Origin and pathogenesis of nodular lymphocyte-predominant Hodgkin lymphoma as revealed by global gene expression analysis

Potential role of the P2X7 receptor in the proliferation of human diffused large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of invasive non-Hodgkin lymphoma. 60-70% of patients are curable with current chemoimmunotherapy, whereas the rest are refractory or relapsed. Understanding of the interaction between DLBCL cells and tumor microenvironment raises the hope of improving overall survival of DLBCL patients. P2X7, a member of purinergic receptors P2X family, is activated by extracellular ATP and subsequently promotes the progression of various malignancies. However, its role in DLBCL has not been elucidated. In this study, the expression level of P2RX7 in DLBCL patients and cell lines was analyzed. MTS assay and EdU incorporation assay were carried out to study the effect of activated/inhibited P2X7 signaling on the proliferation of DLBCL cells. Bulk RNAseq was performed to explore potential mechanism. The results demonstrated high level expression of P2RX7 in DLBCL patients, typically in patients with relapse DLBCL. 2'(3')-O-(4-benzoylbenzoyl) adenosine 5-triphosphate (Bz-ATP), an agonist of P2X7, significantly accelerated the proliferation of DLBCL cells, whereas delayed proliferation was detected when administrated with antagonist A740003. Furthermore, a urea cycle enzyme named CPS1 (carbamoyl phosphate synthase 1), which up-regulated in P2X7-activated DLBCL cells while down-regulated in P2X7-inhibited group, was demonstrated to involve in such process. Our study reveals the role of P2X7 in the proliferation of DLBCL cells and implies that P2X7 may serve as a potential molecular target for the treatment of DLBCL.

Spatial phenotyping of nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma with sparse tumor B-cells and a favorable prognosis. Variant growth patterns of NLPHL, however, often show advanced stage, progression to T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) and a worse prognosis. We studied the tumor microenvironment (TME) of NLPHL and THRLBCL using highplex imaging and spatial profiling at the single cell level. Our findings show distinct differences in TME composition and spatial configuration that differ among typical and variant NLPHL and THRLBCL. Typical NLPHL show abundant helper T-cell subsets, while THRLBCL show abundant cytotoxic T-cells and macrophages. Tumor B-cell size and content is lowest in typical NLPHL, followed by variant NLPHL, and highest in THRLBCL, whereas an opposite trend characterized TME B-cells. CD4/CD8 double-positive T-cells are seen in all NLPHL but not in the majority of THRLBCL and are spatially distant from LP-cells and TFH-rosettes. The differences in macrophage/monocyte content in distinguishing NLPHL pattern E from THRLBCL is further corroborated in independent cohorts of cases. Our results validate the current approach to classification and in addition provide novel insights that could be leveraged to refine clinical management for patients with this spectrum of lymphomas.

The biology of classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is distinguished by several important biological characteristics. The presence of Hodgkin Reed Sternberg (HRS) cells is a defining feature of this disease. The tumor microenvironment with relatively few HRS cells in an expansive infiltrate of immune cells is another key feature. Numerous cell-cell mediated interactions and a plethora of cytokines in the tumor microenvironment collectively work to promote HRS cell growth and survival. Aberrancy and constitutive activation of core signal transduction pathways are a hallmark trait of cHL. Genetic lesions contribute to these dysregulated pathways and evasion of the immune system through a variety of mechanisms is another notable feature of cHL. While substantial elucidation of the biology of cHL has enabled advancements in therapy, increased understanding in the future of additional mechanisms driving cHL may lead to new treatment opportunities.

An anti-CD19/CTLA-4 switch improves efficacy and selectivity of CAR T cells targeting CD80/86-upregulated DLBCL

Chimeric antigen receptor T cell (CAR T) therapy is a potent treatment for relapsed/refractory (r/r) B cell lymphomas but provides lasting remissions in only ∼40% of patients and is associated with serious adverse events. We identify an upregulation of CD80 and/or CD86 in tumor tissue of (r/r) diffuse large B cell lymphoma (DLBCL) patients treated with tisagenlecleucel. This finding leads to the development of the CAR/CCR (chimeric checkpoint receptor) design, which consists of a CD19-specific first-generation CAR co-expressed with a recombinant CTLA-4-linked receptor with a 4-1BB co-stimulatory domain. CAR/CCR T cells demonstrate superior efficacy in xenograft mouse models compared with CAR T cells, superior long-term activity, and superior selectivity in in vitro assays with non-malignant CD19+ cells. In addition, immunocompetent mice show an intact CD80-CD19+ B cell population after CAR/CCR T cell treatment. The results reveal the CAR/CCR design as a promising strategy for further translational study.

Inhibition of choline metabolism in an angioimmunoblastic T-cell lymphoma preclinical model reveals a new metabolic vulnerability as possible target for treatment

BACKGROUND

Angioimmunoblastic T-cell lymphoma (AITL) is a malignancy with very poor survival outcome, in urgent need of more specific therapeutic strategies. The drivers of malignancy in this disease are CD4+ follicular helper T cells (Tfh). The metabolism of these malignant Tfh cells was not yet elucidated. Therefore, we decided to identify their metabolic requirements with the objective to propose a novel therapeutic option.

METHODS

To reveal the prominent metabolic pathways used by the AITL lymphoma cells, we relied on metabolomic and proteomic analysis of murine AITL (mAITL) T cells isolated from our established mAITL model. We confirmed these results using AITL patient and healthy T cell expression data.

RESULTS

Strikingly, the mAITL Tfh cells were highly dependent on the second branch of the Kennedy pathway, the choline lipid pathway, responsible for the production of the major membrane constituent phosphatidylcholine. Moreover, gene expression data from Tfh cells isolated from AITL patient tumors, confirmed the upregulation of the choline lipid pathway. Several enzymes involved in this pathway such as choline kinase, catalyzing the first step in the phosphatidylcholine pathway, are upregulated in multiple tumors other than AITL. Here we showed that treatment of our mAITL preclinical mouse model with a fatty acid oxydation inhibitor, significantly increased their survival and even reverted the exhausted CD8 T cells in the tumor into potent cytotoxic anti-tumor cells. Specific inhibition of Chokα confirmed the importance of the phosphatidylcholine production pathway in neoplastic CD4 + T cells, nearly eradicating mAITL Tfh cells from the tumors. Finally, the same inhibitor induced in human AITL lymphoma biopsies cell death of the majority of the hAITL PD-1high neoplastic cells.

CONCLUSION

Our results suggest that interfering with choline metabolism in AITL reveals a specific metabolic vulnerability and might represent a new therapeutic strategy for these patients.

[IgD expression in various immunoarchitectural patterns of nodular lymphocyte predominant Hodgkin lymphoma in children]

BACKGROUND

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) consist of lymphocyte predominant cell or LP-cell. Despite their origin from active germinal centers, in some cases LP-cells express IgD, which is characteristic of naive B-lymphocytes of the mantle zone. Due to the rarity of NLPHL, assessing the frequency of IgD-positive cases is difficult. This marker can serve not only for differential diagnosis with other diseases, but also indicate the possible heterogeneity of NLPHL, which is currently represented by six immunoarchitectural patterns.

OBJECTIVE

To determine the frequency of IgD-positive cases of NLPHL in children with subsequent assessment of the association with types of immunoarchitectural patterns.

MATERIAL AND METHODS

The study included 52 cases of NLPHL, which were divided to typical and atypical patterns. Differences between two groups were compared using Fisher's exact tests.

