rearrangements can be easily identified with conventional cytogenetic methods and are an integral part of the diagnostic criteria, for instance the t(14;14)/inv(14) or t(X;14) abnormality harbored by 95 % of patients with T-cell prolymphocytic leukemia, or the ALK gene translocation observed in some forms of anaplastic large cell lymphoma. However, advances in molecular and cytogenetic techniques have brought new insights into MTNKN pathogenesis. Several recurrent genetic alterations have been identified, such as chromosomal losses involving tumor suppressor genes (SETD2, CDKN2A, TP53) and gains involving oncogenes (MYC), activating mutations in signaling pathways (JAK-STAT, RAS), and epigenetic dysregulation, that have improved our understanding of these pathologies. This work provides an overview of the cytogenetics knowledge in MTNKNs in the context of the new World Health Organization classification and the International Consensus Classification of hematolymphoid tumors. It describes key genetic alterations and their clinical implications. It also proposes recommendations on cytogenetic methods for MTNKN diagnosis.

TP63 fusions drive multicomplex enhancer rewiring, lymphomagenesis, and EZH2 dependence

Gene fusions involving tumor protein p63 gene (TP63) occur in multiple T and B cell lymphomas and portend a dismal prognosis for patients. The function and mechanisms of TP63 fusions remain unclear, and there is no target therapy for patients with lymphoma harboring TP63 fusions. Here, we show that TP63 fusions act as bona fide oncogenes and are essential for fusion-positive lymphomas. Transgenic mice expressing TBL1XR1::TP63, the most common TP63 fusion, develop diverse lymphomas that recapitulate multiple human T and B cell lymphomas. Here, we identify that TP63 fusions coordinate the recruitment of two epigenetic modifying complexes, the nuclear receptor corepressor (NCoR)-histone deacetylase 3 (HDAC3) by the N-terminal TP63 fusion partner and the lysine methyltransferase 2D (KMT2D) by the C-terminal TP63 component, which are both required for fusion-dependent survival. TBL1XR1::TP63 localization at enhancers drives a unique cell state that involves up-regulation of MYC and the polycomb repressor complex 2 (PRC2) components EED and EZH2. Inhibiting EZH2 with the therapeutic agent valemetostat is highly effective at treating transgenic lymphoma murine models, xenografts, and patient-derived xenografts harboring TP63 fusions. One patient with TP63-rearranged lymphoma showed a rapid response to valemetostat treatment. In summary, TP63 fusions link partner components that, together, coordinate multiple epigenetic complexes, resulting in therapeutic vulnerability to EZH2 inhibition.

A Comparison of the Fifth World Health Organization and the International Consensus Classifications of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare subset of non-Hodgkin lymphomas that often carry significant difficulty in diagnosis and classification because of their rarity and biological complexity. Previous editions of the World Health Organization (WHO) classifications of hemopoietic neoplasms in 2001, 2008, and 2017 aimed to standardize hemopoietic neoplasm diagnosis in general. Since then, crucial clinico-pathological, immunophenotypic, and recent molecular discoveries have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, upgrading entities previously defined as provisional, and identifying new entities. In 2022, two different models were proposed to classify hematolymphoid neoplasms: the 5th edition of the WHO classification (WHO-HAEM5) and the International Consensus Classification (ICC). Of note, a common nosography is mandatory to ensure progress in health science and ensure the basis for a real precision medicine. In this article, the authors summarized the main differences with the previous fourth WHO edition and reviewed the main discrepancies between the two newest classifications, as far as PTCLs are concerned.

The SALENTO prognostic model for limited-stage peripheral T-cell lymphoma from the International T-Cell Project Network

The natural history of limited-stage peripheral T-cell lymphomas (PTCLs) remains poorly defined. We investigated outcomes and prognostic variables in patients registered in the T-Cell Project (TCP) (#NCT01142674) to develop a model to predict overall survival (OS) for the common nodal PTCL subtypes (PTCL-NOS, AITL, ALCL). The model was validated in an independent data set from Australian and Brazilian registries. 211 patients registered in the TCP between 2006-2018 were studied. The median age was 59 years (range 18-88) and median follow-up was 49 months. One hundred twenty-seven patients (78%) received anthracycline-based regimens, 5 patients (3%) radiotherapy alone (RT), 24 patients (15%) chemotherapy+RT. 5-year OS and PFS were 47% and 37%, respectively. Age >60 years, elevated LDH and low serum albumin were independent prognostic factors. The model identified 3 groups with low- (26%, score 0), intermediate- (41%, score 1), and high-risk (33%, score 2-3) with 5-year OS of 78% (95% confidence interval [95% CI], 29-127), 46% (95% CI, 24-68), and 25% (95% CI, 20-30), respectively (P < 0.001) and 5-year PFS of 66% (95% CI, 33-99), 37% (95% CI, 9-65), and 17% (95% CI, 9-25), respectively (P < 0.001). The model demonstrated greater discriminatory power than established prognostic indices and an analogous distribution and outcomes in the 3 groups in the validation cohort of 103 patients. The SALENTO Model (Limited Stage Peripheral T-Cell Lymphoma Prognostic Model) is an objective, simple and robust prognostic tool. The high-risk group has poor outcomes, comparable to advanced stage disease, and should be considered for innovative first-line approaches.

