CD30 Expression by B and T Cells: A Frequent Finding in Angioimmunoblastic T-Cell Lymphoma and Peripheral T-Cell Lymphoma-Not Otherwise Specified

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.

Pathobiology of nodal peripheral T-cell lymphomas: current understanding and future directions

Predominantly nodal is the most common clinical presentation of peripheral T- (and NK-) cell lymphomas (PTCL), which comprise three main groups of diseases: (i) systemic anaplastic large cell lymphomas (ALCL), whether positive or negative for anaplastic lymphoma kinase (ALK); (ii) follicular helper T-cell lymphomas (TFHL); and (iii) PTCL, not otherwise specified (NOS). Recent advances in the genomic and molecular characterization of PTCL, with enhanced understanding of pathobiology, have translated into significant updates in the latest 2022 classifications of lymphomas. ALK-negative ALCL is now recognized to be genetically heterogeneous, with identification of DUSP22 rearrangements in approximately 20-30% of cases, correlated with distinctive pathological and biological features. The notion of cell-of-origin as an important determinant of the classification of nodal PTCL is best exemplified by TFHL, considered as one disease or a group of related entities, sharing oncogenic pathways with frequent recurrent epigenetic mutations as well as a relationship to clonal hematopoiesis. Data are emerging to support that a similar cell-of-origin concept might be relevant to characterize meaningful subgroups within PTCL, NOS, based on cytotoxic and/or Th1 versus Th2 signatures. The small group of primary nodal Epstein-Barr virus-positive lymphomas of T- or NK-cell derivation, formerly considered PTCL, NOS, is now classified separately, due to distinctive features, and notably an aggressive course. This review summarizes current knowledge of the pathology and biology of nodal-based PTCL entities, with an emphasis on recent findings and underlying oncogenic mechanisms.

Brentuximab vedotin in treating Chinese patients with lymphoma: A multicenter, real-world study

BACKGROUND

Brentuximab vedotin (BV) was approved as a therapy for patients with CD30-positive lymphoma in China in 2020 based on the results of multiple clinical trails. Few Chinese real-world data of its use are yet available. Herein, we present the application situation of BV in patients with lymphoma among different hospitals in Henan province in China under real-world conditions.

METHODS

This was a multicenter and retrospective study in 104 patients with lymphoma who received BV for the first time between August 2020 and September 2022 across eight centers in Henan province. Data on the clinical use, effectiveness and adverse events (AEs) of BV were extracted from patient medical records. Short-term effectiveness was assessed based on objective response rate (ORR), complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD). Progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier method. Safety was also evaluated in our study.

RESULTS

104 lymphoma patients were enrolled in our study, who had completed a median of two cycles (range,1-8) of BV-based treatment. A total of 72.1% of patients were relapsed/refractory (R/R) lymphoma, and only 27.9% were previously untreated lymphoma who received BV in frontline treatment settings. Among them who received effectiveness evaluation, the ORR achieved 64.5% (CR 25.8%, PR 38.7%). After a median follow-up of 11 months, the 6-month PFS rate and OS rate achieved 77.2% and 90.1% respectively, and the 12-month PFS rate and OS rate achieved 77.2% and 79.9% respectively. In general, BV-based treatment was well-tolerated, with 38.5% incidence of grade ≥3 AEs. The most commonly reported AEs were hematologic disorders, especially neutropenia, with the incidence reaching 50.0%.

CONCLUSIONS

BV-based regimens could be a promising therapeutic option with remarkable effectiveness and moderate toxicity in treating Chinese lymphoma patients with CD30 expression.

CD30 in Cutaneous Pathology

ABSTRACT

The discovery of CD30 as a diagnostic marker was essential in the identification of not only some lymphomas but also many other solid tumors and benign reactive conditions. Many CD30+ cutaneous disorders and tumors have been categorized since the identification of the marker. With the design of targeted therapies against CD30+ tumoral cells, the interest in CD30 determination was not only diagnostic but also mainly therapeutic. In this article, we explore the historical aspects of the discovery of CD30 and examine the main CD30-related cutaneous pathology, susceptible of anti-CD30 modern treatments.