RESULTS

IgD expression was found in LP-cells in 26 of 52 cases (50%) and was positively correlated with atypical types (typical - 5/23, 21.7% vs atypical - 21/29, 72.4%, p=0.0003), among which pattern C was most common.

CONCLUSION

Due to the high incidence of IgD-positive cases in NLPHL, this marker may be useful in differential diagnosis with histologic mimics. At the same time, positive IgD status was associated with atypical patterns, which may likely determine the different biology of neoplastic cells within the same form.

B-cell receptor reactivity against Rothia mucilaginosa in nodular lymphocyte-predominant Hodgkin lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a Hodgkin lymphoma expressing functional B-cell receptors (BCR). Recently, we described a dual stimulation model of IgD+ lymphocyte-predominant cells by Moraxella catarrhalis antigen RpoC and its superantigen MID/hag, associated with extralong CDR3 and HLA-DRB1*04 or HLADRB1* 07 haplotype. The aim of the present study was to extend the antigen screening to further bacteria and viruses. The fragment antibody-binding (Fab) regions of seven new and 15 previously reported cases were analyzed. The reactivity of non-Moraxella spp.-reactive Fab regions against lysates of Rothia mucilaginosa was observed in 5/22 (22.7%) cases. Galactofuranosyl transferase (Gltf) and 2,3-butanediol dehydrogenase (Bdh) of R. mucilaginosa were identified by comparative silver- and immuno-staining in two-dimensional gels, with subsequent mass spectrometry and validation by western blots and enzyme-linked immunosorbent assay. Both R. mucilaginosa Gltf and Bdh induced BCR pathway activation and proliferation in vitro. Apoptosis was induced by recombinant Gltf/ETA'-immunotoxin conjugates in DEV cells expressing recombinant R. mucilaginosa-reactive BCR. Reactivity against M. catarrhalis RpoC was confirmed in 3/7 newly expressed BCR (total 10/22 reactive to Moraxella spp.), resulting in 15/22 (68.2%) cases with BCR reactivity against defined bacterial antigens. These findings strengthen the hypothesis of bacterial trigger contributing to subsets of NLPHL.

The pathobiology of select adolescent young adult lymphomas

Lymphoid cancers are among the most frequent cancers diagnosed in adolescents and young adults (AYA), ranging from approximately 30%-35% of cancer diagnoses in adolescent patients (age 10-19) to approximately 10% in patients aged 30-39 years. Moreover, the specific distribution of lymphoid cancer types varies by age with substantial shifts in the subtype distributions between pediatric, AYA, adult, and older adult patients. Currently, biology studies specific to AYA lymphomas are rare and therefore insight into age-related pathogenesis is incomplete. This review focuses on the paradigmatic epidemiology and pathogenesis of select lymphomas, occurring in the AYA patient population. With the example of posttransplant lymphoproliferative disorders, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma (incl. pediatric-type follicular lymphoma), and mediastinal lymphomas (incl. classic Hodgkin lymphoma, primary mediastinal large B cell lymphoma and mediastinal gray zone lymphoma), we here illustrate the current state-of-the-art in lymphoma classification, recent molecular insights including genomics, and translational opportunities. To improve outcome and quality of life, international collaboration in consortia dedicated to AYA lymphoma is needed to overcome challenges related to siloed biospecimens and data collections as well as to develop studies designed specifically for this unique population.

Microenvironmental immune cell alterations across the spectrum of nodular lymphocyte predominant Hodgkin lymphoma and T-cell/histiocyte-rich large B-cell lymphoma

Background

The clinicopathological spectrum of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), also known as nodular lymphocyte predominant B-cell lymphoma, partially overlaps with T-cell/histiocyte-rich large B-cell lymphoma (THRLCBL). NLPHL histology may vary in architecture and B-cell/T-cell composition of the tumour microenvironment. However, the immune cell phenotypes accompanying different histological patterns remain poorly characterised.

Methods

We applied a multiplexed immunofluorescence workflow to identify differential expansion/depletion of multiple microenvironmental immune cell phenotypes between cases of NLPHL showing different histological patterns (as described by Fan et al, 2003) and cases of THRLBCL.

Results

FOXP3-expressing T-regulatory cells were conspicuously depleted across all NLPHL cases. As histology progressed to variant Fan patterns C and E of NLPHL and to THRLBCL, there were progressive expansions of cytotoxic granzyme-B-expressing natural killer and CD8-positive T-cells, PD1-expressing CD8-positive T-cells, and CD163-positive macrophages including a PDL1-expressing subset. These occurred in parallel to depletion of NKG2A-expressing natural killer and CD8-positive T-cells.

Discussion

These findings provide new insights on the immunoregulatory mechanisms involved in NLPHL and THLRBCL pathogenesis, and are supportive of an increasingly proposed biological continuum between these two lymphomas. Additionally, the findings may help establish new biomarkers of high-risk disease, which could support a novel therapeutic program of immune checkpoint interruption targeting the PD1:PDL1 and/or NKG2A:HLA-E axes in the management of high-risk NLPHL and THRLBCL.

A Review of the Flow Cytometric Findings in Classic Hodgkin Lymphoma, Nodular Lymphocyte Predominant Hodgkin Lymphoma and T Cell/Histiocyte-Rich Large B Cell Lymphoma

Classic Hodgkin lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and T cell/histiocyte-rich large B cell lymphoma form a unique set of lymphomas with similar morphologic growth patterns (occasional neoplastic cells within a prominent cellular cell background) that are pathobiologically related. Distinguishing these entities has been historically difficult by flow cytometry; however, our laboratory has developed antibody-fluorochrome combinations capable of immunophenotyping these lymphomas. Additionally, characterization of the background reactive lymphocytes can aid in narrowing the differential diagnosis. This review summarizes the immunophenotypic features and insights of the neoplastic and reactive populations found in this unique group of lymphomas.

Emerging Insights into Liver X Receptor α in the Tumorigenesis and Therapeutics of Human Cancers

Liver X receptor α (LXRα), a member of the nuclear receptor superfamily, is identified as a protein activated by ligands that interacts with the promoters of specific genes. It regulates cholesterol, bile acid, and lipid metabolism in normal physiological processes, and it participates in the development of some related diseases. However, many studies have demonstrated that LXRα is also involved in regulating numerous human malignancies. Aberrant LXRα expression is emerging as a fundamental and pivotal factor in cancer cell proliferation, invasion, apoptosis, and metastasis. Herein, we outline the expression levels of LXRα between tumor tissues and normal tissues via the Oncomine and Tumor Immune Estimation Resource (TIMER) 2.0 databases; summarize emerging insights into the roles of LXRα in the development, progression, and treatment of different human cancers and their diversified mechanisms; and highlight that LXRα can be a biomarker and therapeutic target in diverse cancers.

