Hodgkin And Reed-Sternberg Research Articles

Pinpointing Functionally Relevant miRNAs in Classical Hodgkin Lymphoma Pathogenesis.

Classical Hodgkin lymphoma (cHL) is a hematological malignancy of B-cell origin. The tumor cells in cHL are referred to as Hodgkin and Reed-Sternberg (HRS) cells. This review provides an overview of the currently known miRNA-target gene interactions. In addition, we pinpointed other potential regulatory roles of microRNAs (miRNAs) by focusing on genes related to processes relevant for cHL pathogenesis, i.e., loss of B-cell phenotypes, immune evasion, and growth support. A cHL-specific miRNA signature was generated based on the available profiling studies. The interactions relevant for cHL were extracted by comprehensively reviewing the existing studies on validated miRNA-target gene interactions. The miRNAs with potential critical roles included miR-155-5p, miR-148a-3p, miR-181a-5p, miR-200, miR-23a-3p, miR-125a/b, miR-130a-3p, miR-138, and miR-143-3p, which target, amongst others, PU.1, ETS1, HLA-I, PD-L1, and NF-κB component genes. Overall, we provide a comprehensive perspective on the relevant miRNA-target gene interactions which can also serve as a foundation for future functional studies into the specific roles of the selected miRNAs in cHL pathogenesis.

Expression Patterns of GATA3 in Classical Hodgkin Lymphoma: A Clinico-Pathological Study.

GATA3 is a transcription factor involved in T-cell maturation and has been previously shown to be aberrantly overexpressed in malignant Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL). However, the immunophenotypes of the cell types expressing GATA3 have not been precisely characterized so far in cHL tissues. In this single-center retrospective cohort study we analyzed the expression patterns of GATA3 alone and in combination with B, T, NK or macrophage-associated markers in 73 cases with newly diagnosed cHL and investigated for a possible correlation with clinical and laboratory parameters. Immunohistochemistry (single and double) was performed using GATA3 alone and in combination with CD20, CD3, CD56, CD68, CD30 or CD15. Clinical and laboratory parameters were collected and correlated with the expression of GATA 3. GATA3 nuclear expression was found in HRS cells in 39/73 (54%) cases of cHL. The Nodular Sclerosis (NS) subtype showed the highest positivity rate (35/56, 63%), followed by mixed cellularity (MC; 4/14, 29%) and lymphocyte rich (LR; 0/3). Double immunostainings showed that GATA3 was expressed by CD30+ or CD15+ HRS cells and a few CD3+ T-cells, whereas GATA3 expression was not detected in CD20, CD56 or CD68+ cells. GATA3-negative cHL was significantly associated with unfavorable prognostic factors such as older age at diagnosis and increased levels of serum β2-microglobulin. The heterogenous expression patterns of GATA3 in HRS cells that were observed in a substantial proportion of cHL, mainly in the NS subtype, further support the biological heterogeneity of cHL.

Spatially Resolved Tumor Microenvironment Predicts Treatment Outcomes in Relapsed/Refractory Hodgkin Lymphoma.

About a third of patients with relapsed or refractory classic Hodgkin lymphoma (r/r CHL) succumb to their disease after high-dose chemotherapy followed by autologous stem-cell transplantation (HDC/ASCT). Here, we aimed to describe spatially resolved tumor microenvironment (TME) ecosystems to establish novel biomarkers associated with treatment failure in r/r CHL. We performed imaging mass cytometry (IMC) on 71 paired primary diagnostic and relapse biopsies using a marker panel specific to CHL biology. For each cell type in the TME, we calculated a spatial score measuring the distance of nearest neighbor cells to the malignant Hodgkin Reed Sternberg cells within the close interaction range. Spatial scores were used as features in prognostic model development for post-ASCT outcomes. Highly multiplexed IMC data revealed shared TME patterns in paired diagnostic and early r/r CHL samples, whereas TME patterns were more divergent in pairs of diagnostic and late relapse samples. Integrated analysis of IMC and single-cell RNA sequencing data identified unique architecture defined by CXCR5+ Hodgkin and Reed Sternberg (HRS) cells and their strong spatial relationship with CXCL13+ macrophages in the TME. We developed a prognostic assay (RHL4S) using four spatially resolved parameters, CXCR5+ HRS cells, PD1+CD4+ T cells, CD68+ tumor-associated macrophages, and CXCR5+ B cells, which effectively separated patients into high-risk versus low-risk groups with significantly different post-ASCT outcomes. The RHL4S assay was validated in an independent r/r CHL cohort using a multicolor immunofluorescence assay. We identified the interaction of CXCR5+ HRS cells with ligand-expressing CXCL13+ macrophages as a prominent crosstalk axis in relapsed CHL. Harnessing this TME biology, we developed a novel prognostic model applicable to r/r CHL biopsies, RHL4S, opening new avenues for spatial biomarker development.

Distinct Hodgkin lymphoma subtypes defined by noninvasive genomic profiling.

The scarcity of malignant Hodgkin and Reed-Sternberg cells hampers tissue-based comprehensive genomic profiling of classic Hodgkin lymphoma (cHL). By contrast, liquid biopsies show promise for molecular profiling of cHL due to relatively high circulating tumour DNA (ctDNA) levels1-4. Here we show that the plasma representation of mutations exceeds the bulk tumour representation in most cases, making cHL particularly amenable to noninvasive profiling. Leveraging single-cell transcriptional profiles of cHL tumours, we demonstrate Hodgkin and Reed-Sternberg ctDNA shedding to be shaped by DNASE1L3, whose increased tumour microenvironment-derived expression drives high ctDNA concentrations. Using this insight, we comprehensively profile 366 patients, revealing two distinct cHL genomic subtypes with characteristic clinical and prognostic correlates, as well as distinct transcriptional and immunological profiles. Furthermore, we identify a novel class of truncating IL4R mutations that are dependent on IL-13 signalling and therapeutically targetable with IL-4Rα-blocking antibodies. Finally, using PhasED-seq5, we demonstrate the clinical value of pretreatment and on-treatment ctDNA levels for longitudinally refining cHL risk prediction and for detection of radiographically occult minimal residual disease. Collectively, these results support the utility of noninvasive strategies for genotyping and dynamic monitoring of cHL, as well as capturing molecularly distinct subtypes with diagnostic, prognostic and therapeutic potential.

CAR-T Cell Therapy for Classical Hodgkin Lymphoma.