Pathologic and molecular insights in nodal T-follicular helper cell lymphomas

T-follicular helper (TFH) cells are one of the T-cell subsets with a critical role in the regulation of germinal center (GC) reactions. TFH cells contribute to the positive selection of GC B-cells and promote plasma cell differentiation and antibody production. TFH cells express a unique phenotype characterized by PD-1^hi, ICOS^hi, CD40L^hi, CD95^hi, CTLA^hi, CCR7^lo, and CXCR5^hi . Three main subtypes of nodal TFH lymphomas have been described: 1) angioimmunoblastic-type, 2) follicular-type, and 3) not otherwise specified (NOS). The diagnosis of these neoplasms can be challenging, and it is rendered based on a combination of clinical, laboratory, histopathologic, immunophenotypic, and molecular findings. The markers most frequently used to identify a TFH immunophenotype in paraffin-embedded tissue sections include PD-1, CXCL13, CXCR5, ICOS, BCL6, and CD10. These neoplasms feature a characteristic and similar, but not identical, mutational landscape with mutations in epigenetic modifiers (TET2, DNMT3A, IDH2), RHOA, and T-cell receptor signaling genes. Here, we briefly review the biology of TFH cells and present a summary of the current pathologic, molecular, and genetic features of nodal lymphomas. We want to highlight the importance of performing a consistent panel of TFH immunostains and mutational studies in TCLs to identify TFH lymphomas.

Best Practices in CD30 Immunohistochemistry Testing, Interpretation, and Reporting: An Expert Panel Consensus

CONTEXT.—

Although CD30 testing is an established tool in the diagnostic workup of lymphomas, it is also emerging as a predictive biomarker that informs treatment. The current definition of CD30 positivity by immunohistochemistry is descriptive and based on reactivity in lymphomas that are defined by their universal strong expression of CD30, rather than any established threshold. Challenges include inconsistencies with preanalytic variables, tissue processing, pathologist readout, and with the pathologist and oncologist interpretation of reported results.

OBJECTIVE.—

To develop and propose general best practice recommendations for reporting CD30 expression by immunohistochemistry in lymphoma biopsies to harmonize practices across institutions and facilitate assessment of its significance in clinical decision-making.

DESIGN.—

Following literature review and group discussion, the panel of 14 academic hematopathologists and 2 clinical/academic hematologists/oncologists divided into 3 working groups. Each working group was tasked with assessing CD30 testing by immunohistochemistry, CD30 expression readout, or CD30 expression interpretation.

RESULTS.—

Panel recommendations were reviewed and discussed. An online survey was conducted to confirm the consensus recommendations.

CONCLUSIONS.—

CD30 immunohistochemistry is required for all patients in whom classic Hodgkin lymphoma and any lymphoma within the spectrum of peripheral T-cell lymphoma are differential diagnostic considerations. The panel reinforced and summarized that immunohistochemistry is the preferred methodology and any degree of CD30 expression should be reported. For diagnostic purposes, the interpretation of CD30 expression should follow published guidelines. To inform therapeutic decisions, report estimated percent positive expression in tumor cells (or total cells where applicable) and record descriptively if nontumor cells are positive.

Response to Brentuximab Vedotin by CD30 Expression in Non-Hodgkin Lymphoma

Background

The safety and efficacy of brentuximab vedotin (BV), an antibody-drug conjugate directed to the CD30 antigen, has been assessed in several trials in patients with peripheral T-cell lymphoma (PTCL), cutaneous T-cell lymphoma (CTCL), or B-cell non-Hodgkin lymphoma (NHL). The objective of this research was to examine the relationship between CD30 expression level and clinical response to BV.

Patients and Methods

We analyzed response in patients treated with BV monotherapy in 5 prospective clinical studies in relapsed or refractory PTCL, CTCL, or B-cell NHL. CD30 expression was assessed by immunohistochemistry (IHC) using the Ber H2 antibody for 275 patients.

Results

Across all 5 studies, 140 (50.9%) patients had tumors with CD30 expression <10%, including 60 (21.8%) with undetectable CD30 by IHC. No significant differences were observed for any study in overall response rates between patients with CD30 expression ≥10% or <10%. Median duration of response was also similar in the CD30 ≥10% and <10% groups for all studies.

Conclusions

In this analysis of studies across a range of CD30-expressing lymphomas, CD30 expression alone, as measured by standard IHC, does not predict clinical benefit from BV, making the determination of a threshold level of expression uncertain.