TP53 mutations identify high-risk events for peripheral T-cell lymphoma treated with CHOP-based chemotherapy

Nodal peripheral T-cell lymphomas (PTCL), the most common PTCLs, are generally treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based curative-intent chemotherapy. Recent molecular data have assisted in prognosticating these PTCLs, but most reports lack detailed baseline clinical characteristics and treatment courses. We retrospectively evaluated cases of PTCL treated with CHOP-based chemotherapy that had tumors sequenced by the Memorial Sloan Kettering Integrated Mutational Profiling of Actionable Cancer Targets next-generation sequencing panel to identify variables correlating with inferior survival. We identified 132 patients who met these criteria. Clinical factors correlating with an increased risk of progression (by multivariate analysis) included advanced-stage disease and bone marrow involvement. The only somatic genetic aberrancies correlating with inferior progression-free survival (PFS) were TP53 mutations and TP53/17p deletions. PFS remained inferior when stratifying by TP53 mutation status, with a median PFS of 4.5 months for PTCL with a TP53 mutation (n = 21) vs 10.5 months for PTCL without a TP53 mutation (n = 111). No TP53 aberrancy correlated with inferior overall survival (OS). Although rare (n = 9), CDKN2A-deleted PTCL correlated with inferior OS, with a median of 17.6 months vs 56.7 months for patients without CDKN2A deletions. This retrospective study suggests that patients with PTCL with TP53 mutations experience inferior PFS when treated with curative-intent chemotherapy, warranting prospective confirmation.

Nodal peripheral T-cell lymphoma: Chemotherapy-free management, are we there yet?

Peripheral T-cell lymphomas (PTCLs) are a diverse and uncommon type of lymphoid malignancies with a dismal prognosis. Recent advances in genomic studies have shown recurring mutations that are changing our knowledge of the disease's molecular genetics and pathogenesis. As such, new targeted therapies and treatments to improve disease outcomes are currently being explored. In this review, we discussed the current understanding of the nodal PTCL biology with potential therapeutic implications and gave our insights on the promising novel therapies that are currently under study such as immunotherapy, chimeric antigen receptor T-cell therapy, and oncolytic virotherapy.

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.

ALK-negative anaplastic large cell lymphoma with DUSP22 rearrangement has distinctive disease characteristics with better progression-free survival: a LYSA study

ALK-negative anaplastic large cell lymphoma (ALCL) comprises subgroups harboring rearrangements of DUSP22 (DUSP22- R) or TP63 (TP63-R). Two studies reported 90% and 40% 5-year overall survival (OS) rates in 21 and 12 DUSP22-R/TP63- not rearranged (NR) patients, respectively, making the prognostic impact of DUSP22-R unclear. Here, 104 newly diagnosed ALK-negative ALCL patients (including 37 from first-line clinical trials) from the LYSA TENOMIC database were analyzed by break-apart fluorescence in situ hybridization assays for DUSP22-R and TP63-R. There were 47/104 (45%) DUSP22-R and 2/93 (2%) TP63-R cases, including one DUSP22-R/TP63-R case. DUSP22-R tumors more frequently showed CD3 expression (62% vs. 35%, P=0.01), and less commonly a cytotoxic phenotype (27% vs. 82%; P<0.001). At diagnosis, DUSP22- R ALCL patients more frequently had bone involvement (32% vs. 13%, P=0.03). The patient with DUSP22-R/TP63-R ALCL had a rapidly fatal outcome. After a median follow-up of 4.9 years, 5-year progression-free survival (PFS) and OS rates of 84 patients without TP63-R treated with curative-intent anthracycline-based chemotherapy were 41% and 53%, respectively. According to DUSP22 status, 5-year PFS was 57% for 39 DUSP22-R versus 26% for 45 triple-negative (DUSP22-NR/TP63-NR/ALK-negative) patients (P=0.001). The corresponding 5-year OS rates were 65% and 41%, respectively (P=0.07). In multivariate analysis, performance status and DUSP22 status significantly affected PFS, and distinguished four risk groups, with 4-year PFS and OS ranging from 17% to 73% and 21% to 77%, respectively. Performance status but not DUSP22 status influenced OS. The use of brentuximab vedotin in relapsed/refractory patients improved OS independently of DUSP22 status. Our findings support the biological and clinical distinctiveness of DUSP22- R ALK-negative ALCL. Its relevance to outcome in patients receiving frontline brentuximab vedotin remains to be determined.

DUSP22 rearrangement is associated with a distinctive immunophenotype but not outcome in patients with systemic ALK-negative anaplastic large cell lymphoma

DUSP22 rearrangement (R) has been associated with a favorable outcome in systemic ALK-negative anaplastic large cell lymphoma (ALCL). However, a recent study found that patients with DUSP22-R ALK-negative ALCL have a poorer prognosis than was reported initially. In this study, we compared the clinicopathological features and outcomes of patients with ALKnegative ALCL with DUSP22-R (n=22) versus those without DUSP22-R (DUSP22-NR; n=59). Patients with DUSP22-R ALCL were younger than those with DUSP22-NR neoplasms (P=0.049). DUSP22-R ALK-negative ALCL cases were more often positive for CD15, CD8, and less frequently expressed pSTAT3Tyr705, PD-L1, granzyme B and EMA (all P<0.05). TP63 rearrangement (TP63-R) was detected in three of the 66 (5%) ALK-negative ALCL cases tested and none of these cases carried the DUSP22-R. Overall survival of patients with DUSP22-R ALCL was similar to that of the patients with DUSP22-NR neoplasms regardless of International Prognostic Index score, stage, age, or stem cell transplantation status (all P>0.05), but was significantly shorter than that of the patients with ALK-positive ALCL (median overall survival 53 months vs. undefined, P=0.005). Five-year overall survival rates were 40% for patients with DUSP22-R ALCL versus 82% for patients with ALK-positive ALCL. We conclude that DUSP22-R neoplasms represent a distinctive subset of ALK-negative ALCL. However, in this cohort DUSP22-R was not associated with a better clinical outcome. Therefore, we suggest that current treatment guidelines for this subset of ALK-negative ALCL patients should not be modified at present.

