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.

Spatial and molecular profiling of the mononuclear phagocyte network in classic Hodgkin lymphoma.

Classic Hodgkin lymphoma (cHL) has a rich immune infiltrate, which is an intrinsic component of the neoplastic process. Malignant Hodgkin Reed-Sternberg cells (HRSCs) create an immunosuppressive microenvironment by the expression of regulatory molecules, preventing T-cell activation. It has also been demonstrated that mononuclear phagocytes (MNPs) in the vicinity of HRSCs express similar regulatory mechanisms in parallel, and their presence in tissue is associated with inferior patient outcomes. MNPs in cHL have hitherto been identified by a small number of canonical markers and are usually described as tumor-associated macrophages. The organization of MNP networks and interactions with HRSCs remains unexplored at high resolution. Here, we defined the global immune-cell composition of cHL and nonlymphoma lymph nodes, integrating data across single-cell RNA sequencing, spatial transcriptomics, and multiplexed immunofluorescence. We observed that MNPs comprise multiple subsets of monocytes, macrophages, and dendritic cells (DCs). Classical monocytes, macrophages and conventional DC2s were enriched in the vicinity of HRSCs, but plasmacytoid DCs and activated DCs were excluded. Unexpectedly, cDCs and monocytes expressed immunoregulatory checkpoints PD-L1, TIM-3, and the tryptophan-catabolizing protein IDO, at the same level as macrophages. Expression of these molecules increased with age. We also found that classical monocytes are important signaling hubs, potentially controlling the retention of cDC2 and ThExh via CCR1-, CCR4-, CCR5-, and CXCR3-dependent signaling. Enrichment of the cDC2-monocyte-macrophage network in diagnostic biopsies is associated with early treatment failure. These results reveal unanticipated complexity and spatial polarization within the MNP compartment, further demonstrating their potential roles in immune evasion by cHL.

Association between Epstein-Barr virus LMP-1 and Hodgkin lymphoma LMP-1 mechanisms in Hodgkin lymphoma development.

Hodgkin lymphoma is histologically characterised by the presence of Hodgkin (H) and Reed-Sternberg (RS) cells originating from germinal centre B-cells rearranged in the IgV gene. The formation of multinucleated RS cells is a product of telomere organisation in a process initiated by telomere aggregate accumulation in mononuclear H cells and may be mediated by latent membrane protein 1 (LMP-1) expression. LMP-1 is the main oncoprotein of EBV and supports several tumourigenic processes. LMP-1 may rescue proapoptotic B-cells through downregulation of B-cell receptor (BCR) components, mimicking and inducing multiple distinct B-cell signalling pathways to promote proliferation and survival, such as Janus kinase-signal transducer and activator of transcription (JAK-STAT), nuclear factor-kappa b (NF-кB), and cellular MYC (c-MYC), and inducing telomere instability mainly through Telomere repeat binding factor 2 (TRF2) downregulation to promote the formation of multinucleated RS cells. This review presents recent discoveries regarding the influence of LMP-1 on the surviving cellular signalling, genomic instability and mecanical formation of HRS cells.

Checkpoint inhibition enhances cell contacts between CD4+ T cells and Hodgkin-Reed-Sternberg cells of classic Hodgkin lymphoma.

Although checkpoint molecules like CTLA-4 and PD1 have been described several years ago, checkpoint inhibitors such as nivolumab (an anti-PD-1 antibody) have only recently been used to treat classic Hodgkin lymphoma (cHL). Several studies have shown convincing therapeutic effects of nivolumab in cHL. However, the mechanism of action of nivolumab in cHL is not fully understood. The aim of this study was to monitor changes in cell motility and cell contacts after administration of nivolumab to an in vitro model of cHL as well as to native hyperplastic lymphoid tissue and native human tissue from cHL. In both tissue and in vitro, CD4+, CD8+, CD30+ and CD20+ cell velocities were unchanged after nivolumab incubation. In contrast, in primary cHL tissue, the duration of cell contacts between CD4+ T cells and Hodgkin-Reed-Sternberg cells was significantly increased after 5 hours of nivolumab treatment, and the number of contacts with HRS cells was also slightly increased for CD4+ T cells (not significant), suggesting that CD4+ T cells in particular contribute to the cytotoxicity observed as a result of nivolumab therapy. There was no change in the duration of cell contacts in the hyperplastic lymphoid tissue after nivolumab incubation. In conclusion, we show here for the first time by imaging of native lymphoma tissue an enhanced interaction of CD4+ T cells and Hodgkin-Reed-Sternberg cells in cHL after nivolumab administration.