CD30+ Lymphoproliferative Disorders as Potential Candidates for CD30-Targeted Therapies

CONTEXT.—

In the early 1980s, a monoclonal antibody termed Ki-1 was developed against a cell line derived from a patient with Hodgkin lymphoma. This antibody detected a limited number of benign activated lymphocytes in lymphoid tissue, whereas in Hodgkin lymphoma it appeared to be nearly specific for Reed-Sternberg cells and their mononuclear variants. Subsequent studies showed that Ki-1 expression defined a new type of lymphoma that was later designated anaplastic large cell lymphoma with or without anaplastic large cell kinase expression/translocation. In the past 30 years, numerous new lymphoma entities have been defined, many of which are variably positive for CD30. Many virally transformed lymphoproliferative disorders are also frequently positive for CD30.

OBJECTIVE.—

To illustrate the broad spectrum of CD30+ hematologic malignancies and to provide an update of CD30-targeted therapies.

DATA SOURCES.—

Personal experiences and published works in PubMed.

CONCLUSIONS.—

Because of its low expression in normal tissue, CD30 was studied as a therapeutic target for many years. However, the first functional humanized antibody against CD30 was developed only about 10 years ago. Brentuximab vedotin is a humanized anti-CD30 antibody linked to a cytotoxin, and was approved by the US Food and Drug Administration in 2012 for treating refractory Hodgkin lymphoma and anaplastic large cell lymphoma. Since then, the list of Food and Drug Administration-approved CD30-targeted hematologic malignancies has grown. Recently, the therapies using tumor antigen-specific chimeric antigen receptor T cells targeting CD30 have incited a great deal of enthusiasm and are studied in clinical trials.

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.

The Short-Term Efficacy and Safety of Brentuximab Vedotin Plus Cyclophosphamide, Epirubicin and Prednisone in Untreated PTCL: A Real-World, Retrospective Study

INTRODUCTION

Brentuximab vedotin (BV) showed high overall remission rates in refractory/relapsed classical Hodgkin's lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL). Although the efficacy of BV has been reported in clinical trials, its efficacy as a frontline therapy in real world for patients with CD30 positive subtypes of non-Hodgkin's lymphoma (NHL) such as peripheral T-cell lymphoma with T-follicular helper cell (TFH) phenotype (PTCL, TFH), anaplastic large-cell lymphoma (ALCL) and angioimmunoblastic T-cell lymphoma (AITL) in China has not been well documented.

METHODS

Analysis of a real-world, observational, retrospective case series in patients suffering from AITL, sALCL and peripheral T-cell lymphoma with T-follicular helper phenotype (PTCL-TFH) and other types of PTCL treated with BV in frontline treatment was conducted. The patients were given treatment from May 2020 till June 28, 2021. All patients were pathologically diagnosed to have PTCL before treatment and expressed CD30. Patients received BV (1.8 mg/kg) combined with CEP (cyclophosphamide, epirubicin, prednisone acetate every 3 weeks). The primary endpoint was objective response rates (ORR), and secondary endpoints were duration of response and incidence of adverse events (AEs). Exploratory endpoints such as progression-free survival (PFS) are discussed even though after such a short period.

RESULTS

Nineteen patients completed ≥ 1 cycles of BV-CEP treatment (16 cases completed ≥ 4 cycles, 3 cases only completed 1 cycle). Among them, the ORR reached 89.5% [CR 52.7%; partial response (PR) 36.8%]. In the ALCL group, CR reached 100% with the median duration of response of up to 8 months, while in the AITL group, the ORR was 75% and 2 patients had disease progression after treatment with BV + CEP. We also observed that BV-CEP may extend the PFS compared to traditional chemotherapy such as the CHOEP regimen (BV-CEP: not evaluable, CHOEP: 6.5 months), although the median follow-up was only 6.7 months. Adverse events (AEs), including incidence and severity of febrile neutropenia (26% patients in the BV-CEP group and 30% in the CHOEP group), were similar between groups. There was no incidence of AEs leading to treatment withdrawal or death under BV-CEP treatment.

CONCLUSION

BV is a promising treatment in patients with ALCL, AITL and PTCL-TFH in frontline treatment settings.

Recent Advances in Diagnosis and Therapy of Angioimmunoblastic T Cell Lymphoma

Angioimmunoblastic T cell lymphoma (AITL) is a common subtype of mature peripheral T cell lymphoma (PTCL). As per the 2016 World Health Organization classification, AITL is now considered as a subtype of nodal T cell lymphoma with follicular helper T cells. The diagnosis is challenging and requires a constellation of clinical, laboratory and histopathological findings. Significant progress in the molecular pathophysiology of AITL has been achieved in the past two decades. Characteristic genomic features have been recognized that could provide a potential platform for better diagnosis and future prognostic models. Frontline therapy for AITL was mainly depending on chemotherapy and the management of relapsed or refractory AITL is still unsatisfactory with a very poor prognosis. Upfront transplantation offers better survival. Novel agents have been introduced recently with promising outcomes. Several clinical trials of combinations using novel agents are underway. Herein, we briefly review recent advances in AITL diagnosis and the evolving treatment landscape.