Anaplastic Large Cell Lymphomas With The 6p25.3 Rearrangement Are A Heterogeneous Group Of Tumours With A Diverse Molecular Background

ALK-negative anaplastic large cell lymphoma (ALCL) cases with 6p25.3 rearrangement are characterized by peculiar morphological and immunohistochemical features compare to 6p25.3-negative ALK-negative ALCL cases. A subgroup of 6p25.3-positive ALK-negative ALCL cases show the t(6,7)(p25.3;q32.3) rearrangement. Aims: To analyse the differences between 6p25.3-rearranged cases with and without t(6,7)(p25.3;q32.3). Using RNA-sequencing we studied a series of 17 samples showing 6p25.3-rearrangement, identified by FISH, consisting of seven systemic and eight primary cutaneous cases including two examples of secondary skin involvement by systemic ALCL. RNA-sequencing exclusively detected a translocation involving a gene in the 6p25.3 region (either IRF4 or DUSP22) in 7/14 cases (50%). In six of these seven cases the partner proved to be the LINC-PINT region in chromosome 7, while an EXOC2::DUSP22 rearrangement was found in one case. All cases but one were primary cutaneous ALCLs. They all were CD3 positive and BCL2 negative, while most of them expressed p-STAT3. On the contrary, cases without the t(6,7)(p25.3;q32.3) were mainly systemic (71%, 5/7) against just two pcALCL. In general, they lose CD3 (50% positive) and p-STAT3 (25% positive) expression, being all of them BCL2 positive. Moreover, in 60% of them other gene fusions were found. At the transcriptional level, they were characterized by the overexpression of TCF3 (TCF7L1/E2A), DLL3, CD58 and BCL2 genes. 75%(6/8) of pcALCL with 6p25.3 rearrangement featured the so-called "biphasic morphologic pattern, which was not found in cutaneous involvement from systemic ALCL. 83% (5/6) of the pcALCL cases with the "biphasic morphologic pattern" showed the t(6,7)(p25.3;q32.3) rearrangement. ALK-negative ALCL cases with 6p25.3 rearrangement are a subgroup of tumours that are heterogeneous with respect to the presence or absence of the t(6,7)(p25.3;q32.3) translocation.

A novel nomogram for predicting overall survival in peripheral T cell lymphoma patients.. [DOI: 10.21203/rs.3.rs-2823604/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background The prognosis of peripheral T cell lymphomas (PTCLs) varies greatly. This study aimed at generating a prognostic nomogram based on differentially expressed genes (DEGs).Methods Firstly, we collected RNA transcripts from Gene Expression Omnibus and identified DEGs. Secondly we used univariate Cox regression, Least absolute shrinkage and selection operator (LASSO) to screen the independent risk factors to construct nomogram in the training cohort. Thirdly, we evaluate its prediction accuracy via decision curves analysis (DCA), receiver operating characteristic (ROC) and calibration rate to confirm its performance on survival in training and validation cohort. Then we carried out subgroup analysis in training and validation to eliminate the effects of age, gender, and pathological subtype. Lastly, to verify feasibility of nomogram in practice, we applied immunohistochemistry to clinical samples and analyzed the relationship between IHC scores and prognosis.Results The 702 DEGs between 40 PTCLs and 20 non-tumor patients were identified. Then ANGPTL2, CPSF4, CLIC4 and OTUD6B were screened out as independent risk factors via univariate Cox regression and LASSO. The DCA, ROC, Harrell’s concordance index (c-index) and calibration rate showed nomogram predicting more accurately than any single specific transcript. The results showed PTCLs with higher nomogram-score had a longer survival, regardless of age, gender and pathological subtype. Finally, the high expression level of ANGPTL2, CPSF4 and OTUD6B related to poor prognosis. Higher expression of CLIC4 related to longer survival.Conclusion This nomogram showed the favorable clinical applicability, regardless of age, gender and pathological subtype.

Current Concepts in Nodal Peripheral T-Cell Lymphomas

This review summarizes the current understanding of mature T-cell neoplasms predominantly involving lymph nodes, including ALK-positive and ALK-negative anaplastic large cell lymphomas, nodal T-follicular helper cell lymphoma, Epstein-Barr virus-positive nodal T/NK-cell lymphoma, and peripheral T-cell lymphoma (PTCL), not otherwise specified. These PTCLs are clinically, pathologically, and genetically heterogeneous, and the diagnosis is made by a combination of clinical information, morphology, immunophenotype, viral positivity, and genetic abnormalities. This review summarizes the pathologic features of common nodal PTCLs, highlighting updates in the fifth edition of the World Health Organization classification and the 2022 International Consensus Classification.