Establishment of the lymphoid ETS-code reveals deregulated ETS genes in Hodgkin lymphoma

The human family of ETS transcription factors numbers 28 genes which control multiple aspects of development, notably the differentiation of blood and immune cells. Otherwise, aberrant expression of ETS genes is reportedly involved in forming leukemia and lymphoma. Here, we comprehensively mapped ETS gene activities in early hematopoiesis, lymphopoiesis and all mature types of lymphocytes using public datasets. We have termed the generated gene expression pattern lymphoid ETS-code. This code enabled identification of deregulated ETS genes in patients with lymphoid malignancies, revealing 12 aberrantly expressed members in Hodgkin lymphoma (HL). For one of these, ETS gene ETV3, expression in stem and progenitor cells in addition to that in developing and mature T-cells was mapped together with downregulation in B-cell differentiation. In contrast, subsets of HL patients aberrantly overexpressed ETV3, indicating oncogenic activity in this B-cell malignancy. Analysis of ETV3-overexpressing HL cell line SUP-HD1 demonstrated genomic duplication of the ETV3 locus at 1q23, GATA3 as mutual activator, and suppressed BMP-signalling as mutual downstream effect. Additional examination of the neighboring ETS genes ETS1 and FLI1 revealed physiological activities in B-cell development and aberrant downregulation in HL patient subsets. SUP-HD1 showed genomic loss on chromosome 11, del(11)(q22q25), targeting both ETS1 and FLI1, underlying their downregulation. Furthermore, in the same cell line we identified PBX1-mediated overexpression of RIOK2 which inhibited ETS1 and activated JAK2 expression. Collectively, we codified normal ETS gene activities in lymphopoiesis and identified oncogenic ETS members in HL.

An integrative bioinformatics investigation and experimental validation of chromobox family in diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is one of the most aggressive malignant tumors. Chromobox (CBX) family plays the role of oncogenes in various malignancies.

METHODS

The transcriptional and protein levels of CBX family were confirmed by GEPIA, Oncomine, CCLE, and HPA database. Screening of co-expressed genes and gene function enrichment analysis were performed by GeneMANIA and DAVID 6.8. The prognostic value, immune cell infiltration and drug sensitivity analysis of CBX family in DLBCL were performed by Genomicscape, TIMER2.0, and GSCALite database. Confirmatory Tests of CBX family protein expression in DLBCL were performed by immunohistochemistry.

RESULTS

The mRNA and protein expressions of CBX1/2/3/5/6 were higher in DLBCL tissues than control groups. Enrichment analysis showed that the functions of CBX family were mainly related to chromatin remodeling, methylation-dependent protein binding, and VEGF signaling pathway. The high mRNA expressions of CBX2/3/5/6 were identified to be associated with short overall survival (OS) in DLBCL patients. Multivariate COX regression indicated that CBX3 was independent prognostic marker. Immune infiltration analysis revealed that the mRNA expressions of CBX family (especially CBX1, CBX5, and CBX6) in DLBCL were significantly correlated with the infiltration of most immune cells (including B cells, CD8 + T cells, CD4 + T cells, neutrophils, monocytes, macrophages, and Treg cells). Meanwhile, there was a strong correlation between the expression levels of CBX1/5/6 and surface markers of immune cells, such as the widely studied PVR-like protein receptor/ligand and PDL-1 immune checkpoint. Notably, our study found that DLBCL cells with CBX1 over-expression were resistant to the common anti-tumor drugs, but CBX2/5 had two polarities. Finally, we confirmed the higher expressions of CBX1/2/3/5/6 in DLBCL tissues compared with control groups by immunohistochemistry.

CONCLUSION

We provided a detailed analysis of the relationship between the CBX family and the prognosis of DLBCL. Distinguished from other studies, We found that high mRNA expressions of CBX2/3/5/6 were associated with poor prognosis in DLBCL patients, and Multivariate COX regression indicated that CBX3 was independent prognostic marker. Besides, our study also found an association between the CBX family and anti-tumour drug resistance, and provided a relationship between CBX family expression and immune cell infiltration.

The Polyamine-Hypusine Circuit Controls an Oncogenic Translational Program Essential for Malignant Conversion in MYC-Driven Lymphoma

The MYC oncoprotein is activated in a broad spectrum of human malignancies and transcriptionally reprograms the genome to drive cancer cell growth. Given this, it is unclear if targeting a single effector of MYC will have therapeutic benefit. MYC activates the polyamine-hypusine circuit, which posttranslationally modifies the eukaryotic translation factor eIF5A. The roles of this circuit in cancer are unclear. Here we report essential intrinsic roles for hypusinated eIF5A in the development and maintenance of MYC-driven lymphoma, where the loss of eIF5A hypusination abolishes malignant transformation of MYC-overexpressing B cells. Mechanistically, integrating RNA sequencing, ribosome sequencing, and proteomic analyses revealed that efficient translation of select targets is dependent upon eIF5A hypusination, including regulators of G1-S phase cell-cycle progression and DNA replication. This circuit thus controls MYC's proliferative response, and it is also activated across multiple malignancies. These findings suggest the hypusine circuit as a therapeutic target for several human tumor types.

SIGNIFICANCE

Elevated EIF5A and the polyamine-hypusine circuit are manifest in many malignancies, including MYC-driven tumors, and eIF5A hypusination is necessary for MYC proliferative signaling. Not-ably, this circuit controls an oncogenic translational program essential for the development and maintenance of MYC-driven lymphoma, supporting this axis as a target for cancer prevention and treatment. See related commentary by Wilson and Klein, p. 248. This article is highlighted in the In This Issue feature, p. 247.

Nodular lymphocyte-predominant Hodgkin lymphoma: current management strategies and evolving approaches to individualize treatment

INTRODUCTION

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma entity accounting for roughly 5% of all Hodgkin lymphoma (HL) cases. In contrast to classical HL, the malignant cells in NLPHL are positive for CD20 but lack CD30. The disease usually has an indolent clinical course resulting in high long-term survival rates.

AREAS COVERED

In this review, treatment options for NLPHL are summarized and factors that may help to individualize treatment are discussed.

EXPERT OPINION

Stage IA NLPHL without clinical risk factors should be treated with limited-field radiotherapy alone. In all other stages, NLPHL patients have excellent outcomes after standard HL approaches. The question of whether the addition of an anti-CD20 antibody to standard HL chemotherapy protocols or the use of approaches typically applied in B-cell non-Hodgkin lymphoma improve treatment results is unanswered until now. Different management strategies ranging from low-intensity treatment to high-dose chemotherapy and autologous stem cell transplantation have demonstrated activity in relapsed NLPHL. Second-line treatment is thus chosen individually. The major aim of NLPHL research is to spare toxicity and reduce the risk for treatment-related adverse events in low-risk patients while treating higher-risk patients with appropriate intensity. To this end, novel tools to guide treatment are required.

Unlocking the Mysteries of Alpha-N-Terminal Methylation and its Diverse Regulatory Functions

Protein post-translation modifications (PTMs) are a critical regulatory mechanism of protein function. Protein α-N-terminal (Nα) methylation is a conserved PTM across prokaryotes and eukaryotes. Studies of the Nα methyltransferases responsible for Να methylation and their substrate proteins have shown that the PTM involves diverse biological processes, including protein synthesis and degradation, cell division, DNA damage response, and transcription regulation. This review provides an overview of the progress toward the regulatory function of Να methyltransferases and their substrate landscape. More than 200 proteins in humans and 45 in yeast are potential substrates for protein Nα methylation based on the canonical recognition motif, XP[KR]. Based on recent evidence for a less stringent motif requirement, the number of substrates might be increased, but further validation is needed to solidify this concept. A comparison of the motif in substrate orthologs in selected eukaryotic species indicates intriguing gain and loss of the motif across the evolutionary landscape. We discuss the state of knowledge in the field that has provided insights into the regulation of protein Να methyltransferases and their role in cellular physiology and disease. We also outline the current research tools that are key to understanding Να methylation. Finally, challenges are identified and discussed that would aid in unlocking a system-level view of the roles of Να methylation in diverse cellular pathways.