SOHO State of the Art Updates and Next Questions: Pathology and Pathogenesis of Nodal Peripheral T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous and often clinically aggressive group of neoplasms derived from mature post-thymic T-lymphocytes. These neoplasms are rare and usually diagnostically challenging. Our understanding of the pathogenesis of PTCL is increasing and this improved knowledge is leading us to better molecular characterization, more objective and accurate diagnostic criteria, more effective risk assessment, and potentially better treatments. The focus of this paper is to present a brief overview of the current pathology criteria and molecular and genetic features of nodal peripheral T-cell lymphomas focusing on distinct genetically and molecularly defined subgroups that are being recognized within each major nodal PTCL category. It is expected that the molecular stratification will improve the diagnosis and will provide novel therapeutic opportunities (biomarker-driven and targeted therapies) that might benefit and change the outcomes of patients with these neoplasms.

Biology and Molecular Pathogenesis of Mature T-Cell Lymphomas

Peripheral T-cell lymphomas (PTCLs) constitute a highly heterogeneous group of hematological diseases with complex clinical and molecular features consistent with the diversity of the T-cell type from which they originate. In the past several years, the systematic implementation of high-throughput genomic technologies for the analysis of T-cell malignancies has supported an exponential progress in our understanding of the genetic drivers of oncogenesis and unraveled the molecular complexity of these diseases. Recent findings have helped redefine the classification of T-cell malignancies and provided novel biomarkers to improve diagnosis accuracy and analyze the response to therapy. In addition, multiple novel targeted therapies including small-molecule inhibitors, antibody-based approaches, and immunotherapy have shown promising results in early clinical analysis and have the potential to completely change the way T-cell malignancies have been treated traditionally.

Mycosis Fungoides and Sézary Syndrome: An Integrative Review of the Pathophysiology, Molecular Drivers, and Targeted Therapy

Simple Summary

In the last few years, the field of cutaneous T-cell lymphomas has experienced major advances. In the context of an active translational and clinical research field, next-generation sequencing data have boosted our understanding of the main molecular mechanisms that govern the biology of these entities, thus enabling the development of novel tools for diagnosis and specific therapy. Here, we focus on mycosis fungoides and Sézary syndrome; we review essential aspects of their pathophysiology, provide a rational mechanistic interpretation of the genomic data, and discuss the current and upcoming therapies, including the potential crosstalk between genomic alterations and the microenvironment, offering opportunities for targeted therapies.

Abstract

Primary cutaneous T-cell lymphomas (CTCLs) constitute a heterogeneous group of diseases that affect the skin. Mycosis fungoides (MF) and Sézary syndrome (SS) account for the majority of these lesions and have recently been the focus of extensive translational research. This review describes and discusses the main pathobiological manifestations of MF/SS, the molecular and clinical features currently used for diagnosis and staging, and the different therapies already approved or under development. Furthermore, we highlight and discuss the main findings illuminating key molecular mechanisms that can act as drivers for the development and progression of MF/SS. These seem to make up an orchestrated constellation of genomic and environmental alterations generated around deregulated T-cell receptor (TCR)/phospholipase C, gamma 1, (PLCG1) and Janus kinase/ signal transducer and activator of transcription (JAK/STAT) activities that do indeed provide us with novel opportunities for diagnosis and therapy.

In Situ Characterization of Follicular Helper CD4 T Cells Using Multiplexed Imaging