Classical Hodgkin lymphoma (cHL) is a malignancy characterized by the presence of Hodgkin and Reed-Sternberg (HRS) cells within a complex tumor microenvironment (TME). Despite advances in conventional therapies, a subset of cHL patients experience relapse or refractory disease, necessitating the exploration of novel treatment strategies. Chimeric antigen receptor T cell (CAR-T cell) therapy has emerged as a promising approach for the management of cHL, harnessing the power of genetically modified T cells to recognize and eliminate tumor cells. In this article, we provide an overview of the pathogenesis of cHL, highlighting the key molecular and cellular mechanisms involved. Additionally, we discuss the rationale for the development of CAR-T cell therapy in cHL, focusing on the identification of suitable targets on HRS cells (such as CD30, CD123, LMP1, and LMP2A), clonotypic lymphoma initiating B cells (CD19, CD20), and cells within the TME (CD123, CD19, CD20) for CAR-T cell design. Furthermore, we explore various strategies employed to enhance the efficacy and safety of CAR-T cell therapies in the treatment of cHL. Finally, we present an overview of the results obtained from clinical trials evaluating the efficacy of CAR-T cell therapies in cHL, highlighting their potential as a promising therapeutic option. Collectively, this article provides a comprehensive review of the current understanding of cHL pathogenesis and the rationale for CAR-T cell therapy development, offering insights into the future directions of this rapidly evolving field.

Genomic, Transcriptional, and Immunological Validation of Distinct Molecular Subtypes of Classic Hodgkin Lymphoma through Tissue-Based and Noninvasive Methods

Introduction: The scarcity of malignant Hodgkin and Reed-Sternberg (HRS) cells has hampered comprehensive genomic profiling of classic Hodgkin lymphoma (cHL) from tumor tissue. Multiple recent studies have demonstrated that plasma cfDNA profiling facilitates molecular characterization of cHL. Leveraging noninvasive genotypes and Latent Dirichlet Allocation, we recently defined 2 genetic cHL subtypes in a large international cohort comprising 366 patients including pediatric and adult patients of all ages (Alig et al., ASH 2022 and ICML 2023). Cluster H1 comprised ~2/3 of cases and was dominated by a high somatic mutational burden, and non-silent mutations in genes canonically involved in NF-κB, JAK/STAT and PI3K signaling as well as in B2M. Conversely, cluster H2 (~1/3 of cases) was primarily characterized by recurrent somatic copy number aberrations as well as mutations in TP53 and KMT2D. Herein, we validate these previously identified genetic subtypes in external datasets as well as through orthogonal methods including tissue-based and noninvasive transcriptional and immune profiling. Methods: To validate genetic cHL subtypes, we first leveraged public cHL genotypes from 61 patients obtained through whole genome/exome sequencing (WGS/WES) of flow-sorted HRS cells (Maura et al, Blood Cancer Disc. 2023). Using our previously locked down probabilistic classifier, we assigned the H1/H2 subtype, and then correlated cluster assignments with clinical variables. To explore transcriptional differences between genetic subtypes, we profiled baseline plasma samples (n=113) from the larger plasma genotyping cohort (n=293) using EPIC-Seq (Esfahani et al, Nat Biotechnol 2022), which allows for noninvasive gene expression profiling from cfDNA fragmentation patterns at transcription start sites. Further, we used SABER (Sworder, Cancer Cell 2023) to enumerate T-cell receptor (TCR) rearrangements in cfDNA (cfTCR, n=292). Finally, to assess subtype-specific immune infiltrate patterns, we profiled cHL tumor specimens using RNA-Seq (n=64), and applied CIBERSORTx. Results: Similar to observations in our cfDNA discovery cohort, H1 was found to be the more prevalent subtype in the external validation set comprising 56% of tumors, while 44% were classified as H2. Recurrence frequencies of genetic features were comparable to and significantly correlated with those from our plasma discovery cohort ( R S=0.59 [H1] and R S=0.63 [H2], P<0.001 each). Of note, when considering the whole genome space, the higher mutational burden of H1 tumors could be confirmed ( P<0.01), and this association was independent of the tumor EBV status. In agreement with the discovery cohort, the bimodal age distribution and increased EBV positivity of the H2 subtype could also be recapitulated (31% vs 6% EBV+, P<0.01). To explore transcriptional differences between H1/H2 subtypes, we took advantage of the plasma enrichment of HRS cell ctDNA and utilized EPIC-Seq to noninvasively infer expression of 1,676 targeted genes. Tracking signatures derived from scRNA-Sequencing in plasma samples, we found that both HRS cells and the cHL tumor microenvironment can be successfully profiled by EPIC-Seq. Strikingly, we found substantial enrichment of a cytokine response signature in H1 tumors, while T-cell activation was among the top upregulated signatures in H2 tumors ( Fig. A). Importantly, the T-cell signature found in H2 was accompanied by a higher abundance of T-cell clones as quantified by SABER in baseline plasma samples ( P<0.001, Fig. B). Notably, cfTCR fragment length profiles resembled the mutant ctDNA profiles, strongly suggesting a tumor origin of the TCR rearrangements detected in plasma. Lastly, immune cell deconvolution of bulk RNA-Seq specimens indicated a higher abundance of CD8+ T-cells in H2 tumors ( P<0.01), further confirming our prior observations. Conclusions: Collectively, these results serve to validate H1 and H2 as distinct cHL subtypes, to confirm the characteristic genotypes defining them, and recapitulate their distinctive associations with key clinical and pathological variables including age and EBV status. We further validate the subtypes using orthogonal methods revealing dominant cytokine driven signaling in H1. Conversely, H2 tumors, which largely lack B2M mutations, despite their lower mutational burden, are rather immunogenic triggering T-cell responses.

BET inhibitors induce NF-κB and E2F downregulation in Hodgkin and Reed–Sternberg cells

The prognosis of patients with relapsed and/or refractory classic Hodgkin lymphoma (cHL) continues to be poor. Therefore, there is a continuing need to develop novel therapies and to rationalize the use of target combinations. In recent years there has been growing interest in epigenetic targets for hematological malignancies under the rationale of the presence of common alterations in epigenetic transcriptional regulation. Since Hodgkin and Reed–Sternberg (HRS) cells have frequent inactivating mutations of the CREBBP and EP300 acetyltransferases, bromodomain and extra-terminal (BET) inhibitors can be a rational therapy for cHL. Here we aimed to confirm the efficacy of BET inhibitors (iBETs) using representative cell models and functional experiments, and to further explore biological mechanisms under iBET treatment using whole-transcriptome analyses. Our results reveal cytostatic rather than cytotoxic activity through the induction of G1/S and G2/M cell-cycle arrest, in addition to variable MYC downregulation. Additionally, massive changes in the transcriptome induced by the treatment include downregulation of relevant pathways in cHL disease: NF-kB and E2F, among others. Our findings support the therapeutic use of iBETs in selected cHL patients and reveal previously unknown biological mechanisms and consequences of pan-BET inhibition.