CCL17 acts as an antitumor chemokine in micromilieu‐driven immune skewing

BACKGROUND

Chemokines are critical players in the local immune responses to tumors. CCL17 (thymus and activation-regulated chemokine, TARC) and CCL22 (macrophage-derived chemokine, MDC) can attract CCR4-bearing cells involving the immune landscape of cancer. However, their direct roles and functional states in tumors remain largely unclear.

METHODS

We analyzed the lymphoma-related scRNA-seq and bulk RNA-seq datasets and identified the CCL17/CCL22-CCR4 axis as the unique participant of the tumor microenvironment. Then we edited the A20 lymphoma cell line to express CCL17 and CCL22 and assessed their function using three mouse models (Balb/C mouse, Nude mouse, and NSG mouse). In addition, we retrospectively checked the relationship between the CCL17/CCL22-CCR4 axis and the survival rates of cancer patients.

RESULTS

The active CCL17/CCL22-CCR4 axis is a distinctive feature of the Hodgkin lymphoma microenvironment. CCR4 is widely expressed in immune cells but highly exists on the surface of NK, NKT, and Treg cells. The tumor model of Balb/C mice showed that CCL17 acts as an anti-tumor chemokine mediated by activated T cell response. In addition, the tumor model of Nude mice showed that CCL17 recruits NK cells for inhibiting lymphoma growth and enhances the NK-cDC1 interaction for resisting IL4i1-mediated immunosuppression. Interestingly, CCL17-mediated antitumor immune responses depend on lymphoid lineages but not mainly myeloid ones. Furthermore, we found CCL17/CCL22-CCR4 axis cannot be regarded as biomarkers of poor prognosis in most cancer types from the TCGA database.

CONCLUSION

We provided direct evidence of antitumor functions of CCL17 mediated by the recruitment of conventional T cells, NKT cells, and NK cells. Clinical survival outcomes of target gene (CCL17, CCL22, and CCR4) expression also identified that CCL17/CCL22-CCR4 axis is not a marker of poor prognosis.

Progression of Hodgkin lymphoma and plasma cell neoplasms: Report from the 2021 SH/EAHP Workshop

OBJECTIVES

To summarize cases submitted to the 2021 Society for Hematopathology/European Association for Haematopathology Workshop under the categories of progression of Hodgkin lymphoma, plasmablastic myeloma, and plasma cell myeloma.

METHODS

The workshop panel reviewed 20 cases covered in this session. In addition, whole-exome sequencing (WES) and whole-genome RNA expression analysis were performed on 10 submitted cases, including 6 Hodgkin lymphoma and 4 plasma neoplasm cases.

RESULTS

The cases of Hodgkin lymphoma included transformed cases to or from various types of B-cell lymphoma with 1 exception, which had T-cell differentiation. The cases of plasma cell neoplasms included cases with plasmablastic progression, progression to plasma cell leukemia, and secondary B-lymphoblastic leukemia. Gene variants identified by WES included some known to be recurrent in Hodgkin lymphoma and plasma cell neoplasm. All submitted Hodgkin lymphoma samples showed 1 or more of these mutations: SOCS1, FGFR2, KMT2D, RIT1, SPEN, STAT6, TET2, TNFAIP3, and ZNF217.

CONCLUSIONS

Better molecular characterization of both of these neoplasms and mechanisms of progression will help us to better understand mechanisms of progression and perhaps develop better prognostic models, as well as identifying novel therapeutic targets.

Treatment approaches for nodular lymphocyte-predominant Hodgkin lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare variant of Hodgkin lymphoma characterized by a persistent risk of relapse but an excellent overall survival. Historically, it was treated similarly to classic Hodgkin lymphoma, but efforts have been made to deintensify treatment due to risk of late toxicity associated with intensive therapy. For patients with completely resected stage IA NLPHL, no further treatment may be considered, particularly for pediatric patients. For those with stage I-II NLPHL without risk factors such as B symptoms, sites>2, or variant pattern histology, lower intensity treatment with radiotherapy or chemotherapy alone may be sufficient. However, combined modality therapy is a standard treatment for favorable and unfavorable risk stage I-II NLPHL associated with excellent progression-free and overall survival rates. For patients with advanced stage NLPHL, the optimal chemotherapy is not defined, but R-CHOP appears to be an effective treatment. Efforts to study NLPHL through multicenter collaborative efforts are crucial to develop evidence based and individualized treatments for patients with NLPHL.

Inhibition of USP1 reverses the chemotherapy resistance through destabilization of MAX in the relapsed/refractory B-cell lymphoma

The patients with relapsed and refractory diffuse large B-cell lymphoma (DLBCL) have poor prognosis, and a novel and effective therapeutic strategy for these patients is urgently needed. Although ubiquitin-specific protease 1 (USP1) plays a key role in cancer, the carcinogenic effect of USP1 in B-cell lymphoma remains elusive. Here we found that USP1 is highly expressed in DLBCL patients, and high expression of USP1 predicts poor prognosis. Knocking down USP1 or a specific inhibitor of USP1, pimozide, induced cell growth inhibition, cell cycle arrest and autophagy in DLBCL cells. Targeting USP1 by shRNA or pimozide significantly reduced tumor burden of a mouse model established with engraftment of rituximab/chemotherapy resistant DLBCL cells. Pimozide significantly retarded the growth of lymphoma in a DLBCL patient-derived xenograft (PDX) model. USP1 directly interacted with MAX, a MYC binding protein, and maintained the stability of MAX through deubiquitination, which promoted the transcription of MYC target genes. Moreover, pimozide showed a synergetic effect with etoposide, a chemotherapy drug, in cell and mouse models of rituximab/chemotherapy resistant DLBCL. Our study highlights the critical role of USP1 in the rituximab/chemotherapy resistance of DLBCL through deubiquitylating MAX, and provides a novel therapeutic strategy for rituximab/chemotherapy resistant DLBCL.

The utility of IMP3 immunohistochemical staining in differentiating nodular lymphocyte predominant Hodgkin Lymphoma from T-Cell/Histiocyte-Rich large B-Cell lymphoma

INTRODUCTION

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and T cell/histiocyte-rich large B-cell lymphoma (THRLBCL) have overlapping histological features that make their diagnosis challenging. Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is a recently proposed diagnostic marker for Hodgkin's lymphoma. The aim of this study was to determine the ability of IMP3 in differentiating NLPHL from THRLBCL.

METHODS

In this retrospective study, the formalin-fixed paraffin-embedded blocks from 56 patients (28 NLPHL and 28 large B cell lymphoma (LBCL, including 16 THRLBCL and 12 DLBCL, NOS) cases based on immunohistochemistry (IHC) were included. Sample sections were stained for IMP3 using IHC method. Moderate to strong staining in at least 10% of tumor cells was considered positive IMP3 expression.

RESULTS

The mean age of the patients was 41.25 ± 16.08 years old. The majority of the patients were male. There was a significant age difference between NLPHL (34.61 ± 16.44 years old) and LBCL (47.89 ± 12.85 years) groups (p = 0.001). No significant difference was seen in gender and site between NLPHL and LBCL groups. The expression of IMP3 was mainly strong in LBCL group, while it was heterogeneously distributed among NLPHL samples ranging from weak to strong (p < 0.001). It was determined that strong IMP3 expression at 55.00% can differentiate LBCL from NLPHL with 71.4% sensitivity and 71.4% specificity.