Steady-state approximations for Hodgkin-Huxley cell models: Reduction of order for uterine smooth muscle cell model.

Multi-scale mathematical bioelectrical models of organs such as the uterus, stomach or heart present challenges both for accuracy and computational tractability. These multi-scale models are typically founded on models of biological cells derived from the classic Hodkgin-Huxley (HH) formalism. Ion channel behaviour is tracked with dynamical variables representing activation or inactivation of currents that relax to steady-state dependencies on cellular membrane voltage. Timescales for relaxation may be orders of magnitude faster than companion ion channel variables or phenomena of physiological interest for the entire cell (such as bursting sequences of action potentials) or the entire organ (such as electromechanical coordination). Exploiting these time scales with steady-state approximations for relatively fast-acting systems is a well-known but often overlooked approach as evidenced by recent published models. We thus investigate feasibility of an extensive reduction of order for an HH-type cell model with steady-state approximations to the full dynamical activation and inactivation ion channel variables. Our effort utilises a published comprehensive uterine smooth muscle cell model that encompasses 19 ordinary differential equations and 105 formulations overall. The numerous ion channel submodels in the published model exhibit relaxation times ranging from order 10-1 to 105 milliseconds. Substitution of the faster dynamic variables with steady-state formulations demonstrates both an accurate reproduction of the full model and substantial improvements in time-to-solve, for test cases performed. Our demonstration here of an effective and relatively straightforward reduction method underlines the particular importance of considering time scales for model simplification before embarking on large-scale computations or parameter sweeps. As a preliminary complement to more intensive reduction of order methods such as parameter sensitivity and bifurcation analysis, this approach can rapidly and accurately improve computational tractability for challenging multi-scale organ modelling efforts.

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.

Interfollicular Classic Hodgkin Lymphoma: Report of a Case and a Brief Review of Literature.

Interfollicular Hodgkin lymphoma (IHL) has been rarely reported in the literature and is recognized by the WHO Classification as a morphologic pattern sometimes seen in mixed cellularity classic Hodgkin lymphoma (CHL). The changes may be subtle due to preservation of architecture. We report a case of a 9-year-old male with IHL showing preserved follicular architecture but with the presence of interfollicular infiltrates consisting of eosinophils, plasma cells, and Hodgkin-Reed-Sternberg (HRS) cells. Immunophenotyping confirmed the morphologic suspicion for IHL. A discussion and review of the literature are offered. We conclude that IHL is a variant that requires a high index of suspicion, as it may be easily missed due to the subtle morphologic features and preserved architecture seen in most cases. We further emphasize that unexplained interfollicular infiltrates of eosinophils may be clues that should prompt a search of HRS cells and consideration of immunohistochemical staining if needed.

Liquid biopsy: A promising tool for driving strategies and predicting failures in patients with classic Hodgkin lymphoma.

Classic Hodgkin lymphoma (cHL) consists of a heterogeneous group of haematological disorders that covers undifferentiated B cell neoplasms originating from germinal centre B cells. The HL molecular characterization still represents an ongoing challenge due to the low fraction of tumour Hodgkin and Reed-Sternberg cells mixed with a plethora of non-tumour haematological cells. In this scenario, next generation sequencing of liquid biopsy samples is emerging as a useful tool in HL patients' management. In this review, we aimed to overview the clinical and methodological topics regarding the implementation of molecular analysis in cHL, focusing on the role of liquid biopsy in diagnosis, follow-up, and response prediction.

Single-cell profiling reveals the importance of CXCL13/CXCR5 axis biology in lymphocyte-rich classic Hodgkin lymphoma.