Unraveling the Immune Microenvironment in Classic Hodgkin Lymphoma: Prognostic and Therapeutic Implications.

Classic Hodgkin lymphoma (cHL) is a lymphoid neoplasm composed of rare neoplastic Hodgkin and Reed-Sternberg (HRS) cells surrounded by a reactive tumor microenvironment (TME) with suppressive properties against anti-tumor immunity. TME is mainly composed of T cells (CD4 helper, CD8 cytotoxic and regulatory) and tumor-associated macrophages (TAMs), but the impact of these cells on the natural course of the disease is not absolutely understood. TME contributes to the immune evasion of neoplastic HRS cells through the production of various cytokines and/or the aberrant expression of immune checkpoint molecules in ways that have not been fully understood yet. Herein, we present a comprehensive review of findings regarding the cellular components and the molecular features of the immune TME in cHL, its correlation with treatment response and prognosis, as well as the potential targeting of the TME with novel therapies. Among all cells, macrophages appear to be a most appealing target for immunomodulatory therapies, based on their functional plasticity and antitumor potency.

STING is Expressed by Hodgkin and Reed Sternberg (HRS) Cells in a Subset of Classical Hodgkin Lymphoma (cHL) and Correlates with Tumor Microenvironment and Immune Response

Introduction: Cytosolic DNA of exogenous or endogenous origin triggers activation of cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, that activates innate immune responses through activation of the adaptor protein STING. The latter, in turn, activates TBK1 and IKK kinases that, in turn, activate IRF3 and NF-κB transcription factors, which induce expression of interferons (IFNs), chemokines and cytokines involved in anti-tumor immune responses. The expression patterns of STING in Hodgkin and Reed-Sternberg (HRS) cells and the potential role of cGAS-STING pathway in anti-tumor immune responses in classical Hodgkin lymphoma (cHL) remain unknown to date. Methods: In this prospective study, STING expression was immunohistochemically analysed in a cohort of 52 previously untreated patients with cHL and available tissue for flow cytometry (FC) analysis and histology as well as available peripheral blood samples for FC. An arbitrary 10% cutoff was used for positivity in HRS. The in vitro system included 6 cHL cell lines (MDAV, L1236, L428, L540, HDLM2, KMH2). Gene (mRNA level) and protein expression/activation of cGAS-STING components at baseline and experimental conditions were analysed by quantitative RT-PCR (RT-qPCR) and Western blot, respectively. The cHL cell lines were treated with a STING agonist or were subjected to silencing of STING gene using transient transfection with specific STING siRNA construct. The gene expression of cGAS-STING-associated IFNs and cytokines, including IFN-β, CXCL10, IFN-γ, STING, and a control gene (GAPDH), was analysed with RT-qPCR. Results: STING was positive in HRS cells of cHL in 22 of 52 (42%) patients. STING positivity in HRS significantly correlated with lower numbers of STING+ T-lymphocytes (p < 0.0001) and CD3+ T-lymphocytes (p = 0.04) but higher numbers of CD20+ B-cells assessed by FC in the tissues. In peripheral blood samples assessed by FC at presentation, STING expression by HRS correlated with higher numbers of CD3+ T-cells (p = 0.005) but lower numbers of NK-cells (p = 0.02). STING expression did not correlate with clinical features at presentation, including age, gender, Ann Arbor stage, B-symptoms, tumor burden, bulky disease, anemia, or other hematologic values. STING expression at the mRNA and protein level was substantially higher in L1236, L428 and HDLM2 compared to other cHL cell lines. Treatment with STING agonists stimulated gene expression of IFN-β and/or CXCL10 at a variable level indicating functional cGAS-STING pathway in HRS. Knocking down STING gene resulted in dramatic increase in CXCL10 gene expression in cHL cells. Conclusions: STING is expressed by HRS in a subset of cHL and significantly correlates with the lymphocytic populations in the tumor microenvironment and peripheral blood. The cGAS-STING pathway is functional in HRS suggesting that STING agonists may have therapeutic implications in patients with cHL. Keywords: Diagnostic and Prognostic Biomarkers, Hodgkin lymphoma, Microenvironment No conflicts of interests pertinent to the abstract.

Proteomic profiling differentiates classic Hodgkin lymphoma with and without skeletal involvement at the time of diagnosis

Introduction: Classic Hodgkin lymphoma (cHL) is a highly curable disease, even in advanced stages. It is controversial whether bone involvement has a negative effect on overall- and progression-free survival in patients treated with intensive chemotherapy. cHL is characterized by a unique tumor microenvironment (TME) consisting of few, scattered neoplastic Hodgkin and Reed-Sternberg (HRS) cells, embedded in an abundant background of reactive immune and stromal cells. When cHL disseminates, the new disease sites also contain both HRS cells and TME cells. Whether cases that present with bone lesions, harbour specific TME features is unknown. We investigated protein expression in lymph node biopsies from cHL patients with and without skeletal involvement at diagnosis, using nano liquid chromatography—tandem mass spectrometry (nLC-MS/MS), to identify potential markers of skeletal disease. Methods: Protein expression patterns in pre-therapeutic formalin-fixed, paraffin-embedded lymphoma samples from 69 cHL patients diagnosed at Aarhus University Hospital, Denmark between 2009 and 2018 were analysed by nLC-MS/MS. Patients were grouped according to diagnostic 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT). FDG PET/CT scans were reviewed specifically for bone involvement. The study cohort included 50 patients with nodal cHL (n-cHL) and no skeletal involvement, and 19 patients with both skeletal and nodal disease (s-cHL). Results: We identified 2,298 proteins; comparison of the protein profiles between the s-cHL and n-cHL groups revealed 220 unique proteins significantly differentially expressed (p < 0.05) and with a fold change of at least 25%. Of these, 117 proteins were upregulated (fold change 1.25–3.94), and 103 were downregulated (fold change 0.44–0.80) in s-cHL. In hierarchal clustering based on an even higher significance threshold (p < 0.001), i.e., 25 significantly differentially expressed proteins, two clusters were observed: (i) a skeletal-group comprising 12 s-cHL and 4 n-cHL samples; and (ii) a nodal-group of 46 n-cHL and 7 s-cHL samples. Of particular interest among the differentially expressed proteins, we identified isocitrate dehydrogenase (IDH1) and WD repeat- and FYVE domain-containing protein 4 (WDFY4). This pattern of protein expression suggests disturbance in cytoplasmic NADPH production, antigen processing/presentation, and B-cell survival in cHL patients with skeletal involvement compared to those without. Conclusion: Our data show differential protein expression in cHL lymphoma tissues that correlate with the presence or absence of concomitant bone involvement at diagnosis. This indicates that certain biological pathways are affected among those presenting with disease disseminated to the skeletal system. The research was funded by: Department of Clinical Medicine, Aarhus University; Health Research Foundation of Central Denmark Region; Brødrene Hartmanns Foundation; Carl and Ellen Hertz Foundation; the Danish Lymphoma Group; Kong Christian den Tiendes Foundation; Torben and Alice Frimodts Foundation; Aase and Ejnar Danielsens Foundation; Foundation of 1870; Dagmar Marshalls Foundation; Merchant Einar Willumsen’s Memorial Foundation; Eva and Henry Frænkel’s Memorial Foundation; Master Carpenter Jørgen Holm and wife Elisa f. Hansen’s Memorial Grant. The Orbitrap Fusion Tribrid mass spectrometer was funded by A. P. Møller og Hustru Chastine Mc-Kinney Møllers Fond til Almene Formaal. Keywords: Genomics, Epigenomics, and Other -Omics, Hodgkin lymphoma, Microenvironment No conflicts of interests pertinent to the abstract.