Follicular helper CD4 T (Tfh) cells play an essential role in the formation of germinal centers (GCs), where mature B cells proliferate, differentiate, and provide long-term protective humoral responses. Despite the extensive phenotypic characterization and identification of human Tfh cell subsets, their spatial positioning at tissue level is not well understood. Here, we describe a quantitative multiplexed immunofluorescence approach allowing for the comprehensive in situ characterization of Tfh cells in human tonsils and lymph nodes (LNs) from individuals with angioimmunoblastic T-cell lymphoma (AITL). We have developed eight multiplexed panels comprising a spectrum of Tfh cell markers, like PD-1, CXCR5, and ICOS, along with transcription factors (Bcl6, Tbet, GATA3), to assess their expression, frequencies, spatial distribution and co-localization in a quantitative manner. Combined analysis of relevant markers revealed the presence of several Tfh cell subsets at tissue level based on the differential expression of surface receptors, nuclear factors as well as their distinct localization within the follicular areas. Interestingly, we found a considerable amount of tonsillar Tfh cells expressing high levels of the Th2 regulator GATA3. The co-expression of GATA3, CXCR5, and BCL6, points to an important role of GATA3 for the generation of effector human Tfh cells. Furthermore, our data revealed significantly different Tfh cell profile signatures between health and disease. Therefore, our imaging platform generates meaningful information for the in situ characterization of human Tfh cells and could provide the base for future studies aiming to a comprehensive understanding of Tfh cell tissue heterogeneity.

Strategies for aggressive T-cell lymphoma: divide and conquer

The aggressive peripheral T-cell lymphomas (PTCLs) are a heterogenous group of uncommon lymphomas of mature T lymphocytes dominated by 3 subtypes: systemic anaplastic large-cell lymphoma, both anaplastic lymphoma kinase positive and negative; nodal PTCL with T-follicular helper phenotype; and PTCL, not otherwise specified. Although the accurate diagnosis of T-cell lymphoma and the subtyping of these lymphomas may be challenging, there is growing evidence that knowledge of the subtype of disease can aid in prognostication and in the selection of optimal treatments, in both the front-line and the relapsed or refractory setting. This report focuses on the 3 most common subtypes of aggressive PTCL, to learn how current knowledge may dictate choices of therapy and consultative referrals and inform rational targets and correlative studies in the development of future clinical trials. Finally, I note that clinical-pathologic correlation, especially in cases of T-cell lymphomas that may present with an extranodal component, is essential in the accurate diagnosis and subsequent treatment of our patients.

Pathology and Pathogenesis of T-Cell Lymphoma

Peripheral T cell lymphomas (PTCLs) are a heterogeneous and often clinically aggressive group of neoplasms derived from mature post-thymic T lymphocytes. These neoplasms are rare and usually diagnostically challenging. Our understanding of the pathogenesis of PTCL is increasing and this improved knowledge is leading us to better molecular characterization, more objective diagnostic criteria, more effective risk assessment, and potentially to better treatments for these neoplasms.

Brentuximab vedotin and its use in the treatment of advanced Hodgkin's lymphoma

Brentuximab vedotin (BV), a CD30-directed antibody-drug conjugate, is US FDA approved for treatment of classic Hodgkin lymphoma (cHL) after progression or relapse of at least two prior lines of chemotherapy or autologous stem cell transplantation, as consolidation therapy after autologous stem cell transplantation for high-risk patients and as a front-line therapy for previously untreated, advanced-stage cHL in combination with chemotherapy. BV is a well-tolerated treatment in previously heavily pretreated relapsed/refractory cHL and in treatment-naive patients. BV use, in combination with other antineoplastic agents for cHL, is under investigation in multiple prospective clinical trials.

A suggested immunohistochemical algorithm for the classification of T-cell lymphomas involving lymph nodes

T-cell lymphomas are a heterogeneous group of neoplasms derived from mature T lymphocytes. These neoplasms are uncommon and usually diagnostically challenging. The focus of this article is to suggest an immunohistochemistry-based, practical approach to assist in the diagnosis of nodal T-cell lymphomas. These neoplasms fall into two major groups: those with many CD30+ tumor cells (group A) and neoplasms that are negative or show only partial expression of CD30 (group B). The differential diagnosis of group A neoplasms mainly includes ALK+ anaplastic large-cell lymphoma (ALCL), ALK-negative ALCL, mycosis fungoides with CD30+ large-cell transformation, adult T-cell leukemia/lymphoma, extranodal T-cell lymphomas involving lymph nodes (usually regional), and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). Group B neoplasms also include two groups based on the presence or absence of T follicular helper (TFH) markers. Those neoplasms expressing at least 2 TFH markers include angioimmunoblastic T-cell lymphoma, nodal PTCL with a TFH phenotype, and follicular T-cell lymphoma. Neoplasms expressing ≤1 TFH marker can be further subdivided based on the expression of CD8 and cytotoxic markers and mainly include PTCL-NOS and a series of unusual subsets including primary Epstein-Barr virus-positive nodal natural killer/T-cell lymphoma, PTCL-NOS with a cytotoxic immunophenotype, and γ/δ T-cell lymphomas. Using this algorithmic approach, we suggest that the pathologist can establish a diagnosis for most nodal T-cell lymphomas encountered in daily practice.