An update on genetic aberrations in T-cell neoplasms

T-cell neoplasms are a highly heterogeneous group of leukaemias and lymphomas that represent 10-15% of all lymphoid neoplasms. Traditionally, our understanding of T-cell leukaemias and lymphomas has lagged behind that of B-cell neoplasms, in part due to their rarity. However, recent advances in our understanding of T-cell differentiation, based on gene expression and mutation profiling and other high throughput methods, have better elucidated the pathogenetic mechanisms of T-cell leukaemias and lymphomas. In this review, we provide an overview of many of the molecular abnormalities that occur in various types of T-cell leukaemia and lymphoma. Much of this knowledge has been used to refine diagnostic criteria that has been included in the fifth edition of the World Health Organization. This knowledge is also being used to improve prognostication and identify novel therapeutic targets, and we expect this progress will continue, eventually resulting in improved outcomes for patients with T-cell leukaemias and lymphomas.

Emerging predictive biomarkers for novel therapeutics in peripheral T-cell and natural killer/T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) and natural killer/T-cell lymphoma (NKTCL) are rare subtypes of non-Hodgkin's lymphoma that are typically associated with poor treatment outcomes. Contemporary first-line treatment strategies generally involve the use of combination chemoimmunotherapy, radiation and/or stem cell transplant. Salvage options incorporate a number of novel agents including epigenetic therapies (e.g. HDAC inhibitors, DNMT inhibitors) as well as immune checkpoint inhibitors. However, validated biomarkers to select patients for individualized precision therapy are presently lacking, resulting in high treatment failure rates, unnecessary exposure to drug toxicities, and missed treatment opportunities. Recent advances in research on the tumor and microenvironmental factors of PTCL and NKTCL, including alterations in specific molecular features and immune signatures, have improved our understanding of these diseases, though several issues continue to impede progress in clinical translation. In this Review, we summarize the progress and development of the current predictive biomarker landscape, highlight potential knowledge gaps, and discuss the implications on novel therapeutics development in PTCL and NKTCL.

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.

Controversies in the Front-Line Treatment of Systemic Peripheral T Cell Lymphomas

Systemic peripheral T cell lymphomas (PTCL) are a rare and clinically and biologically heterogeneous group of disorders with scarce and generally low-quality evidence guiding their management. In this manuscript, we tackle the current controversies in the front-line treatment of systemic PTCL including (1) whether CNS prophylaxis should be administered; (2) whether CHOEP should be preferred over CHOP; (3) what role brentuximab vedotin should have; (4) whether stem cell transplant (SCT) consolidation should be used and whether autologous or allogeneic; (5) how should molecular subtypes (including DUSP22 or TP63-rearranged ALCL or GATA3 or TBX21 PTCL, NOS) impact therapeutic decisions; and (6) whether there is a role for targeted agents beyond brentuximab vedotin.

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.

Primary Cutaneous Anaplastic Large-Cell Lymphoma With Aberrant CD20 Expression: Case Report and Review of the Literature

ABSTRACT

Cutaneous CD20 + T-cell lymphomas are exceedingly rare. Differentiating cases of T-cell lymphoma with aberrant expression of the B-cell marker CD20 from B-cell lymphoma may be associated with misdiagnosis or delays in diagnosis. We report, to the authors' knowledge, the first case of CD20 + primary cutaneous anaplastic large-cell lymphoma and review the literature to characterize published cases of CD20 + cutaneous T-cell lymphoma (n = 40). There is no accepted explanation for this phenomenon; however, it is suspected that these cases may be due to neoplastic transformation of CD20 + T cells or that CD20 may represent a T-cell activation marker. Expression of CD20 may have clinical significance in prognostication and consideration of treatment options with anti-CD20 therapies such as rituximab.

Genomic profiling for clinical decision making in lymphoid neoplasms

With the introduction of large-scale molecular profiling methods and high-throughput sequencing technologies, the genomic features of most lymphoid neoplasms have been characterized at an unprecedented scale. Although the principles for the classification and diagnosis of these disorders, founded on a multidimensional definition of disease entities, have been consolidated over the past 25 years, novel genomic data have markedly enhanced our understanding of lymphomagenesis and enriched the description of disease entities at the molecular level. Yet, the current diagnosis of lymphoid tumors is largely based on morphological assessment and immunophenotyping, with only few entities being defined by genomic criteria. This paper, which accompanies the International Consensus Classification of mature lymphoid neoplasms, will address how established assays and newly developed technologies for molecular testing already complement clinical diagnoses and provide a novel lens on disease classification. More specifically, their contributions to diagnosis refinement, risk stratification, and therapy prediction will be considered for the main categories of lymphoid neoplasms. The potential of whole-genome sequencing, circulating tumor DNA analyses, single-cell analyses, and epigenetic profiling will be discussed because these will likely become important future tools for implementing precision medicine approaches in clinical decision making for patients with lymphoid malignancies.

Effect of autologous hematopoietic stem cell transplantation for patients with peripheral T-cell lymphoma in China: A propensity score-matched analysis

BACKGROUND

The role of consolidation therapy with autologous stem cell transplantation (ASCT) in patients with peripheral T-cell lymphoma (PTCL) in first complete remission (CR1) or partial remission (PR1) remains controversial. The existing data from China are limited. Therefore, we aimed to investigate the effect of ASCT on the survival of Chinese patients with PTCL showing response to induction chemotherapy at our hospital.