Lymphocyte-rich classic Hodgkin lymphoma (LR-CHL) is a rare subtype of Hodgkin lymphoma. Recent technical advances have allowed for the characterization of specific cross-talk mechanisms between malignant Hodgkin Reed-Sternberg (HRS) cells and different normal immune cells in the tumor microenvironment (TME) of CHL. However, the TME of LR-CHL has not yet been characterized at single-cell resolution. Here, using single-cell RNA sequencing (scRNA-seq), we examined the immune cell profile of 8 cell suspension samples of LR-CHL in comparison to 20 samples of the mixed cellularity (MC, 9 cases) and nodular sclerosis (NS, 11 cases) subtypes of CHL, as well as 5 reactive lymph node controls. We also performed multicolor immunofluorescence (MC-IF) on tissue microarrays from the same patients and an independent validation cohort of 31 pretreatment LR-CHL samples. ScRNA-seq analysis identified a unique CD4+ helper T cell subset in LR-CHL characterized by high expression of Chemokine C-X-C motif ligand 13 (CXCL13) and PD-1. PD-1+CXCL13+ T cells were significantly enriched in LR-CHL compared to other CHL subtypes, and spatial analyses revealed that in 46% of the LR-CHL cases these cells formed rosettes surrounding HRS cells. MC-IF analysis revealed CXCR5+ normal B cells in close proximity to CXCL13+ T cells at significantly higher levels in LR-CHL. Moreover, the abundance of PD-1+CXCL13+ T cells in the TME was significantly associated with shorter progression-free survival in LR-CHL (P = 0.032). Taken together, our findings strongly suggest the pathogenic importance of the CXCL13/CXCR5 axis and PD-1+CXCL13+ T cells as a treatment target in LR-CHL.

[Clinicopathological features of primary mucosal CD30-positive T-cell lymphoproliferative disorders].

Objective: To investigate the clinicopathological features and differential diagnosis of primary mucosal CD30-positive T-cell lymphoproliferative disorders (pmCD30+TLPD). Methods: Eight cases of pmCD30+TLPD diagnosed from 2013 to 2023 at the Department of Pathology, Beijing Friendship Hospital Affiliated to Capital Medical University and Beijing Ludaopei Hospital were retrospectively collected. The immunophenotype, EBV infection status and T-cell receptor (TCR) clonability of tumor cells were examined. The clinicopathological features were analyzed and related literatures were reviewed. Results: There were 5 females and 3 males, aged 28 to 73 years, without B symptoms, lack of trauma and autoimmune diseases. Seven cases occurred in oral mucosa and one in anal canal mucosa. Submucosal nodules with ulcerations were presented in all cases except one, which only submucosal nodule. Morphologically, there was different distribution of allotypic lymphocytes in inflammatory background. Four cases showed "kidney-shaped", "embryonic" and "horseshoe-shaped" cells, and one case resembled Hodgkin and Reed/Sternberg (HRS) cells. Allotypic lymphocytes expressed CD3 (7/8), CD4+/CD8-(7/8) and CD4-/CD8-(1/8). CD30 was uniformly strongly positive while ALK and CD56 were negative. In situ hybridization of EBER was negative in five cases (5/5). Clonal TCR gene rearrangement was positive in two cases. Four patients did not receive radiotherapy or chemotherapy. All the seven patients survived without disease except one died due to concurrent leukopenia. Conclusions: pmCD30+TLPD had a broad morphological spectrum and could be easily confused with primary cutaneous CD30+TLPD and systemic ALK-negative anaplastic large cell lymphoma involving mucosa, which may lead to misdiagnosis. Although the majority of the cases had a favorable prognosis, a few cases relapsed or progressed to lymphoma.

CD30 induces Reed-Sternberg cell-like morphology and chromosomal instability in classic Hodgkin lymphoma cell lines.

Classic Hodgkin lymphoma (cHL) is characterized by multinucleated cells called Reed-Sternberg (RS) cells and genetic complexity. Although CD30 also characterizes cHL cells, its biological roles are not fully understood. In this report, we examined the link between CD30 and these characteristics of cHL cells. CD30 stimulation increased multinucleated cells resembling RS cells. We found chromatin bridges, a cause of mitotic errors, among the nuclei of multinucleated cells. CD30 stimulation induced DNA double-strand breaks (DSBs) and chromosomal imbalances. RNA sequencing showed significant changes in the gene expression by CD30 stimulation. We found that CD30 stimulation increased intracellular reactive oxygen species (ROS), which induced DSBs and multinucleated cells with chromatin bridges. The PI3K pathway was responsible for CD30-mediated generation of multinucleated cells by ROS. These results suggest that CD30 involves generation of RS cell-like multinucleated cells and chromosomal instability through induction of DSBs by ROS, which subsequently induces chromatin bridges and mitotic error. The results link CD30 not only to the morphological features of cHL cells, but also to the genetic complexity, both of which are characteristic of cHL cells.