Practical Approaches on CD30 Detection and Reporting in Lymphoma Diagnosis

While our understanding of the biology of CD30 in lymphoma continues to evolve, our need to detect and measure its expression at the protein level remains critically important for diagnosis and patient care. In addition to its diagnostic and prognostic utility, CD30 has emerged as a vehicle for drug targeting through the antibody-drug conjugate brentuximab-vedotin (BV). Given the numerous ways that CD30 is utilized and its emergence as a predictive/prognostic biomarker, pathologists must come to a general consensus on the best reporting structure and methodology to ensure appropriate patient care. In this manuscript, we review the indications for testing, various modalities for testing, technical challenges, pitfalls, and potential standards of reporting. The following questions will try to be addressed in the current review article: What defines a "POSITIVE" level of CD30 expression?; How do we evaluate and report CD30 expression?; What are the caveats in the evaluation of CD30 expression?

Complete Remission of Relapsed Hodgkin's Lymphoma following Brentuximab Vedotin and Gemcitabine Combination Therapy with Severe Hypotension as Possible Treatment-Related Adverse Event: A Case Report

A 40-year-old Asian female with heavily treated relapsed Hodgkin's lymphoma showed complete remission (CR) after receiving 8 cycles of brentuximab vedotin (BV) in combination with gemcitabine as 4th line treatment. The patient remained in CR at the 18-month post-treatment follow-up. She developed severe hypotension (50/36 mm Hg) with upper and lower limb petechiae and edema after the addition of gemcitabine on the 6th cycle of BV. This adverse event resolved after 3 days of treatment with vasopressor and high-dose corticosteroid. The addition of dexamethasone for the subsequent 2 cycles successfully prevented this adverse event from recurring.

Immunophenotyping of the PD-L1-positive cells in angioimmunoblastic T cell lymphoma and Hodgkin disease

Objective

Programmed death-1 (PD-1) and its ligand PD-L1 are now used as predictive biomarkers to guide clinical decisions. Precise characterization of PD-L1-positive cells may contribute to our knowledge of which patients derive benefit from the PD-L1 blockade therapy.

Results

To address this issue, we performed immunophenotyping of PD-L1-positive cells in Hodgkin lymphoma and in angioimmunoblastic T cell lymphoma (AITL) employing multiple immunofluorescent immunolabeling. We found that PD-L1-positive cells and PD-1-positive cells both in Hodgkin lymphoma and in AITL belong to two completely different cell lineages. In both lymphomas, PD-1 was found exclusively in T-lymphocytes, whereas PD-L1 was revealed in the tumor microenvironment cells including macrophages. PD-L1 was also detected in CD30-positive cells in Hodgkin lymphoma but not in AITL. The marker of B-cell lineage, CD20, was not detectable in PD-L1-positive cells both in AITL and in Hodgkin. Our study highlights the importance of comprehensive assessment of PD-1/PD-L1 regulatory pathways for employing PD-L1 as a predictive biomarker in clinical practice. PD-L1-antibody therapy is proven in Hodgkin lymphoma. Comparative immunophenotyping of the PD-1/PD-L1 axis provides a support for attempts to prove this principle also for AITL.

Update on peripheral T-cell lymphomas with T-helper phenotype: Are there too many subtypes?

Follicular helper T (T_FH) cells are the providers of T-cell help to B-cells in the development of germinal centers and for the generation of most class-switched antibodies. The markers most commonly associated with T_FH activity are IL21, IL4, CD40L, BCL6, SAP, CXCR5/CXCL13, and ICOS. T-cell lymphoma genomic studies have shown that different T-cell lymphoma types express signatures typical for T_FH cells, this including angioimmunoblastic T-cell lymphoma (AITL), a related condition termed peripheral T-cell lymphoma with T_FH phenotype and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder. Angioimmunoblastic T-cell lymphoma is a well-established entity, a clinically aggressive disease with a survival of 30% OS after 5 years. Molecular and clinical studies have confirmed this as a well-established clinicopathological entity with relatively specific gene mutations, including mutations found in hematopoietic precursor cells and others. Peripheral T-cell lymphoma with T_FH phenotype is an associated disorder with histology of PTCL but a T_FH phenotype, as defined by the expression of 2-3 immunohistochemical markers. Molecular studies on this entity are showing a partial overlap with AITL. Primary cutaneous CD4+ small/medium lymphoproliferative disorder is an entirely different process that takes place in the skin, showing frank cytologic atypia, monoclonal TCR rearrangement and T_FH phenotype in the context of a clinically benign lesion. Here we review the main clinical, molecular and diagnostic features of these three lymphoproliferative processes.