CONCLUSION

Our findings showed that IMP3 may be a good complement in differentiating NLPHL cases from THRLBCL.

Bioinformatics Analysis of miRNAs Targeting TRAF5 in DLBCL Involving in NF-κB Signaling Pathway and Affecting the Apoptosis and Signal Transduction

Background

Diffuse large B-cell lymphoma (DLBCL) is an aggressive B-cell lymphoma with high heterogeneity. There is an unmet need to investigate valid indicators for the diagnosis and therapy of DLBCL.

Methods

GEO database was utilized to screen for differentially expressed genes (DEGs) and differential miRNAs in DLBCL tissues. The Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were applied to analyse DEGs. Then multiple databases were searched for related miRNAs within DLBCL, TNF receptor-associated factor 5 (TRAF5) and NF-kappa B (NF-κB) signaling pathways. The KOBAS database was used to assist in the screening of miRNAs of interest and construct the regulatory network of miRNA-mRNA. Finally, the expression level and diagnostic performance of miRNAs were analyzed with GEO datasets, and DEGs were identified from the GEPIA database.

Results

DEGs were significantly concentrated in the NF-κB signaling pathway and cytokine-cytokine receptor interaction, and involved in the process of immune response and protein binding. MiR-15a-5p, miR-147a, miR-192-5p, miR-197-3p, miR-532-5p, and miR-650 were revealed to be targeting TRAF5 and participating in NF-κB signaling pathway and might impact the apoptosis and signal transduction of DLBCL. In the GEPIA database, TRAF5 was significantly overexpressed in DLBCL. The expression of miR-197-3p was upregulated within GEO datasets, while the rest of the miRNAs were downregulated in DLBCL.

Conclusions

Subsets of miRNAs may participate in the NF-κB signaling pathway by co-targeting TRAF5 and could be prospective biomarkers exploring the pathogenesis of DLBCL.

Expression and Significance of Cyclin-Dependent Protein Kinase 6 in Diffuse Large B-Cell Lymphoma

Objective

To study the relationship between cyclin-dependent protein kinase 6 (CDK6) expression in diffuse large B-cell lymphoma (DLBCL) and the clinical biological behavior and prognosis.

Methods

Data mining was performed using the Oncomine and The Cancer Genome Atlas (TCGA) databases to analyze the expression level of CDK6 in DLBCL. CDK6 alterations in DLBCL and related functional networks were analyzed with c-BioPortal and the Gene Set Enrichment Analysis was performed by using DAVID and FunRich software. In addition, screening for differential gene expression of CDK6 was done and enriched by using LinkedOmics. Finally, formalin-fixed and paraffin-embedded (FFPE) tissue samples from 102 patients with DLBCL were collected from the Department of Pathology, Shanxi Cancer Hospital (Taiyuan, Shanxi, China) from January 2015 through December 2020. All cases had complete clinical course records. Thirty cases of lymph node reactive hyperplasia tissues were used as controls. The expression of CDK6 in DLBCL tissues was detected by qRT‑PCR and immunohistochemistry.

Results

Bioinformatics analysis: The data showed that mRNA expression level and DNA copy number variations (CNVs) of CDK6 were significantly higher in DLBCL as compared to normal tissue (P ˂ 0.05). Based on C-BioPortal analysis, we speculated that amplification was the most common copy of CDK6 CNV in DLBCL. Through Gene Ontology (GO) analysis of these genes, it was found that the proteins were mainly located in the nucleus and cytoplasm. The biological interaction network of CDK6 alterations were found to participate primarily in the G1-S phase of the process. Analysis of LinkedOmics mRNA sequencing data showed that three genes were positively correlated with CDK6 expression: PSMD1, C2orf29 and ASB1. Through experimental verification, we found that CDK6 was overexpressed in DLBCL, and the expression of CDK6 mRNA and protein in DLBCL were positively correlated with Ann Arbor staging and IPI score (P<0.05), and negatively correlated with overall survival (P<0.001).

Conclusion

Data mining results and experiments revealed and confirmed multi-level evidence for the importance of CDK6 in DLBCL; hence, CDK6 may be a potential marker in DLBCL. Thus, our study will perhaps lay the foundation for further research on the role of CDK6 in the genesis and development of DLBCL.

Downregulation of STAT3 in Epstein-Barr Virus-Positive Hodgkin Lymphoma

STAT3 is a transcription factor which is activated via various signaling transduction pathways or Epstein-Barr virus (EBV) infection and plays an oncogenic role in lymphoid malignancies including Hodgkin lymphoma (HL). The tumor cells of HL are derived from germinal center B-cells and transformed by chromosomal rearrangements, aberrant signal transduction, deregulation of developmental transcription factors, and EBV activity. HL cell lines represent useful models to investigate molecular principles and deduced treatment options of this malignancy. Using cell line L-540, we have recently shown that constitutively activated STAT3 drives aberrant expression of hematopoietic NKL homeobox gene HLX. Here, we analyzed HL cell line AM-HLH which is EBV-positive but, nevertheless, HLX-negative. Consistently, AM-HLH expressed decreased levels of STAT3 proteins which were additionally inactivated and located in the cytoplasm. Combined genomic and expression profiling data revealed several amplified and overexpressed gene candidates involved in opposed regulation of STAT3 and EBV. Corresponding knockdown studies demonstrated that IRF4 and NFATC2 inhibited STAT3 expression. MIR155 (activated by STAT3) and SPIB (repressed by HLX) showed reduced and elevated expression levels in AM-HLH, respectively. However, treatment with IL6 or IL27 activated STAT3, elevated expression of HLX and MIR155, and inhibited IRF4. Taken together, this cell line deals with two conflicting oncogenic drivers, namely, JAK2-STAT3 signaling and EBV infection, but is sensitive to switch after cytokine stimulation. Thus, AM-HLH represents a unique cell line model to study the pathogenic roles of STAT3 and EBV and their therapeutic implications in HL.

Integrated analysis of the clinical consequence and associated gene expression of ALK in ALK-positive human cancers

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor that is genetically altered in several cancers, including NSCLC, melanoma, lymphoma, and other tumors. Although ALK is associated with various cancers, the relationship between ALK expression and patient prognosis in different cancers is poorly understood. Here, using multidimensional approaches, we revealed the correlation between ALK expression and the clinical outcomes of patients with LUAD, melanoma, OV, DLBC, AML, and BC. We analyzed ALK transcriptional expression, patient survival rate, genetic alteration, protein network, and gene and microRNA (miRNA) co-expression. Compared to that in normal tissues, higher ALK expression was found in LUAD, melanoma, and OV, which are associated with poor patient survival rates. In contrast, lower transcriptional expression was found to decrease the survival rate of patients with DLBC, AML, and BC. A total of 202 missense mutations, 17 truncating mutations, 7 fusions, and 3 in-frame mutations were identified. Further, 17 genes and 19 miRNAs were found to be exclusively co-expressed and echinoderm microtubule-associated protein-like 4 (EML4) was identified as the most positively correlated gene (log odds ratio >3). The gene ontology and signaling pathways of the genes co-expressed with ALK in these six cancers were also identified. Our findings offer a basis for ALK as a prognostic biomarker and therapeutic target in cancers, which will potentially contribute to precision oncology and assist clinicians in identifying suitable treatment options.