Abstract 939: Genomic characterization of PMBCL, cHL and DLBCL utilizing tissue and liquid biopsies

Abstract Background: Primary mediastinal large B-cell lymphoma (PMBCL), arising from thymic medullary B cells, shares molecular features with classic Hodgkin lymphoma (cHL), including activation of JAK/STAT and Nuclear Factor Kappa B (NF-ƙB) pathways, as well as PD-L1 mediated immune evasion. Much of the molecular characterization relied on availability of tissue samples. Cell-free DNA (cfDNA) has emerged as a promising non-invasive approach for molecular profiling in lymphomas. In this study, we characterized the molecular features of PMBCL and cHL in the Chinese population utilizing both tissue-based and liquid biopsies. Methods: Tissue and/or plasma samples from a total of 35 PMBCL patients, 52 cHL patients and 81 DLBCL patients that were subjected to targeted next-generation sequencing (NGS) using a 475 cancer-related gene panel were included in the analysis. Results: Analysis of matched tumor and plasma samples from 38 cHL patients revealed 152 (28.10%) overlapping genetic alterations, with a higher number of mutations detected in the plasma compared to tissue (Total=472 vs. 221; Median=11 vs. 3 per patient, P&amp;lt;0.01). Of these, 320 (59.15%) were unique to the plasma, whereas 69 (12.15%) were only found in the tissue. Mutant allele frequencies (MAFs) were also lower in the tissue than in the plasma, with a median of 1.71% vs 2.99% (P&amp;lt;0.01). In 18 PMBCL patients, who had paired plasma and tumor samples, similar number of genetic alterations were detected (Total=347 vs. 411; Median=19.5 vs. 21 per patient, P=0.09). Of these, 273 (56.29%) alterations were shared variants, 74 (15.28%) were unique to the plasma sample and 138 (28.45%) were unique to the tissue. MAFs were higher in the tissue compared with the plasma (23.35% vs. 8.78%, P&amp;lt;0.01). Comparisons of mutational profiles among PMBCL, cHL, and DLBCL showed similar mutational profiles between PMBCL and cHL. The most frequently detected genetic alterations in PMBCL and cHL were STAT6 (68.57% vs. 40.38%), SOCS1 (57.14% vs. 57.69%), ACTB (48.57% vs. 23.08%), B2M (48.57% vs. 42.31%), and TNFAIP3 (34.29% vs. 40.38%). On the contrary, the frequencies of STAT6 (68.57% vs. 6.17%, P &amp;lt;0.01), SOCS1 (57.14% vs. 18.52%, P&amp;lt;0.05), and ACTB (48.57% vs. 9.88%, P&amp;lt;0.05) were markedly different comparing PMBCL and DLBCL. Meanwhile, the more common genetic alterations in DLBCL, such as MYD88 (33.33% vs. 0.00%, P&amp;lt;0.01), BCL6 (33.33% vs. 11.43%, P=0.06), BCL2 (20.99% vs. 2.86%, P&amp;lt;0.05), and CDKN2A (24.69% vs. 2.86%, P&amp;lt;0.05) were rarely detected in PMBCL patients. Conclusion: Our findings support that ctDNA in PMBCL and cHL may be an attractive source of genetic materials to assess tumor genomics and guide treatment decisions, especially in cHL with only 1% Hodgkin and Reed/Sternberg (HRS) cells. We also demonstrate for the first time in the Chinese population that PMBCL and cHL shared comparable mutational profiles, which were different from that of DLBCL. Citation Format: Xiaonan Wang, Lu Shen, Liuqing Zhu, Jiani C. Yin, Haimeng Tang, Yang Shao. Genomic characterization of PMBCL, cHL and DLBCL utilizing tissue and liquid biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 939.

Classic Hodgkin Lymphoma with Marked Granulomatous Reaction: A Clinicopathologic Study of 20 Cases.

Granulomatous reactions can be associated with various types of lymphoma, most commonly classic Hodgkin lymphoma (CHL). In some cases, the granulomatous reaction is extensive, obscuring the presence of neoplastic cells and potentially leading to delayed diagnosis and treatment. It is unknown if this subgroup of CHL has any clinicopathologic features. Here, we assessed the clinical and pathological features of 20 cases of CHL with a marked granulomatous reaction, defined in this study as granulomas representing > 50% of the total cellularity/space of the specimen. This cohort of patients showed a male predominance (M:F ratio = 1.9:1) and 75% of patients were older than 40 years. Nineteen (95%) patients presented with lymphadenopathy with the neck/supraclavicular areas being most commonly involved (11/19; 58%). Advanced stage (III-IV) disease and B symptoms were present in 69% and 64% of patients, respectively. The morphologic features of these neoplasms fit best with mixed cellularity type. The Hodgkin and Reed-Sternberg (HRS) cells were positive for CD30, PAX5 (weak), pSTAT3 (80%), CD15 (70%), PD-L1 (67%), EBV-encoded small RNA (EBER)/LMP1 (50%) and CD20 (42%), and were negative for CD3, CD5, CD45, ALK and pERK. The histiocytes of the granulomas were positive for PD-L1 (67%), pSTAT3 (50%), and were negative for pERK and cyclin D1. Next generation sequencing using a 162-gene panel was negative for mutations in 4 cases. With a median follow-up of 58.9 months (range, 3.4-199.2 months), the median overall survival was 111.0 months and the 5-year overall survival was 78%. In summary, patients with CHL and a marked granulomatous reaction can present a diagnostic challenge and the pathologist must be alert to the possible presence of CHL to avert potential misdiagnosis. The histiocytes in the granulomas frequently express PD-L1, likely through the activation of JAK2/STAT3 pathway, suggesting a potential role for PD-1 blockade therapy in these patients.