The value of thymus and activation related chemokine immunohistochemistry in classic Hodgkin lymphoma diagnostics.

AIMS: Classic Hodgkin lymphoma (cHL) should be distinguished from its wide variety of histological mimics, including reactive conditions and mature B and T cell neoplasms. Thymus and activation-related chemokine (TARC) is produced in extremely high quantities by the Hodgkin/Reed-Sternberg (HRS) tumour cells and is largely responsible for the attraction of CD4+ T cells into the cHL tumour micro-environment. In the current study we evaluated the diagnostic potential of TARC immunohistochemistry in daily practice in a tertiary referral centre in the Netherlands. METHODS AND RESULTS: A total of 383 cases, approximately half of which were cHL mimics, were prospectively evaluated in the period from June 2014 to November 2020. In 190 cHL cases, 92% were TARC-positive and the majority of cases showed strong and highly specific staining in all HRS cells (77%). In most cases, TARC could discriminate between nodular lymphocyte-predominant and lymphocyte-rich Hodgkin lymphoma. HRS-like cells in mature lymphoid neoplasms were rarely positive (6.4%) and there was no TARC staining at all in 64 reactive lymphadenopathies. CONCLUSIONS: TARC immunohistochemistry has great value in differentiating between cHL and its mimics, including nodular lymphocyte-predominant Hodgkin lymphoma, reactive lymphadenopathies and mature lymphoid neoplasms with HRS-like cells.

Classic Hodgkin lymphoma in young people.

Classic Hodgkin lymphoma (CHL) is a unique form of lymphoid cancer featuring a heterogeneous tumor microenvironment and a relative paucity of malignant Hodgkin and Reed-Sternberg (HRS) cells with characteristic phenotype. Younger individuals (children, adolescents and young adults) are affected as often as the elderly, producing a peculiar bimodal age-incidence profile that has generated immense interest in this disease and its origins. Decades of epidemiological investigations have documented the populations most susceptible and identified multiple risk factors that can be broadly categorized as either biological or environmental in nature. Most risk factors result in overt immunodeficiency or confer more subtle alterations to baseline health, physiology or immune function. Epstein Barr virus, however, is both a risk factor and well-established driver of lymphomagenesis in a significant subset of cases. Epigenetic changes, along with the accumulation of somatic driver mutations and cytogenetic abnormalities are required for the malignant transformation of germinal center-experienced HRS cell precursors. Chromosomal instability and the influence of endogenous mutational processes are critical in this regard, by impacting genes involved in key signaling pathways that promote the survival and proliferation of HRS cells and their escape from immune destruction. Here we review the principal features, known risk factors and lymphomagenic mechanisms relevant to newly diagnosed CHL, with an emphasis on those most applicable to young people.

The characteristically weak PAX-5 staining of Reed-Sternberg cells surrounds distinct negatively stained block-like inclusions in classic Hodgkin Lymphoma.

No abstract available.

[Progressively transformed germinal center-like follicular T-cell lymphoma:a clinicopathological analysis of 14 cases].