METHODS

We retrospectively reviewed the data of patients with PTCL (excluding Natural killer/T cell lymphoma) in CR1 or PR1 treated at Peking University Hospital &Institute from 1996 to 2020. Propensity score matching (PSM) was used to balance clinical characteristics between the ASCT and non-ASCT groups. The primary endpoints were event-free survival (EFS) and overall survival (OS).

RESULTS

Of the 414 selected patients, 73 received ASCT consolidation and 341 did not. Over a median follow-up of 5.7 years, survival was significantly better in the ASCT group than in the non-ASCT group (median EFS, 8.1 years vs. 2.8 years, P = 0.002; median OS, 14.9 years vs. 10.2 years, P = 0.007). The 5-year EFS and OS rates were 68.4% and 77.0% in ASCT group, and 43.2% and 57.6% in non-ASCT group, respectively. The survival benefit was confirmed in the propensity score matched cohort (46 patients who received ASCT and 84 patients who did not receive ASCT): P = 0.007 for median EFS and P = 0.022 for the median OS. Cox regression analysis showed that ASCT was independently associated with better survival: hazard ratio (HR) for EFS, 0.46 (95% CI: 0.28-0.76); HR for OS, 0.50 (95% CI: 0.31-0.84). Subgroup analysis showed that ASCT was more likely to benefit higher-risk patients and those with advanced disease. Among the subtypes of PTCL, the benefit was significant in angioimmunoblastic T-cell lymphoma (HR = 0.26 [95% CI: 0.10-0.66] for EFS and 0.29 [95% CI: 0.12-0.74] for OS), but not in the other subtypes.

CONCLUSION

ASCT may improve the long-term survival of patients with PTCL in first CR or PR, especially for patients with angioimmunoblastic T-cell lymphoma. The specific groups most likely to benefit from upfront ASCT need to be clearly identified.

Immunohistochemical Approach to Genetic Subtyping of Anaplastic Large Cell Lymphoma

Anaplastic large cell lymphoma (ALCL) can be classified genetically based on rearrangements (R) of the ALK , TP63 , and/or DUSP22 genes. ALK- R defines a specific entity, ALK-positive ALCL, while DUSP22- R and TP63- R define subgroups of ALK-negative ALCLs with distinct clinicopathologic features. ALK -R and TP63 -R produce oncogenic fusion proteins that can be detected by immunohistochemistry. ALK immunohistochemistry is an excellent surrogate for ALK- R and screening with p63 immunohistochemistry excludes TP63- R in two third of ALCLs. In contrast, DUSP22 -R does not produce a fusion protein and its identification requires fluorescence in situ hybridization. However, DUSP22- R ALCL has a characteristic phenotype including negativity for cytotoxic markers and phospho-STAT3 Y705 . Recently, we also identified overexpression of the LEF1 transcription factor in DUSP22- R ALCL. Here, we sought to validate this finding and examine models for predicting DUSP22- R using immunohistochemistry for LEF1 and TIA1 or phospho-STAT3 Y705 . We evaluated these 3 markers in our original discovery cohort (n=45) and in an independent validation cohort (n=46) of ALCLs. The correlation between DUSP22- R and LEF1 expression replicated strongly in the validation cohort ( P <0.0001). In addition, we identified and validated a strategy using LEF1 and TIA1 immunohistochemistry that predicted DUSP22- R with positive and negative predictive values of 100% after exclusion of indeterminate cases and would eliminate the need for fluorescence in situ hybridization in 65% of ALK-negative ALCLs. This approach had similar results in identifying DUSP22- R in the related condition, lymphomatoid papulosis. Together with previous data, these findings support a 4-marker immunohistochemistry algorithm using ALK, LEF1, TIA1, and p63 for genetic subtyping of ALCL.

Hepatocyte phosphatase DUSP22 mitigates NASH-HCC progression by targeting FAK

Nonalcoholic steatohepatitis (NASH), a common clinical disease, is becoming a leading cause of hepatocellular carcinoma (HCC). Dual specificity phosphatase 22 (DUSP22, also known as JKAP or JSP-1) expressed in numerous tissues plays essential biological functions in immune responses and tumor growth. However, the effects of DUSP22 on NASH still remain unknown. Here, we find a significant decrease of DUSP22 expression in human and murine fatty liver, which is mediated by reactive oxygen species (ROS) generation. Hepatic-specific DUSP22 deletion particularly exacerbates lipid deposition, inflammatory response and fibrosis in liver, facilitating NASH and non-alcoholic fatty liver disease (NAFLD)-associated HCC progression. In contrast, transgenic over-expression, lentivirus or adeno-associated virus (AAV)-mediated DUSP22 gene therapy substantially inhibit NASH-related phenotypes and HCC development in mice. We provide mechanistic evidence that DUSP22 directly interacts with focal adhesion kinase (FAK) and restrains its phosphorylation at Tyr397 (Y397) and Y576 + Y577 residues, subsequently prohibiting downstream activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) cascades. The binding of DUSP22 to FAK and the dephosphorylation of FAK are indispensable for DUSP22-meliorated NASH progression. Collectively, our findings identify DUSP22 as a key suppressor of NASH-HCC, and underscore the DUSP22-FAK axis as a promising therapeutic target for treatment of the disease.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

Real-Life Experience Regarding Clinical Characteristics and Treatment Outcome in Non-Cutaneous Peripheral T-Cell Lymphomas: A Multicenter Study of the Turkish Hematology Research and Education Group (ThREG)

Objective:

Peripheral T-cell lymphomas (PTCLs) are an uncommon and quite heterogeneous group of disorders, representing only 10%-15% of all non-Hodgkin lymphomas. Although both molecular and clinical studies have increased in recent years, we still have little knowledge regarding real-life practice with PTCLs. In this study, we aimed to investigate the clinical characteristics and treatment outcomes of a large population-based cohort of patients presenting with systemic non-cutaneous PTCL.