Hodgkin lymphoma in the bone marrow aspirate of a young patient with human immunodeficiency virus.

eJHaemEarly View HAEMATOLOGY IMAGESOpen Access Hodgkin lymphoma in the bone marrow aspirate of a young patient with human immunodeficiency virus Evashin Pillay, Corresponding Author Evashin Pillay evashinp@gmail.com orcid.org/0000-0003-0733-2860 University of KwaZulu-Natal & National Health Laboratory Service, Inkosi Albert Luthuli Central & King Edward VIII Hospitals, Durban, South Africa Correspondence Evashin Pillay, Department of Haematology, Inkosi Albert Luthuli Central Hospital, 4th Floor Laboratory Building, 800 Bellair Road, Durban 4091, KwaZulu-Natal, South Africa. Email: evashinp@gmail.comSearch for more papers by this authorPoobalan Naidoo, Poobalan Naidoo University of KwaZulu-Natal & KwaZulu Natal Provincial Department of Health, Inkosi Albert Luthuli Central & King Edward VIII Hospitals, Durban, South AfricaSearch for more papers by this author Evashin Pillay, Corresponding Author Evashin Pillay evashinp@gmail.com orcid.org/0000-0003-0733-2860 University of KwaZulu-Natal & National Health Laboratory Service, Inkosi Albert Luthuli Central & King Edward VIII Hospitals, Durban, South Africa Correspondence Evashin Pillay, Department of Haematology, Inkosi Albert Luthuli Central Hospital, 4th Floor Laboratory Building, 800 Bellair Road, Durban 4091, KwaZulu-Natal, South Africa. Email: evashinp@gmail.comSearch for more papers by this authorPoobalan Naidoo, Poobalan Naidoo University of KwaZulu-Natal & KwaZulu Natal Provincial Department of Health, Inkosi Albert Luthuli Central & King Edward VIII Hospitals, Durban, South AfricaSearch for more papers by this author First published: 13 March 2023 https://doi.org/10.1002/jha2.670AboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat A 31-year-old South African lady, HIV-positive since 2019 (medication: fixed dose combination antiretroviral therapy – tenofovir, lamivudine and dolutegravir; CD4 count: 328 cells/µL; HIV viral load: undetectable) and who completed a full course of empiric therapy for tuberculosis (TB) 2 months prior, presented to the emergency room complaining of fatigue, loss of appetite and malaise; no bleeding. During admission, her general examination was remarkable for muscle wasting, tachycardia, pallor, pyrexia (>38°C) and generalised significant lymphadenopathy (LAD), particularly evident as a left-sided axillary mass. Systemic examination revealed a distended abdomen compatible with ascites, and reduced bi-basal breath sounds; no hepatosplenomegaly. The overall clinical impression was that of a young female with stage 4 HIV and features of lymphoma, as supported by constitutional symptoms, LAD and serositis. Blood work comprising an FBC demonstrated an isolated severe anaemia (leucocytes 5.20 × 109/L – lymphocytes 7%, haemoglobin 5.1 g/dL and platelets 314 × 109/L); corrected reticulocyte count 0.45%. A staging CT (computed tomography) scan demonstrated generalised significant LAD (>1 cm; neck, supraclavicular, axillary (largest; >4 cm in short axis), mediastinal, hilar and para-aortic), bilateral pleural effusions with bi-basal atelectasis, gross ascites and hepatomegaly (±14 cm in span); no splenomegaly but multiple non-enhancing round hypodensities were noted in the spleen. Tissue biopsies were then planned, and the excision node histology confirmed a diagnosis of nodular sclerosis classic Hodgkin lymphoma (cHL), syncytial variant. A subsequent staging bone marrow (BM) biopsy was performed and remarkably, the BM aspiration smears revealed ∼5% large- and giant-sized, mono- and multi-nuclear tumour cells that morphologically resembled Hodgkin and Reed–Sternberg (HRS) cells (Figure 1). Unfortunately, several attempts to process the BM aspirate sample for flow cytometry proved unsuccessful due to repeated clogging of the sample injection tube. Nonetheless, the corresponding BM trephine biopsy sections showed focal infiltration by neoplastic cells, in addition to many pleomorphic counterparts (Figure 2). Immunohistochemical and special stains (Figure 2) revealed the HRS cells to express the following phenotype: CD45−, CD15+, CD30+, PAX5+, MUM1+, EBER+ (Epstein–Barr virus-encoded RNA), CD3−, CD20−, CD138−, ALK− and AE1/AE3−. Moreover, identifiable in close proximity to the HRS cells were a pathognomonic mixed population of inflammatory cells (Figures 1 and 2). Trilinear haematopoiesis was relatively adequately preserved. FIGURE 1Open in figure viewer Bone marrow aspirate smear (panels A–I; May–Grünwald–Giemsa; 100× objective). Morphologically heterogeneous tumour cells including Hodgkin cells (panels A–C; white arrows), forms undergoing cell division (panel D; yellow arrow), Reed–Sternberg cells (panels E–H; black arrows) and multi-nuclear counterparts (panel I; purple arrow) comprised of abundant, deeply basophilic, agranular cytoplasm with vacuolation and clasmatosis (pseudopod formation), and containing nuclei with irregular borders, reticulated chromatin, conspicuous nucleoli (panel A) and vacuolation (panels C, F and I). Inflammatory cells comprising eosinophils (panel B; pink arrow), granulocytes (panel C; green arrow), plasma cells (panel E; red arrow) and lymphocytes (panel I; cyan arrow) in close proximity to tumour cells. FIGURE 2Open in figure viewer Bone marrow trephine sections (panels A–I; 100× objective). Hodgkin cells (panels A and B; haematoxylin and eosin [H&E]; white arrows), Reed–Sternberg cells (panels B–E; H&E black arrows) and multi-nuclear tumour cell variants (panels C, E and F; H&E purple arrows). A lacunar cell (panel A; white arrow), hallmark-like cell (panel B; blue arrow) and mitotic Reed–Sternberg cell with ‘cherry-red’ nucleoli (panel D; yellow arrow). Immunostaining of tumour cells for CD15 (panel G; black arrow), CD30 (panel H; black arrow) and Epstein–Barr virus-encoded RNA (EBER) (panel I; in situ hybridisation [ISH]; black arrow). Inflammatory cells comprising eosinophils (panel A; pink arrow), plasma cells (panel A; red arrow), granulocytes (panel B; green arrow) and lymphocytes (panel B; cyan arrow) in close proximity to tumour cells. Finally, an international prognostic score of 4 was concluded (serum albumin 1.3 g/dL, haemoglobin 5.1 g/dL, stage IV disease and lymphocytes 7%). Notably, microbiological investigations for SARS-CoV-2 and TB were negative. Unfortunately, the patient succumbed to a hospital-acquired pneumonia despite exhaustive supportive therapy and empiric antibiotics, and prior to initiating chemotherapy. It is exceedingly rare to observe well preserved HRS cells in a BM aspirate film. The accompanying fibrotic milieu of the infiltrated BM probably causes tumour cell fragmentation and/or impairs their effective aspiration [1-4]. Another consideration is that of scattered focal bony lesions which may not be biopsied during the process of attempting aspiration [5, 6]. This case highlights an exceptional clinicopathologic entity by demonstrating HRS cells in the BM aspirate film of a young HIV-positive patient presenting with the syncytial variant of nodular sclerosis cHL. It has enabled careful examination of numerous HRS cells thereby contributing to appreciation of their morphological heterogeneity. Haemato-pathologists should be cognizant of such cases to prevent misdiagnosis as metastatic non-haematological neoplasms (particularly carcinoma) or other haematological neoplasms (particularly non-Hodgkin lymphoma) [7, 8]. Accordingly, timeous diagnosis may prove to be lifesaving, especially in resource-constrained settings. ACKNOWLEDGEMENTS The authors thank the hospital administrative and laboratory staff for their assistance in preparing this case. Verbal consent was duly obtained from the patient for purposes of publication. CONFLICT OF INTEREST STATEMENT The authors declare no conflict of interest. ETHICS STATEMENT Ethical approval was obtained from the Biomedical Research Ethics Committee (BREC) affiliated with the University. Open Research DATA AVAILABILITY STATEMENT The data that support the findings of this study are available from the corresponding author upon reasonable request. REFERENCES 1Swart L, Shuttleworth MH, Opie JJ, van Schalkwyk W. Paediatric Hodgkin lymphoma with Reed-Sternberg and mononuclear Hodgkin cells in the bone marrow aspirate. Br J Haematol. 2012; 157: 2. 2Xu Z, Burns BF, Faught C. Reed-Sternberg cells detected in the bone marrow aspirate in a young patient with nodular sclerosis Hodgkin lymphoma. Eur J Haematol. 2013; 92: 365– 6. 3Parsons K, Leach M, Bain BJ. Hodgkin lymphoma in a bone marrow aspirate. Am J Hematol. 2020; 95: 328– 9. 4Domínguez-Muñoz MÁ, Morales-Camacho RM, Prats-Martín C, Ávila R, Vargas MT, Burillo S, et al. Unusual co-occurrence of Hodgkin lymphoma and hemophagocytic lymphohistiocytosis in a bone marrow aspirate. Ann Hematol. 2016; 95: 1019– 21. 5Lee S-G, Paik S-Y, Sohn H-J, Kim SY, Kong S-Y. Numerous Reed-Sternberg cells in bone marrow aspirate from a patient with syncytial variant of nodular sclerosis classical Hodgkin lymphoma. Int J Hematol. 2015; 101: 107– 8. 6Kini JR, Suresh PK, Sinha R, Sahu K, Kumar S, Prasad K. Value of bone marrow examination in Hodgkin lymphoma: report of three cases with review of literature. J Cancer Res Ther. 2012; 8(3): 457– 9. 7Strickler JG, Michie SA, Warnke RA, Dorfman RF. The “syncytial variant” of nodular sclerosing Hodgkin's disease. Am J Surg Pathol. 1986; 10(7): 470– 7. 8Conlin PA, Blann MM, Morgan DL. Pathologic quiz case: supraclavicular lymphadenopathy in a 30-year-old man. Arch Pathol Lab Med. 2000; 124: 1837– 8. Early ViewOnline Version of Record before inclusion in an issue FiguresReferencesRelatedInformation