Objective: To investigate the clinicopathologic features of progressively transformed germinal center-like follicular T-cell lymphoma (PTGC-like FTCL). Methods: The clinicopathologic data of 14 PTGC-like FTCL cases that were diagnosed at the Beijing Friendship Hospital Affiliated to the Capital Medical University from January 2017 to January 2022 were retrospectively collected. Clinicopathological features, immunophenotype, and Epstein-Barr virus (EBV) infection status were analyzed in these cases. Polymerase chain reaction (PCR) was performed to detect the clonal gene rearrangements of T cell receptor (TCR) and the immunoglobulin (Ig) in 10 and 8 cases, respectively. Results: The male to female ratio was 5∶2. The median age was 61 years (range 32-70 years). All patients had lymphadenopathy at the time of diagnosis. By using the Ann Arbor system staging, seven cases were classified as stage Ⅰ-Ⅱ, and seven cases as stage Ⅲ-Ⅳ. Seven cases had B symptoms, four cases had splenomegaly, and two cases had skin rash and pruritus. Previously, three cases were diagnosed as classic Hodgkin's lymphoma, three cases as small B-cell lymphoma, two cases as atypical lymphoid hyperplasia unable to exclude angioimmunoblastic T-cell lymphoma (AITL), one case as EBV-associated lymphoproliferative disorder, and one case as peripheral T-cell lymphoma (PTCL) associated with the proliferation of B cells. All the 14 cases showed that the large nodules were composed of mature CD20+, IgD+B lymphocytes admixed with small aggregates of neoplastic cells with pale to clear cytoplasm. Moreover, hyperplastic germinal centers (GCs) and Hodgkin/Reed-Sternberg-like (HRS-like) cells were seen within these nodules in two and five cases, respectively. The neoplastic cells expressed CD3 (14/14), CD4 (14/14), PD1 (14/14), ICOS (14/14), CD10 (9/14), bcl-6 (12/14), CXCL13 (10/14), and CD30 (10/14). The HRS-like cells in five cases expressed CD20 (2/5), PAX5 (5/5), CD30 (5/5), CD15 (2/5), LCA (0/5), OCT2 (5/5) and BOB1 (2/5). Moreover, neoplastic T cells formed rosettes around HRS-like cells. EBV-encoded RNA (EBER) in situ hybridization showed scattered, small, positive bystander B lymphocytes in 8/14 cases, including 3/5 cases containing HRS-like cells. All tested cases (including five with HRS-like cells) showed monoclonal TCR gene rearrangement and polyclonal Ig gene rearrangement. Conclusions: PTGC-like FTCL is a rare tumor originated from T-follicular helper cells. It could be distinguished from angioimmunoblastic T-cell lymphoma by the formation of follicular structure, and lack of follicular dendritic cell proliferation outside the follicles and the polymorphous inflammatory background. In addition, it should be differentiated from lymphocyte-rich classical Hodgkin's lymphoma and low-grade B cell lymphoma.

Checkpoint CD47 expression in classical Hodgkin lymphoma.

The glycoprotein CD47 regulates antiphagocytic activity via signal regulatory protein alpha (SIRPa). This study investigated CD47 expression on Hodgkin and Reed-Sternberg (HRS) cells in the classical Hodgkin lymphoma (cHL) tumour microenvironment and its correlation with prognosis, programmed-death (PD) immune markers, and SIRPa+ leukocytes. We conducted immunohistochemistry with CD47 and SIRPa antibodies on diagnostic biopsies (tissue microarrays) from cHL patients from two cohorts (n = 178). In cohort I (n = 136) patients with high expression of CD47 on HRS cells (n = 48) had a significantly inferior event-free survival [hazard ratio (HR) = 5.57; 95% confidence interval (CI), 2.78-11.20; p < 0.001] and overall survival (OS) (HR = 8.54; 95% CI, 3.19-22.90; p < 0.001) compared with patients with low expression (n = 88). The survival results remained statistically significant in multivariable Cox regression adjusted for known prognostic factors. In cohort II (n = 42) high HRS cell CD47 expression also carried shorter event-free survival (EFS) (HR = 5.96; 95% CI, 1.20-29.59; p = 0.029) and OS (HR = 5.61; 95% CI, 0.58-54.15; p = 0.136), although it did not retain statistical significance in the multivariable analysis. Further, high CD47 expression did not correlate with SIRPa+ leukocytes or PD-1, PD-L1 and PD-L2 expression. This study provides a deeper understanding of the role of CD47 in cHL during an era of emerging CD47 therapies.

Epstein-Barr virus infection patterns in nodular lymphocyte-predominant Hodgkin lymphoma.