Materials and Methods:

We conducted a multicenter retrospective analysis of 190 patients consecutively diagnosed and treated with non-cutaneous PTCLs between 2008 and 2016.

Results:

Considering all first-line treatment combinations, the overall response rate was 65.9% with 49.4% complete remission (n=81) and 16.5% partial response (n=27). The 5-year overall survival and event-free survival rates were significantly different between the transplant and non-transplant groups (p<0.01, and p=0.033, respectively).

Conclusion:

The retrospective analysis of a large volume of real-life data on the Turkish experience regarding non-cutaneous PTCL patients showed consistent results compared to other unselected PTCL cohorts with some minor differences in terms of survival and transplantation outcomes. The long-term outcome of patients who receive autologous hematopoietic cell transplantation as part of upfront consolidation or salvage therapy is favorable compared to patients who are unable to receive high-dose therapy.

Pathological and Molecular Features of Nodal Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are uncommon neoplasms derived from mature T cells or NK cells. PTCLs comprise numerous disease entities, with over 30 distinct entities listed in the latest WHO classification. They predominantly affect adults and elderly people and usually exhibit an aggressive clinical course with poor prognosis. According to their presentation, PTCLs can be divided into nodal, extranodal or cutaneous, and leukemic types. The most frequent primary sites of PTCLs are lymph nodes, with over half of cases showing nodal presentation. Nodal PTCLs include ALK-positive and ALK-negative anaplastic large cell lymphoma; nodal T-cell lymphoma with T follicular helper cell origin; and PTCL, not otherwise specified. Adult T-cell leukemia/lymphoma also frequently affects lymph nodes. Recent pathological and molecular findings in nodal PTCLs have profoundly advanced the identification of tumor signatures and the refinement of the classification. Therefore, the therapies and pathological diagnosis of nodal PTCLs are continually evolving. This paper aims to provide a summary and update of the pathological and molecular features of nodal PTCLs, which will be helpful for diagnostic practice.

Genetic alterations and oxidative stress in T cell lymphomas

T cell lymphomas encompass a diverse group of Non-Hodgkin lymphomas with a wide spectrum of clinical, immunological and pathological manifestations. In the last two decades there has been a progress in our understanding of the cell of origin, genetic abnormalities and their impact on behaviour in T cell lymphomas. Genetic alterations are one of the critical drivers of the pathogenesis of T cell lymphoma. Disease progression has been correlated with multiple genetic abnormalities where malignant clones arise primarily out of the host immune surveillance arsenal. There are many cellular processes involved in disease development, and some of them are T cell signaling, differentiation, epigenetic modifications, and immune regulation. Modulation of these crucial pathways via genetic mutations and chromosomal abnormalities possessing either point or copy number mutations helps tumor cells to develop a niche favourable for their growth via metabolic alterations. Several metabolic pathways especially regulation of redox homeostasis is critical in pathogenesis of lymphoma. Disruption of redox potential and induction of oxidative stress renders malignant cells vulnerable to mitochondrial damage and triggers apoptotic pathways causing cell death. Targeting genetic abnormalities and oxidative stress along with current treatment regime have the potential for improved therapeutics and presents new combination approaches towards selective treatment of T cell lymphomas.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

T-Cell Lymphomas, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphoproliferative disorders arising from mature T cells, accounting for about 10% of non-Hodgkin lymphomas. PTCL-not otherwise specified is the most common subtype, followed by angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma, anaplastic lymphoma kinase-positive, anaplastic large cell lymphoma, anaplastic lymphoma kinase-negative, and enteropathy-associated T-cell lymphoma. This discussion section focuses on the diagnosis and treatment of PTCLs as outlined in the NCCN Guidelines for T-Cell Lymphomas.