Hodgkin Lymphoma: Biology and Differential Diagnostic Problem

Hodgkin lymphomas (HLs) are lymphoid neoplasms that are morphologically defined as being composed of dysplastic cells, namely, Hodgkin and Reed–Sternberg cells, in a reactive inflammatory background. The biological nature of HLs has long been unclear; however, our understanding of HL-related genetics and tumor microenvironment interactions is rapidly expanding. For example, cell surface overexpression of programmed cell death 1 ligand 1 (CD274/PD-L1) is now considered a defining feature of an HL subset, and targeting such immune checkpoint molecules is a promising therapeutic option. Still, HLs comprise multiple disease subtypes, and some HL features may overlap with its morphological mimics, posing challenging diagnostic and therapeutic problems. In this review, we summarize the recent advances in understanding the biology of HLs, and discuss approaches to differentiating HL and its mimics.

Germinal Center-Related G Protein-Coupled Receptors in Antibody-Mediated Autoimmune Skin Diseases: from Basic Research to Clinical Trials

Germinal center (GC) reaction greatly contributes to the humoral immune response, which begins in lymph nodes or other secondary lymphoid organs after follicular B cells are activated by T-dependent antigens. The GCs then serve as a platform for follicular B cells to complete clonal expansion and somatic hypermutation and then interact with follicular dendritic cells (FDC) and follicular helper T cells (Tfh). Through the interaction between the immune cells, significant processes of the humoral immune response are accomplished, such as antibody affinity maturation, class switching, and production of memory B cells and plasma cells. Cell positioning during the GC reaction is mainly mediated by the chemokine receptors and lipid receptors, which both belong to G protein-coupled receptors (GPCRs) family. There are some orphan GPCRs whose endogenous ligands are unclear yet contribute to the regulation of GC reaction as well. This review will give an introduction on the ligands and functions of two types of GC-relating GPCRs-chemokine receptors like CXCR4 and CXCR5, as well as emerging de-orphanized GPCRs like GPR183, GPR174, and P2RY8. The roles these GPCRs play in several antibody-mediated autoimmune skin diseases will be also discussed, including systemic lupus erythematosus (SLE), pemphigus, scleroderma, and dermatomyositis. Besides, GPCRs are excellent drug targets due to the unique structure and vital functions. Therefore, this review is aimed at providing readers with a focused knowledge about the role that GPCRs play in GC reaction, as well as in provoking the development of GPCR-targeting agents for immune-mediated diseases besides autoimmune diseases.

An Update on the Pathology and Molecular Features of Hodgkin Lymphoma

Simple Summary

Hodgkin lymphomas (HLs) include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular findings in HLs have contributed to dramatic changes in the treatment and identification of tumor characteristics. For example, PD-1/PD-L1 blockade and brentuximab vedotin, an anti-CD30 antibody bearing a cytotoxic compound, are now widely used in patients with CHL. Biological continuity between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma has been highlighted. An era of novel therapeutics for HL has begun. The aim of this paper is to review the morphologic, immunophenotypic, and molecular features of CHL and NLPHL, which must be understood for the development of novel therapeutics.

Abstract

Hodgkin lymphomas (HLs) are lymphoid neoplasms derived from B cells and consist histologically of large neoplastic cells known as Hodgkin and Reed–Sternberg cells and abundant reactive bystander cells. HLs include two main types, classic HL (CHL) and nodular lymphocyte predominant HL (NLPHL). Recent molecular analyses have revealed that an immune evasion mechanism, particularly the PD-1/PD-L1 pathway, plays a key role in the development of CHL. Other highlighted key pathways in CHL are NF-κB and JAK/STAT. These advances have dramatically changed the treatment for CHL, particularly relapsed/refractory CHL. For example, PD-1 inhibitors are now widely used in relapsed/refractory CHL. Compared with CHL, NLPHL is more characterized by preserved B cell features. Overlapping morphological and molecular features between NLPHL and T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) have been reported, and biological continuity between these two entities has been highlighted. Some THRLBCLs are considered to represent progression from NLPHLs. With considerable new understanding becoming available from molecular studies in HLs, therapies and classification of HLs are continually evolving. This paper offers a summary of and update on the pathological and molecular features of HLs for a better understanding of the diseases.

Nodular Lymphocyte-predominant Hodgkin Lymphoma With Nodular Sclerosis: An Underrecognized Feature Associated With Pattern D

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) with unusual features, including some that can overlap morphologically with classic Hodgkin lymphoma (CHL), have been described. Herein, we describe 12 cases of NLPHL with fibrous bands and capsular fibrosis resembling, in part, nodular sclerosis (NS) CHL. Seven of 12 cases harbored Reed-Sternberg-like cells, further suggestive of CHL, but all cases lacked associated eosinophils and/or plasma cells in the background. In this cohort, all cases had areas of so-called pattern D (nodular T-cell rich) as a sole component in 7 (58%) cases or as a hybrid pattern along with pattern E (diffuse T-cell/histiocyte-rich) in 5 (42%) cases. The immunophenotype of the large neoplastic cells in these cases supported their being lymphocyte predominant cells of NLPHL, positive for CD20, CD79a, and OCT2, and negative for CD15 and CD30. However, PAX5 was weak in 9 of 11 cases similar to Hodgkin/Reed-Sternberg cells in CHL. We conclude that some cases of NLPHL are associated with fibrous bands and capsular fibrosis and resemble, in part, NS CHL. In our experience, NLPHL with NS-like features occurs in 10% to 15% of cases of NLPHL and is associated with a variant pattern (D and/or E). In addition, all patients in this cohort were not treated before biopsy, suggesting that the prominent sclerosis in these cases is inherent to disease biology. Recognition of NLPHL with NS-like features further expands the morphologic spectrum of NLPHL and helps avoid potential misdiagnosis as CHL.

Comprehensive Landscape of STEAP Family Members Expression in Human Cancers: Unraveling the Potential Usefulness in Clinical Practice Using Integrated Bioinformatics Analysis

The human Six-Transmembrane Epithelial Antigen of the Prostate (STEAP) family comprises STEAP1-4. Several studies have pointed out STEAP proteins as putative biomarkers, as well as therapeutic targets in several types of human cancers, particularly in prostate cancer. However, the relationships and significance of the expression pattern of STEAP1-4 in cancer cases are barely known. Herein, the Oncomine database and cBioPortal platform were selected to predict the differential expression levels of STEAP members and clinical prognosis. The most common expression pattern observed was the combination of the over- and underexpression of distinct STEAP genes, but cervical and gastric cancer and lymphoma showed overexpression of all STEAP genes. It was also found that STEAP genes’ expression levels were already deregulated in benign lesions. Regarding the prognostic value, it was found that STEAP1 (prostate), STEAP2 (brain and central nervous system), STEAP3 (kidney, leukemia and testicular) and STEAP4 (bladder, cervical, gastric) overexpression correlate with lower patient survival rate. However, in prostate cancer, overexpression of the STEAP4 gene was correlated with a higher survival rate. Overall, this study first showed that the expression levels of STEAP genes are highly variable in human cancers, which may be related to different patients’ outcomes.