Approach to nodal-based T-cell lymphomas

Peripheral T-cell lymphomas (PTCLs) represent a heterogeneous group of uncommon malignancies derived from mature T cells and usually characterised by an aggressive clinical course. Their clinical presentation, localisation and pattern of dissemination are highly variable, but the majority of cases present as nodal diseases. The recently revised classification of lymphomas has incorporated many new molecular genetic data derived from gene expression profiling and next generation sequencing studies, which refine the definition and diagnostic criteria of several entities. Nevertheless, the distinction of PTCL from various reactive conditions, and the diagnosis of PTCL subtypes remains notably challenging. Here, an updated summary of the clinicopathological and molecular features of the most common nodal-based PTCLs (angioimmunoblastic T-cell lymphoma and other nodal lymphomas derived from follicular T helper cells, anaplastic large cell lymphomas and peripheral T-cell lymphoma, not otherwise specified) is presented. Practical recommendations in the diagnostic approach to nodal T-cell lymphoproliferations are presented, including indications for the appropriate use and interpretation of ancillary studies. Finally, we discuss commonly encountered diagnostic problems, including pitfalls and mimics in the differential diagnosis with various reactive conditions, and the criteria that allow proper identification of distinct PTCL entities.

The impact of JAK/STAT inhibitor ruxolitinib on the genesis of lymphoproliferative diseases

Background/aim

Ruxolitinib, a JAK/STAT signaling pathway inhibitor targeted drug, has been approved for the controlling of disease symptoms and splenomegaly in patients with myeloproliferative neoplastic diseases. Recently, it has been proposed that ruxolitinib-induced JAK/STAT pathway inhibition in myelofibrosis is associated with an elevated frequency of aggressive B-cell lymphomas. However, the biological basis and significance of this pharmacobiological adverse event is unknown. The aim of this bioinformatics study is to detect any possible confounding effects of ruxolitinib on the genesis of lymphoproliferative disorders.

Materials and methods

The gene expression data were retrieved from the E-MTAB-783 Cancer Genome Project database. Gene expression data for all available genes in 26 cell lines belonging to various types of lymphomas were chosen for use in this in silico analysis.

Results

We identified genes that were significant in developing resistance to ruxolitinib in lymphoma cell lines.

Conclusion

Based on the results of our present study, ruxolitinib may potentially lead to the pathological expression of the transcription factors important in lymphoma genesis, neoplastic commitment on the progenitor lymphoid cells, inhibition of repressor transcriptions protective for lymphoma development, inhibition of apoptosis, promotion of neoplastic proliferation, transcriptional activation, and proliferation of malignant neoplastic B cells.

Practical Treatment Approach for Angioimmunoblastic T-Cell Lymphoma

Patients with angioimmunoblastic T-cell lymphoma (AITL), one of the most common types of peripheral T-cell lymphoma (PTCL), typically present with advanced disease, systemic symptoms, and immune deregulation. Treatment can be challenging owing to frequent relapses after initial and subsequent therapy. The front-line treatment approach currently mirrors the approach used for other nodal PTCLs with cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy and consideration for autologous stem-cell transplant (SCT). In the relapsed and refractory settings, allogeneic SCT offers the chance for long-term remission. Choice of treatment of relapsed or refractory disease depends on whether an allogeneic SCT is planned. Agents with preferential activity in relapsed or refractory AITL include epigenetic modifiers such as histone deacetylase inhibitors and hypomethylating agents. Other targeted agents show promise in AITL, including brentuximab vedotin and phosphoinositide-3-kinase inhibitors. Ongoing studies are evaluating new potential targets for AITL, with particular focus on identifying markers of response and resistance. Additional studies are assessing incorporation of novel agents into the front-line treatment of AITL. These studies will lead to more individualized treatment approaches and, ultimately, improved outcomes for patients with AITL.