Genetic abnormalities assist in pathological diagnosis and EBV-positive cell density impact survival in Chinese angioimmunoblastic T-cell lymphoma patients.

To explore the application of genetic abnormalities in the diagnosis of angioimmunoblastic T-cell lymphoma (AITL) and the reliable pathological prognostic factors. This study included 53 AITL cases, which were reviewed for morphological patterns, immunophenotypes, presence of Hodgkin and Reed-Sternberg (HRS)-like cells, and co-occurrence of B cell proliferation. The Epstein-Barr virus (EBV)-positive cells in tissues were counted, and cases were classified into "EBV encoded RNA (EBER) high-density" group if >50/HPF. Targeted exome sequencing was performed. Mutation data can assist AITL diagnosis: 1) with considerable HRS-like cells (20 cases): RHOA mutated in 14 cases (IDH2 co-mutated in 3 cases, 4 cases with rare RHOA mutation), TET2 was mutated in 5 cases (1 case co-mutated with DNMT3A), and DNMT3A mutated in 1 case; 2) accompanied with B cell lymphoma (7 cases): RHOA mutated in 4 cases (1 case had IDH2 mutation), TET2 mutated in 2 cases and DNMT3A mutated in 1 case; 3) mimic peripheral T cell lymphoma, not otherwise specified (5 cases): RHOA mutated in 2 cases (IDH2 co-mutated in 1 case), TET2 mutated in 3 cases, and DNMT3A mutated in 1 case; 4) pattern 1 (1 case), RHOA and TET2 co-mutated. Besides RHOAG17V (30/35), rare variant included RHOAK18N, RHOAR68H, RHOAC83Y, RHOAD120G and RHOAG17del, IDH2R172 co-mutated with IDH2M397V in one case. There were recurrent mutations of FAT3, PCLO and PIEZO1 and genes of epigenetic remodeling, T-cell activation, APC and PI3K/AKT pathway. EBER high-density independently indicated adverse overall survival and progression-free survival (P=0.046 and P=0.008, Kaplan-Meier/log-rank). Over half AITL cases might be confused in diagnosis for certain conditions without mutation data. Targeted exome sequencing with a comprehensive panel is crucial to detect both hot-spot and rare mutation variants for RHOA and IDH2 and other recurrent mutated genes in addition to TET2 and DNMT3A. EBER high-density independently indicated adverse survival.