Comprehensive analysis of the expression and significance of CXCLs in human diffuse large B-cell lymphoma

CXCL chemokines (CXCLs) are small cytokines or signal proteins secreted by cells that have been proven to be linked to the occurrence and development of many kinds of cancer. However, the expression and diagnostic and prognostic value of CXCLs in diffuse large B-cell lymphoma (DLBCL) remain to be further studied. We obtained CXCL transcription and survival data of patients with DLBCL from Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), The Cancer Genome Atlas (TCGA), TIMER and cBioPortal databases. R software, STRING and EXCEL were used to process the data. This study discovered that the expression levels of CXCL9-14 in DLBCL were higher than those in normal tissues, while CXCL4, CXCL7 and CXCL8 were lower in tumor than in normal tissues. The expression levels of CXCL2, CXCL10 and CXCL11 were related to tumor stage. CXCL9-14 could be used as an auxiliary molecular marker for the diagnosis of DLBCL. CXCL17 might be a potential prognostic marker of DLBCL.

A comparison and review of the flow cytometric findings in classic Hodgkin lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, T cell/histiocyte rich large B cell lymphoma, and primary mediastinal large B cell lymphoma

The "Hodgkin-like" lymphomas including classic Hodgkin lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, T cell/histiocyte rich large B cell lymphoma, and primary mediastinal large B cell lymphoma have been shown to be pathobiologically related. With the exception of primary mediastinal large B cell lymphoma, these lymphomas have similar morphologic growth patterns with occasional neoplastic cells within a prominent reactive cell background. Historically, distinguishing these entities was difficult by flow cytometry; however, over the past 15 years, our laboratory has developed antibody-fluorochrome combinations capable of accurately distinguishing these entities by their immunoprofile. Additionally, an algorithmic approach based on characterization of the background reactive B-cell and T-cell populations can aid in narrowing the differential diagnosis. This review summarizes both the morphologic and immunophenotypic features and the current flow cytometric insights of the neoplastic and reactive populations found in this unique subset of lymphomas.

Establishment of the TBX-code reveals aberrantly activated T-box gene TBX3 in Hodgkin lymphoma

T-box genes encode transcription factors which control basic processes in development of several tissues including cell differentiation in the hematopoietic system. Here, we analyzed the physiological activities of all 17 human T-box genes in early hematopoiesis and in lymphopoiesis including developing and mature B-cells, T-cells, natural killer (NK)-cells and innate lymphoid cells. The resultant expression pattern comprised six genes, namely EOMES, MGA, TBX1, TBX10, TBX19 and TBX21. We termed this gene signature TBX-code which enables discrimination of normal and aberrant activities of T-box genes in lymphoid malignancies. Accordingly, expression analysis of T-box genes in Hodgkin lymphoma (HL) patients using a public profiling dataset revealed overexpression of EOMES, TBX1, TBX2, TBX3, TBX10, TBX19, TBX21 and TBXT while MGA showed aberrant downregulation. Analysis of T-cell acute lymphoid leukemia patients indicated aberrant overexpression of six T-box genes while no deregulated T-box genes were detected in anaplastic large cell lymphoma patients. As a paradigm we focused on TBX3 which was ectopically activated in about 6% of HL patients analyzed. Normally, TBX3 is expressed in tissues like lung, adrenal gland and retina but not in hematopoiesis. HL cell line KM-H2 expressed enhanced TBX3 levels and was used as an in vitro model to identify upstream regulators and downstream targets in this malignancy. Genomic studies of this cell line showed focal amplification of the TBX3 locus at 12q24 which may underlie its aberrant expression. In addition, promoter analysis and comparative expression profiling of HL cell lines followed by knockdown experiments revealed overexpressed transcription factors E2F4 and FOXC1 and chromatin modulator KDM2B as functional activators. Furthermore, we identified repressed target genes of TBX3 in HL including CDKN2A, NFKBIB and CD19, indicating its respective oncogenic function in proliferation, NFkB-signaling and B-cell differentiation. Taken together, we have revealed a lymphoid TBX-code and used it to identify an aberrant network around deregulated T-box gene TBX3 in HL which promotes hallmark aberrations of this disease. These findings provide a framework for future studies to evaluate deregulated T-box genes in lymphoid malignancies.

CCR7 in Blood Cancers - Review of Its Pathophysiological Roles and the Potential as a Therapeutic Target

According to the classical paradigm, CCR7 is a homing chemokine receptor that grants normal lymphocytes access to secondary lymphoid tissues such as lymph nodes or spleen. As such, in most lymphoproliferative disorders, CCR7 expression correlates with nodal or spleen involvement. Nonetheless, recent evidence suggests that CCR7 is more than a facilitator of lymphatic spread of tumor cells. Here, we review published data to catalogue CCR7 expression across blood cancers and appraise which classical and novel roles are attributed to this receptor in the pathogenesis of specific hematologic neoplasms. We outline why novel therapeutic strategies targeting CCR7 might provide clinical benefits to patients with CCR7-positive hematopoietic tumors.

Integrated bioinformatics analysis reveals dynamic candidate genes and signaling pathways involved in the progression and prognosis of diffuse large B-cell lymphoma

Background

Diffuse large B-cell lymphoma (DLBCL) is a highly heterogeneous malignancy with varied outcomes. However, the fundamental mechanisms remain to be fully defined.

Aim

We aimed to identify core differentially co-expressed hub genes and perturbed pathways relevant to the pathogenesis and prognosis of DLBCL.

Methods

We retrieved the raw gene expression profile and clinical information of GSE12453 from the Gene Expression Omnibus (GEO) database. We used integrated bioinformatics analysis to identify differentially co-expressed genes. The CIBERSORT analysis was also applied to predict tumor-infiltrating immune cells (TIICs) in the GSE12453 dataset. We performed survival and ssGSEA (single-sample Gene Set Enrichment Analysis) (for TIICs) analyses and validated the hub genes using GEPIA2 and an independent GSE31312 dataset.

Results

We identified 46 differentially co-expressed hub genes in the GSE12453 dataset. Gene expression levels and survival analysis found 15 differentially co-expressed core hub genes. The core genes prognostic values and expression levels were further validated in the GEPIA2 database and GSE31312 dataset to be reliable (p < 0.01). The core genes’ main KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichments were Ribosome and Coronavirus disease-COVID-19. High expressions of the 15 core hub genes had prognostic value in DLBCL. The core genes showed significant predictive accuracy in distinguishing DLBCL cases from non-tumor controls, with the area under the curve (AUC) ranging from 0.992 to 1.00. Finally, CIBERSORT analysis on GSE12453 revealed immune cells, including activated memory CD4⁺ T cells and M0, M1, and M2-macrophages as the infiltrates in the DLBCL microenvironment.

Conclusion

Our study found differentially co-expressed core hub genes and relevant pathways involved in ribosome and COVID-19 disease that may be potential targets for prognosis and novel therapeutic intervention in DLBCL.

Flow Cytometric Detection of the Double-Positive (CD4+CD8+)/PD-1bright T-Cell Subset Is Useful in Diagnosing Nodular Lymphocyte-Predominant Hodgkin Lymphoma

CONTEXT.—

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is characterized by neoplastic lymphocyte-predominant cells frequently rimmed by CD3+/CD57+/programmed death receptor-1 (PD-1)+ T cells. Because of the rarity of lymphocyte-predominant cells in most cases, flow cytometric studies on NLPHL often fail to show evidence of malignancy.

OBJECTIVE.—

To evaluate the diagnostic utility of PD-1 in detecting NLPHL by flow cytometry, in conjunction with the CD4:CD8 ratio and the percentage of T cells doubly positive for CD4 and CD8.