AIMS: To investigate Epstein-Barr virus (EBV) latency types in 19 cases of EBV-positive nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), as such information is currently incomplete. METHODS AND RESULTS: Immunohistochemistry (IHC) for CD20, CD79a, PAX5, OCT2, CD30, CD15, CD3 and programmed cell death protein 1 was performed. For EBV detection, in-situ hybridisation (ISH) for EBV-encoded RNA (EBER) was employed combined with IHC for EBV-encoded latent membrane protein (LMP)-1, EBV-encoded nuclear antigen (EBNA)-2, and EBV-encoded BZLF1. In 95% of the cases, neoplastic cells with features of Hodgkin and Reed-Sternberg (HRS) cells were present, mostly showing expression of CD30. In all cases, the B-cell phenotype was largely intact, and delineation from classic Hodgkin lymphoma (CHL) was further supported by myocyte enhancer factor 2B (MEF2B) detection. All tumour cells were EBER-positive except in two cases. EBV latency type II was most frequent (89%) and type I was rare. Cases with latency type I were CD30-negative. Five cases contained some BZLF1-positive and/or EBNA-2-positive bystander lymphocytes. CONCLUSIONS: As HRS morphology of neoplastic cells and CD30 expression are frequent features of EBV-positive NLPHL, preservation of the B-cell transcription programme, MEF2B expression combined with NLPHL-typical architecture and background composition facilitate distinction from CHL. EBER ISH is the method of choice to identify these cases. The majority present with EBV latency type II, and only rare cases present with latency type I, which can be associated with missing CD30 expression. The presence of occasional bystander lymphocytes expressing BZLF1 and/or EBNA-2 and the partial EBV infection of neoplastic cells in some cases could indicate that EBV is either not primarily involved or is only a transient driver in the pathogenesis of EBV-positive NLPHL.

Colonic infiltration of chronic lymphocytic leukemia with Hodgkin Reed Sternberg-like cells.

A 72-year-old man was diagnosed with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and signet ring cell carcinoma in a gastric biopsy. He underwent a subtotal gastrectomy + lymphadenectomy + chemotherapy + radiotherapy. He did not receive treatment for the lymphoma. Eight years after the diagnosis, he presented with alternating diarrhea and constipation. Physical examination revealed bilateral laterocervical, axillary, and inguinal lymphadenopathies. The laboratory results showed LDH: 286 UI/l and Beta-2-microglobulin: 6.4 mg/L. CT scan showed a mass that seems to involve the cecum and terminal ileum with multiple locoregional, retroperitoneal, and mesenteric lymphadenopathies. He underwent a right hemicolectomy. Macroscopically, we identified an ulcerated mass of approximately 7 x 6 x 5 cm. in the cecum. The microscopic findings were consistent with chronic lymphocytic leukemia (CD20+ and CD5+) with scattered Hodgkin reed Sternberg-like cells CD30 and EBER+ (Epstein-Barr virus-encoded RNA) by in situ hybridization (ISH) positive (Fig. 1). The patient received treatment with mini-CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone) plus rituximab with partial response after the third cycle.

[Epigenetic modification as a therapeutic approach for B-cell lymphoma].

Genes that regulate immunological activities are transiently suppressed by epigenetic modification during the germinal center reaction of B cells and reactivated when B cells exit the germinal center. Mutations of EZH2 and other epigenetic modifier genes are frequently involved in the pathogenesis of follicular lymphoma and lead to silencing of the genes necessary for exiting the germinal center. Tazemetostat, an EZH2 inhibitor, has been approved for the treatment of follicular lymphoma with EZH2 gain-of-function mutations in Japan. Tazemetostat restores the expressions of MHC and CD58 in lymphoma cells and synergistically enhances the immune reactions of T and natural killer cells against lymphoma cells. Tazemetostat also induces lymphoma cells to secrete CCL17/TARC and enhances T-cell migration. CD58 and CCL17 are known to play central roles in the formation of T-cell-rich tumor microenvironment of Hodgkin lymphoma. We found that tazemetostat enhances the expression of genes overexpressed in Hodgkin/Reed-Sternberg cells. Epigenetic modifiers and new molecular targeted therapies are expected to provide new insights into the pathogenesis of lymphoma and mechanisms determining the histology of lymphoma.

[Treatment strategy for pediatric Hodgkin lymphoma].

Pediatric Hodgkin lymphoma (HL) is a malignant disease that arises from lymphoid reticulum cells, which can metastasize to the spleen, liver, and bone marrow, including the lymph nodes. Classic HL is characterized by the presence of CD30-positive Hodgkin Reed-Sternberg (HRS) cell proliferation. Its symptoms include fever, night sweats, weight loss, itching, splenomegaly, and hepatomegaly, along with painless lymphadenopathy. Although HL has long achieved a high cure rate, late complications such as cardiac complications, infertility, and secondary cancers still pose a threat. The current treatment standard includes a combination of multiagent chemotherapy and low-dose radiation therapy, and attempts have been made to establish a regimen that omits radiation therapy in patients who respond well to initial therapy. The introduction of new molecular-targeted agents is expected to result in further treatment reduction.