Genetic Landscape of Peripheral T-Cell Lymphoma

Peripheral T-Cell lymphoma (PTCL) comprises a heterogenous group of uncommon lymphomas derived from mature, post-thymic or “peripheral” T- and natural killer cells. The World Health Organization (WHO) emphasizes a multiparameter approach in the diagnosis and subclassification of these neoplasms, integrating clinical, morphologic, immunophenotypic, and genetic features into the final diagnosis. Clinical presentation is particularly important due to histologic, immunophenotypic and genetic variations within established subtypes, and no convenient immunophenotypic marker of monoclonality exists. In recent years, widespread use of gene expression profiling and next-generation sequencing (NGS) techniques have contributed to an improved understanding of the pathobiology in PTCLs, and these have been incorporated into the 2016 revised WHO classification of mature T- and NK-cell neoplasms which now encompasses nearly 30 distinct entities. This review discusses the genetic landscape of PTCL and its role in subclassification, prognosis, and potential targeted therapy. In addition to discussing T-Cell lymphoma subtypes with relatively well-defined or relevant genetic aberrancies, special attention is given to genetic advances in T-Cell lymphomas of T follicular helper cell (TFH) origin, highlighting genetic overlaps between angioimmunoblastic T-Cell lymphoma (AITL), follicular T-Cell lymphoma, and nodal peripheral T-Cell lymphoma with a TFH phenotype. Furthermore, genetic drivers will be discussed for ALK-negative anaplastic large cell lymphomas and their role in differentiating these from CD30+ peripheral T-Cell lymphoma, not otherwise specified (NOS) and primary cutaneous anaplastic large cell lymphoma. Lastly, a closer look is given to genetic pathways in peripheral T-Cell lymphoma, NOS, which may guide in teasing out more specific entities in a group of T-Cell lymphomas that represents the most common subcategory and is sometimes referred to as a “wastebasket” category.

Advances and Personalized Approaches in the Frontline Treatment of T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a rare and heterogenous subset of non-Hodgkin lymphoma characterized by an aggressive clinical course. Historically, the treatment of PTCLs have been analogous to that of aggressive B-cell lymphomas; however, it has been well-established that overall responses and complete remission rates are far inferior using near-identical chemotherapy strategies. Recently, there has been a plethora of newer agents designed to target distinguishing cellular and molecular features of specific PTCL subtypes. These agents have been proven to yield superior anti-lymphoma responses and, in some cases, overall survival in the relapsed, refractory, and frontline treatment setting. In this review, we will summarize and highlight the most influential clinical trials leading to the Food and Drug Administration (FDA) approval of several novel therapeutic agents against PTCL, with an emphasis on emerging studies and strategies to expand their potential use in the frontline treatment setting.

New Indications and platforms for CAR-T therapy in lymphomas beyond DLBCL

CD19 directed chimeric antigen receptor T-cell therapy (CAR-T) represents a significant advancement for patients with relapsed/refractory large B-cell lymphoma (LBCL). Long term follow-up confirms durable remissions in nearly half of the patients, a population which was previously estimated to have a median survival of around 6 months with standard salvage therapy. This initial success of CAR-T has led to significant expansion across other lymphoma histologies resulting in the recent regulatory approval of CAR-T in mantle cell lymphoma and follicular lymphoma. Additionally, multiple novel platforms of CAR-T therapy are under development to improve efficacy and limit toxicity such dual antigen targeting, allogeneic and natural killer CAR's. In this review, we focus on the new indications of CAR-T in lymphomas beyond LBCL as well as emerging platforms of CAR-T therapy.

The Leukemic Phase of ALK-Negative Anaplastic Large Cell Lymphoma Is Associated with CD7 Positivity, Complex Karyotype, TP53 Deletion, and a Poor Prognosis

Simple Summary

Anaplastic large cell lymphoma (ALCL) is a systemic peripheral T-cell neoplasm characterized by strong and uniform CD30 expression and, usually, the aberrant loss of one or more T-cell antigens. ALCL is further classified into anaplastic lymphoma kinase (ALK)-positive and ALK-negative types. ALCL rarely involves the peripheral blood. The reported leukemic phase ALCL cases are almost all pediatric patients with ALK-positive ALCL, which are frequently associated with the small cell morphology, t(2;5)(p23;q35), and a poorer prognosis. Leukemic phase ALK-negative ALCL is extremely rare, with approximately ten cases reported in the literature to date, mostly as single case reports. Here we report on nine patients with leukemic ALK-negative ALCL—the largest case series to date—and we compare these cases with 39 non-leukemic cases of ALK-negative ALCL. We show that the patients with leukemic ALK-negative ALCL have a greater frequency of absolute lymphocytosis, thrombocytopenia, bone marrow involvement, CD7 positivity, complex karyotype, TP53 deletion, and a dismal outcome. These data suggest that leukemic phase ALK-negative ALCL is associated with a number of poor prognostic factors and affected patients may need more aggressive treatment.

Abstract

Patients with anaplastic large cell lymphoma (ALCL) rarely develop a leukemic phase of the disease. The reported leukemic ALCL cases are almost all ALK-positive, which are frequently associated with small cell morphology, t(2;5)(p23;q35), and a poorer prognosis. Rare leukemic ALK-negative ALCL cases have been reported. In the present study, we investigated the clinical and pathologic features and outcomes of nine patients with leukemic ALK-negative ALCL and compared these features with 39 patients without leukemic disease. Compared with the non-leukemic ALK-negative ALCL group, patients with leukemic disease more often had absolute lymphocytosis (50% vs. 0%, p = 0.008), thrombocytopenia (60% vs. 11%, p = 0.03), bone marrow involvement (50% vs. 14%, p = 0.04), and CD7 positivity (71% vs. 19%, p = 0.02). Four of five (80%) patients with leukemic ALK-negative ALCL had a complex karyotype, which was significantly higher than that of the patients in the non-leukemic group. A fluorescence in situ hybridization for TP53 was performed on six leukemic ALK-negative ALCL cases and all (100%) had TP53 deletion. There were no significant differences in the other clinicopathologic features, treatment, and complete remission rates between patients in the leukemic versus non-leukemic group (all p > 0.05). The median follow-up of this cohort was 18 months with a range of 0.3–140 months. Eight of nine (90%) patients with leukemic ALK-negative ALCL died, and their overall survival was significantly shorter than that of the patients with non-leukemic disease (median 15.5 vs. 60 months, p = 0.001). In conclusion, we show that the leukemic phase of ALK-negative ALCL is associated with high-risk biologic features and, in particular, a complex karyotype and TP53 deletion. Compared with the non-leukemic ALK-negative ALCL patients, the patients with a leukemic phase of disease have poorer survival and may require more aggressive treatment.