The Role of Activator Protein-1 (AP-1) Family Members in CD30-Positive Lymphomas

The Activator Protein-1 (AP-1) transcription factor (TF) family, composed of a variety of members including c-JUN, c-FOS and ATF, is involved in mediating many biological processes such as proliferation, differentiation and cell death. Since their discovery, the role of AP-1 TFs in cancer development has been extensively analysed. Multiple in vitro and in vivo studies have highlighted the complexity of these TFs, mainly due to their cell-type specific homo- or hetero-dimerization resulting in diverse transcriptional response profiles. However, as a result of the increasing knowledge of the role of AP-1 TFs in disease, these TFs are being recognized as promising therapeutic targets for various malignancies. In this review, we focus on the impact of deregulated expression of AP-1 TFs in CD30-positive lymphomas including Classical Hodgkin Lymphoma and Anaplastic Large Cell Lymphoma.

Understanding CD30 biology and therapeutic targeting: a historical perspective providing insight into future directions

CD30 is a member of the tumor necrosis factor receptor superfamily. It is characteristically expressed in certain hematopoietic malignancies, including anaplastic large cell lymphoma and Hodgkin lymphoma, among others. The variable expression of CD30 on both normal and malignant lymphoid cells has focused research efforts on understanding the pathogenesis of CD30 upregulation, its contribution to lymphomagenesis through anti-apoptotic mechanisms, and its effect on cell survival. Given the restriction of CD30 to certain tumor types, the logical extension of this has been to attempt to exploit it as a therapeutic target. The efficacy of naked anti-CD30 antibodies in practice was, however, modest. Moreover, combinations with bacterial toxins and radioimmunoconjugates have also had limited success. The development of the antibody-drug compound brentuximab vedotin (BV), however, has rejuvenated interest in CD30 as a tumor target. Phase I and II clinical trials in Hodgkin lymphoma, peripheral T-cell lymphoma, cutaneous T cell lymphoma, and even CD30-expressing B-cell lymphomas, have shown the compound is well tolerated, but more importantly, able to deliver meaningful disease control even in patients with multiply relapsed or refractory disease. FDA approval has been granted for its use in relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma. A recent phase III trial of BV in cutaneous T-cell lymphoma has confirmed its superiority to standard of care therapies. In this manuscript, we explore the history of CD30 as a tumor marker and as a therapeutic target, both in the laboratory and in the clinic, with a view to understanding future avenues for further study.

How I manage peripheral T-cell lymphoma, not otherwise specified and angioimmunoblastic T-cell lymphoma: current practice and a glimpse into the future

Peripheral T-cell lymphoma (PTCL), not otherwise specified (NOS) and angioimmunoblastic T-cell lymphoma (AITL) are the most frequent of more than 20 mature PTCL entities featuring a broad spectrum of morphological, immunophenotypic, molecular and clinical characteristics. Unfortunately, recent progress in understanding the (epi)genetic background of PTCL has not been met with similar advances in treatment. Thus, CHO(E)P [cyclophosphamide, doxorubicin, vincristine, and prednisone (plus etoposide)] remains standard first-line therapy. Patients without comorbidities achieving complete or partial remission proceed to autologous stem cell transplantation. With this approach about 50% of patients survive long-term. Patients relapsing after or progressing during first-line therapy have a dismal prognosis. They receive salvage gemcitabine-therapy followed by allogeneic transplantation whenever possible. After allografting, approximately half of the patients survive long-term; any other treatment is palliative. New drugs investigated in phase II studies achieved response rates between 10% and 30%; long-term remissions are the exception to the rule. While most new drugs are not licensed and not readily available, a plethora of other innovative drugs targeting (epi-)genetic abnormalities are in early development. These, together with combinations of new and old drugs, will hopefully increase response to first-line therapy, bridge more patients to transplantation, and finally improve prognosis for all patients with PTCL.

The Comparative Diagnostic Features of Canine and Human Lymphoma

The non-Hodgkin lymphomas (NHLs) are a heterogeneous family of lymphoid malignancies that are among the most common neoplasms of both dogs and humans. Owing to shared molecular, signaling, incidence, and pathologic features, there is a strong framework supporting the utilization of canine lymphoma as a comparative, large animal model of human NHL. In alignment with the biologic similarities, the current approach towards the diagnosis and classification of canine lymphoma is based upon the human World Health Organization guidelines. While this approach has contributed to an increasing appreciation of the potential biological scope of canine lymphoma, it has also become apparent that the most appropriate diagnostic philosophy must be multimodal, namely by requiring knowledge of microscopic, immunophenotypic, and clinical features before establishing a final disease diagnosis. This review seeks to illustrate the comparative similarities and differences in the diagnosis of canine lymphoma through the presentation of the microscopic and immunophenotypic features of its most common forms.