IL-6 as an Inflammatory Marker in Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a lymphoid tumor that develops from embryological or post-germinal center B-cells. The disease was originally recognized in 1832 by Thomas Hodgkin. Globally, 0.4% of clinically diagnosed cancers in 2018 were caused by HL. Regardless of age, ethnicity, or location, the prevalence of HL varies. It's a particular kind of malignant tumor in which the cancerous Hodgkin and Reed-Sternberg (HRS) cells are surrounded by a significant cellular infiltration of immune cells (lymphocytes, macrophages, eosinophils, mast cells, plasma cells, and collagen cells), which also contribute to the microenvironment of the tumor. Numerous chemotherapy drugs and low-dose field radiation have been found to significantly reduce illness mortality [1].&#x0D; High levels of cytokines that stimulate the immune system, such as interleukin (IL)-6, tumor necrosis factor (TNF), and eotaxin are produced by developing tumor cells and/or by reactive immune cells associated with tumors. These markers are anticipated to promote B-cell activation and related high-risk DNA-modifying activities, which will lead to the growth of B-cell lymphoma. IL-6 is a critical cytokine that stimulates the growth of hematological and solid tumors and is synthesized by a wide range of cell types, including fibroblasts, ECs, epithelial cells, and monocytes as hematological tumor lines. Through the activation of JAK, it stimulates the transcription factors STAT. In NHL, lower progression-free survival and overall survival rates have been linked to higher blood IL-6 levels, and IL-6 production in HL cell lines has been demonstrated. Numerous investigations revealed that IL-6 expression correlated with early onset vascular development events, indicating that it may be involved in angiogenesis [2].&#x0D; Interleukin-6 (IL-6) is thought to play a crucial pathobiological function in classical HL among the biologic variables like cytokines. According to reports, adult patients with HL who have elevated serum interleukin-6 (IL-6) have better response rates, longer survival times, and B symptoms. TH-17 response may be elicited by HRS cells that express IL-6, but TH-2 response may be elicited by HRS cells that do not express IL-6. T-lymphocytes are known to be attracted by IL-6, and depending on how it interacts with other cytokines like TGF-beta, the lymphocytes may induce a TH-2 or TH-17 response. A significant cancer hallmark known as immune evasion can be brought on in cancer patients by the TH-2 response [3].

Spatial Tumor Microenvironment Characterization and Outcome of Relapsed/Refractory Classic Hodgkin Lymphoma

INTRODUCTION: Despite recent treatment advances, about half of relapsed or refractory classic Hodgkin lymphoma (r/r CHL) patients succumb to their disease after high dose chemotherapy followed by autologous stem cell transplantation (HDT/ASCT). Our group has previously developed a gene expression based prognostic assay (RHL30) that identifies high-risk r/r CHL patients treated with HDT/ASCT (J Clin Oncol 2017). However, RHL30 does not incorporate important information about cellular interactions, specific expression features of Hodgkin and Reed-Sternberg (HRS) cells and the spatial architecture of the tumor-microenvironment (TME). Here, we aimed to determine spatially resolved TME ecosystems and establish novel biomarkers associated with treatment failure in r/r CHL. METHODS: Using a customized marker panel specific for CHL biology, we performed imaging mass cytometry (IMC) using a tissue microarray containing formalin-fixed paraffin-embedded tissues from 169 CHL tumors, including 73 patients with paired primary and relapse samples, as well as 23 pretreatment diagnostic samples from patients in long-term remission. Segmentation was performed by the Ilastik machine learning package following the Bodenmiller IMC segmentation pipeline to obtain single cell level data. We used the Phenograph clustering algorithm to identify major cell types and functional subsets. For each cell, we calculated a spatial cell enrichment score, called 'spatial score', of a given cell type as the distance to the five nearest neighbor cells, capped at the spatial interaction range (50um). Patients were classified as having early relapse disease if their CHL progressed within 12 months after initial diagnosis. For prognostic model development, we used an empirical Bayesian approach based on LPS (linear prediction score). RESULTS: We obtained highly multiplexed images for a total of 7,146,042 cells that could be broadly clustered into T cell, macrophage, B cell as well as HRS cells using the phenograph tool. We also identified subsets within the HRS cell cluster, such as GATA3-high HRS cells and CXCR5-high HRS cells. We, then, investigated the difference of TME characteristics according to the disease status. Overall, CHL biopsies from early relapse demonstrated shared TME patterns between diagnostic and relapse samples, and were characterized by a lesser extent of CD8+ cells (P < 0.01) as well as enrichment of a myeloid cell population (P < 0.05). In contrast, late relapse samples often demonstrated significant TME changes between diagnostic and relapse biopsies (P < 0.01). Considering the previous finding of the superiority of relapse biopsies for outcome prediction in comparison to pretreatment diagnostic samples in r/r CHL, we again focused our prognostic model development on relapse biopsies. Using LASSO based analyses, four variables, CXCR5+ HRS cells (Hazard Ratio [HR]: 2.86), PD1+ CD4+ T cells (HR: 2.80), macrophage (HR: 1.99), and CXCR5+ B cells (HR: 0.19) were identified as factors that were significantly associated with post-ASCT failure free survival (FFS). Using these 4 variables, we developed a spatial score-based prognostic model (RHL-4S) and compared performance with a classical protein%-based model. The RHL-4S produced a high-risk group of patients with significantly inferior post-ASCT FFS compared with the low-risk group (5-year post-ASCT FFS: high risk, 38% vs low risk, 96%; P < 0.0001, Figure A) as well as inferior post-ASCT overall survival (OS) (5-year post-ASCT OS: high risk, 45% vs low risk, 95%; P < 0.0025). IMC analyses furthermore identified unique spatial architecture defined by CXCR5+ HRS cells. In particular, CXCR5+ HRS cells were spatially arranged together with other HRS cells forming cell clusters as an architectural feature (P < 0.05, Figure B). CXCR5+ HRS cells in these clusters were also characterized by a lower abundance of neighboring non-malignant immune cells, including CD4+ T cells and CD20+ B cells when compared to CXCR5- HRS cells. CONCLUSION We developed a novel prognostic model, RHL-4S, applicable to relapse biopsies of r/r CHL patients who were treated with ASCT. In particular, we have shown the interaction between CXCR5 on HRS cells with ligand-expressing CXCL13+ follicular T helper cells (Aoki et al, PNAS 2021) and macrophages as a prominent crosstalk axis in relapsed disease. This insight opens new avenues to predictive biomarker development. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