Central nervous system ALK-negative anaplastic large cell lymphoma with IRF4/DUSP22 rearrangement

Anaplastic large cell lymphomas (ALCL) are mature T-cell neoplasms, approximately half of which harbor rearrangements of the ALK gene that confer a good prognosis. Recent studies have demonstrated that a significant proportion of ALK-negative ALCLs demonstrate rearrangements of the IRF4/DUSP22 locus that also are typically associated with a favorable prognosis. ALCL with primary involvement of the central nervous system (CNS) is extremely rare. We report what may be the first case of ALK-negative ALCL with IRF4/DUSP22 rearrangement involving the brain in a 55-year-old man. Magnetic resonance imaging demonstrated signal abnormalities in the periventricular region, corpus callosum and cingulate gyrus. Biopsy revealed a diffuse parenchymal and angiocentric infiltrate of CD30-positive cells that showed IRF4/DUSP22 rearrangement by fluorescence in situ hybridization. We also review the clinical and pathologic features of primary CNS ALK-negative ALCLs in the literature and highlight the need for awareness of this entity to optimize appropriate management.

Patch/plaque mycosis-fungoides-like presentations of DUSP22-translocated T-cell lymphomas

The DUSP22-IRF4 gene rearrangement results in downregulation of DUSP22, a presumed tumor suppressor in T-cell lymphomagenesis. It has been described in some cases of primary cutaneous and systemic anaplastic large-cell lymphoma, lymphomatoid papulosis, and transformed mycosis fungoides. Here we describe two patients with clinical lesions resembling patch/plaque mycosis fungoides that did not meet WHO criteria for large-cell transformation on histopathology yet showed a DUSP22 translocation. One patient who had a history of systemic anaplastic large-cell lymphoma with DUSP22 translocation presented with cutaneous involvement by his systemic lymphoma along with lymphomatoid papulosis and mycosis-fungoides-like lesions, all showing an identical immunophenotype and T-cell clone. These cases expand the spectrum of DUSP22-rearranged lymphomas to include mycosis-fungoides-like presentations without large-cell transformation.

ALK-Negative Anaplastic Large Cell Lymphoma (ALCL): Prognostic Implications of Molecular Subtyping and JAK-STAT Pathway

The anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a clinically distinct but heterogeneous entity and lacks the specific immunophenotypic or genetic features compared with the ALK-positive ALCL. Recent molecular studies have provided genetic landscapes of ALK-negative ALCL that have prognostic significance. In this study, we subtyped ALK-negative ALCL based on DUSP22 rearrangements and TP63 expression and also looked for mutations in JAK-STAT pathway. The subtyping of the ALK-negative ALCL in relation to DUSP22 rearrangement and TP63 expression was done using fluorescence in situ hybridization and immunohistochemistry, respectively. The hotspot JAK-STAT mutations were analyzed using Sanger sequencing and amplification refractory mutation system polymerase chain reaction (PCR) and Signal transducer and activator of transcription 3 (STAT3) expression by immunohistochemistry. Forty-eight cases of ALCL were included with median age of 30 years and sex ratio of 1.8:1. The p63 expression was detected in 26.7% of ALK-negative ALCL cases. DUSP22 rearrangement was noted in 12.5% cases of p63-negative ALK-negative ALCLs. DUSP22 rearranged cases had better overall survival in contrast to p63 expressing and triple negative ALCLs. Triple negative ALCLs showed inferior overall survival rate. STAT3 expression was evident in 61.1% and 60% of ALK-positive and ALK-negative ALCLs, respectively. None of the cases subjected to Sanger sequencing as well as amplification refractory mutation system PCR for hotspot mutation analysis of JAK1 (exon 24) and STAT3 (exon 21) revealed any mutation. ALK-negative ALCL is a genetically heterogeneous disease with widely disparate clinical outcomes. Subtyping of ALK-negative ALCL based on DUSP22 rearrangement and p63 expression provides prognostic information.

Cytokines, Genetic Lesions and Signaling Pathways in Anaplastic Large Cell Lymphomas

ALCL is a tumor of activated T cells and possibly innate lymphoid cells with several subtypes according to clinical presentation and genetic lesions. On one hand, the expression of transcription factors and cytokine receptors triggers signaling pathways. On the other hand, ALCL tumor cells also produce many proteins including chemokines, cytokines and growth factors that affect patient symptoms. Examples are accumulation of granulocytes stimulated by IL-8, IL-17, IL-9 and IL-13; epidermal hyperplasia and psoriasis-like skin lesions due to IL-22; and fever and weight loss in response to IL-6 and IFN-γ. In this review, we focus on the biology of the main ALCL subtypes as the identification of signaling pathways and ALCL-derived cytokines offers opportunities for targeted therapies.