P043: Molecular pathogenesis of Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is one of the most frequent lymphomas in the Western world. Its malignant Hodgkin and Reed/Sternberg (HRS) cells are derived from pre-apoptotic germinal center B cells and only account for ca. 1% of the tumor cell mass. The surrounding inflammatory infiltrate is unable to establish an effective immune response against the HRS cells. To better understand HRS cell formation and their molecular pathogenesis, we aim to determine the mutational landscape of HRS cells. HRS cells of a total of 30 cases were isolated by microdissection or flow cytometry and subjected to exome or whole-genome sequencing. We confirmed recurrently mutated genes (e.g. SOCS1, TNFAIP3) but also found novel promising genes such as NLRC5, which is involved in MHCI expression and negative NFkB regulation. Intriguingly, mutational signatures associated with APOBEC and somatic hypermutation were identified. Moreover we are currently analyzing the WGS samples for mutations in gene regulatory regions, miRNA binding sites and gains and losses. Both WGS and WES show a wide variation in their mutational loads.

T028: Single-cell RNA sequencing reveals the interplay between circulating CD4 T cells, B cells and cancer-associated monocytes in classic Hodgkin lymphoma treated with PD-1 blockade

Classic Hodgkin lymphoma (cHL) is a largely MHC class I-negative tumor with recurrent 9p24.1/ PD-L1/ PD-L2 copy gains and the highest reported response rates to PD-1 blockade. In cHL, the efficacy of PD-1 blockade is closely associated with Hodgkin and Reed-Sternberg (HRS) cell expression of MHC class II, highlighting the potential role of CD4+ T-cell effectors and additional non-MHC class I-mediated mechanisms of tumor cell killing. We utilized scRNA sequencing to characterize the peripheral immune response to PD-1 blockade and more broadly define non-CD8+ dependent mechanisms of immune evasion in cHL. Peripheral blood mononuclear cells were obtained from 20 patients with relapsed/refractory (R/R) cHL treated with PD-1 blockade (nivolumab) on the CheckMate 205 clinical trial (cycle 1 day 1 [C1D1] and cycle 4 day 1 [C4D1]), 11 patients with newly diagnosed, previously untreated cHL and 13 healthy donors. Unlike healthy donors, all evaluated patients with cHL had circulating IFN stimulated adaptive and innate populations, including several distinct CD4+ T-cell effectors and an NK cell subset with reduced cytotoxic potential, and decreased numbers of B cells at all stages of differentiation. Patients with the most favorable responses to PD-1 blockade had: 1) significantly increased CD4+ T-cell receptor diversity and more abundant naïve/ central memory subsets; and 2) significantly higher B-cell receptor diversity and increased numbers of circulating B cells. The most abundant circulating CD3- population in patients with cHL was a newly identified monocyte subset with increased expression of multiple immunosuppressive and tumorigenic cytokines and chemokines, PD-L1 and SIRPa. This newly identified monocytic population was virtually absent from the blood of healthy donors. RNAscope analysis of the intact tumor microenvironment localized these tumor-infiltrating monocytes/macrophages to the immediate proximity of HRS cells. Monocytes from patients whose disease progressed following PD-1 blockade expressed significantly higher levels of immunosuppressive cytokine/chemokine signature which led to the development of a predictive transcriptional assay. We identified a comparable circulating monocyte population and transcriptional signature associated with unresponsiveness to PD-1 blockade in an additional solid tumor underscoring the broad-based significance of these findings.

Programmed death-ligand 1 (PD-L1) expression in Hodgkin’s lymphoma among Peruvian patients

Objective: Various studies on Hodgkin’s lymphoma (HL) have determined programmed death-ligand 1 (PD-L1) expression in Hodgkin and Reed-Sternberg (HRS) cells, with variable results. This protein has gained relevance for its role in theimmune response in malignant neoplasms. This work aimed to determine PD-L1 immunohistochemical expression in HRS cells and its relationship with age, sex, clinical stage and overall survival (OS) in a cohort of Peruvian patients. Materials and methods: Twenty-five (25) biopsies from patients diagnosed with HL were assessed, which allowed determining PD-L1 immunohistochemical expression in HRS cells in relation to OS and clinical data of the patients. Results: All cases showed PD-L1 expression in more than 1 % of tumor cells. There was no statistically significant difference in OS when two groups were compared in terms of PD-L1 expression with a cut-off point of 50 %, clinical stage (CS), age and sex. Conclusions: High PD-L1 expression was found in pre-treatment HL tumors. No association was found between PD-L1 expression, OS, age, sex or CS. Further studies with a larger number of patients are necessary to reassess the prognosticimpact of the expression of this protein in HL.

NFkB Pathway and Hodgkin Lymphoma.

The tumor cells that drive classical Hodgkin lymphoma (cHL), namely, Hodgkin and Reed-Sternberg (HRS) cells, display hallmark features that include their rareness in contrast with an extensive and rich reactive microenvironment, their loss of B-cell phenotype markers, their immune escape capacity, and the activation of several key biological pathways, including the constitutive activation of the NFkB pathway. Both canonical and alternative pathways are deregulated by genetic alterations of their components or regulators, EBV infection and interaction with the microenvironment through multiple receptors, including CD30, CD40, BAFF, RANK and BCMA. Therefore, NFkB target genes are involved in apoptosis, cell proliferation, JAK/STAT pathway activation, B-cell marker expression loss, cellular interaction and a positive NFkB feedback loop. Targeting this complex pathway directly (NIK inhibitors) or indirectly (PIM, BTK or NOTCH) remains a challenge with potential therapeutic relevance. Nodular predominant HL (NLPHL), a distinct and rare HL subtype, shows a strong NFkB activity signature because of mechanisms that differ from those observed in cHL, which is discussed in this review.