DESIGN.—

Flow cytometric data obtained from cases of NLPHL (n = 10), classical Hodgkin lymphoma (n = 20), B-cell non-Hodgkin lymphoma (n = 22), T-cell non-Hodgkin lymphoma (n = 5), benign lymphoid lesions (n = 20), angioimmunoblastic T-cell lymphomas (n = 6) and T-cell/histiocyte-rich large B-cell lymphomas (n = 2) were analyzed and compared.

RESULTS.—

Compared with the other groups, NLPHL showed significantly higher values in the following parameters: CD4:CD8 ratio, percentage of T cells doubly positive for CD4 and CD8, percentage of PD-1-positive T cells, and median fluorescence intensity of PD-1 expression in the doubly positive for CD4 and CD8 subset. Using a scoring system (0-4) based on arbitrary cutoffs for these 4 parameters, all 10 NLPHL cases scored 3 or higher, as compared with only 3 cases from the other groups, producing an overall sensitivity of 100% and a specificity of 96% (72 of 75). Two of the 3 outliers were non-Hodgkin lymphoma, and both showed definitive immunophenotypic abnormalities leading to the correct diagnosis. The remaining outlier was a case of T-cell/histiocyte-rich large B-cell lymphoma.

CONCLUSIONS.—

The inclusion of anti-PD-1 in flow cytometry is useful for detecting NLPHL in fresh tissue samples, most of which would have otherwise been labeled as nondiagnostic or reactive lymphoid processes.

CD20-Negative Nodular Lymphocyte-Predominant Hodgkin Lymphoma: A 20-Year Consecutive Case Series From a Tertiary Cancer Center

CONTEXT.—

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare, indolent Hodgkin lymphoma subtype with distinct clinicopathologic features and treatment paradigms. The neoplastic lymphocyte-predominant cells typically express bright CD20 and other B-cell antigens, which distinguishes them from Hodgkin/Reed-Sternberg cells of lymphocyte-rich classic Hodgkin lymphoma.

OBJECTIVE.—

To characterize the clinicopathologic features of CD20-negative NLPHL at a single institution.

DESIGN.—

A retrospective search for CD20-negative NLPHL in our pathology archives and medical records was conducted.

RESULTS.—

Of 486 NLPHL patients identified with CD20 available for review, 14 (2.8%) had LP cells with absent CD20 expression. Patients with prior rituximab administration (n = 7) and insufficient clinical history (n = 1) were excluded, leaving 6 patients with rituximab-naïve, CD20-negative NLPHL. A broad immunohistochemical panel showed the LP cells in all cases expressed B-cell antigens, particularly Oct-2, although PAX5 and CD79a were frequently also dim. CD30, CD15, and Epstein-Barr virus-encoded small RNAs were negative in all evaluated cases. Two patients had high-risk variant immunoarchitectural pattern D. One patient had extranodal disease, involving the spleen and bone, and was suspected to have large cell transformation. Standard NLPHL therapy was given, including local radiation and/or chemotherapy. Of 5 patients with available follow-up, 4 are alive in complete remission after therapy, and 1 is alive with relapsed disease.

CONCLUSIONS.—

NLPHL can lack CD20 de novo without prior rituximab therapy. In such cases, extensive immunophenotyping helps distinguish NLPHL from lymphocyte-rich classic Hodgkin lymphoma, which differ in clinical behavior and therapy. In our series, CD20-negative NLPHL showed both classic and variant histologic patterns and the expected range of clinical behavior seen in NLPHL, including 1 case with suspected large cell transformation.

Diagnostic and prognostic value of secreted protein acidic and rich in cysteine in the diffuse large B-cell lymphoma

BACKGROUND

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix-associated protein. Studies have revealed that SPARC is involved in the cell interaction and function including proliferation, differentiation, and apoptosis. However, the role of SPARC in cancer is controversial, as it was reported as the promoter or suppressor in different cancers. Further, the role of SPARC in lymphoma is unclear.

AIM

To identify the expression and significance of SPARC in lymphoma, especially in diffuse large B-cell lymphoma (DLBCL).

METHODS

The expression analysis of SPARC in different cancers was evaluated with Oncomine. The Brune, Eckerle, Piccaluga, Basso, Compagno, Alizadeh, and Rosenwald datasets were included to evaluate the mRNA expression of SPARC in lymphoma. The Cancer Genome Atlas (TCGA)-DLBCL was used to analyze the diagnostic value of SPARC in DLBCL. The Compagno and Brune DLBCL datasets were used for validation. Then, the diagnostic value was evaluated with the receiver operating characteristic (ROC) curve. The Kaplan-Meier plot was conducted with TCGA-DLBCL, and the ROC analysis was performed based on the survival time. Further, the overall survival analysis based on the level of SPARC expression was performed with the GSE4475 and E-TABM-346. The Gene Set Enrichment Analyses (GSEA) was performed to make the underlying mechanism-regulatory networks.

RESULTS

The pan-cancer analysis of SPARC showed that SPARC was highly expressed in the brain and central nervous system, breast, colon, esophagus, stomach, head and neck, pancreas, and sarcoma, especially in lymphoma. The overexpression of SPARC in lymphoma, especially DLBCL, was confirmed in several datasets. The ROC analysis revealed that SPARC was a valuable diagnostic biomarker. More importantly, compared with DLBCL patients with low SPARC expression, those with higher SPARC expression represented a higher overall survival rate. The ROC analysis showed that SPARC was a favorable prognostic biomarker for DLBCL. Results of the GSEA confirmed that the high expression of SPARC was closely associated with focal adhesion, extracellular matrix receptor interaction, and leukocyte transendothelial migration, which suggested that SPARC may be involved in the regulation of epithelial-mesenchymal transition, KRAS, and myogenesis in DLBCL.

CONCLUSION

SPARC was highly expressed in DLBCL, and the overexpression of SPARC showed sound diagnostic value. More interestingly, the overexpression of SPARC might be a favorable prognostic biomarker for DLBCL, suggesting that SPARC might be an inducible factor in the development of DLBCL, and inducible SPARC was negative in some oncogenic pathways. All the evidence suggested that inducible SPARC might be a good diagnostic and prognostic biomarker for DLBCL.

NPM1 Is a Prognostic Biomarker Involved in Immune Infiltration of Lung Adenocarcinoma and Associated With m6A Modification and Glycolysis

Background

Overexpression of NPM1 can promote the growth and proliferation of various tumor cells. However, there are few studies on the comprehensive analysis of NPM1 in lung adenocarcinoma (LUAD).

Methods

TCGA and GEO data sets were used to analyze the expression of NPM1 in LUAD and clinicopathological analysis. The GO/KEGG enrichment analysis of NPM1 co-expression and gene set enrichment analysis (GSEA) were performed using R software package. The relationship between NPM1 expression and LUAD immune infiltration was analyzed using TIMER, GEPIA database and TCGA data sets, and the relationship between NPM1 expression level and LUAD m6A modification and glycolysis was analyzed using TCGA and GEO data sets.

Results

NPM1 was overexpressed in a variety of tumors including LUAD, and the ROC curve showed that NPM1 had a certain accuracy in predicting the outcome of tumors and normal samples. The expression level of NPM1 in LUAD is significantly related to tumor stage and prognosis. The GO/KEGG enrichment analysis indicated that NPM1 was closely related to translational initiation, ribosome, structural constituent of ribosome, ribosome, Parkinson disease, and RNA transport. GSEA showed that the main enrichment pathway of NPM1-related differential genes was mainly related to mTORC1 mediated signaling, p53 hypoxia pathway, signaling by EGFR in cancer, antigen activates B cell receptor BCR leading to generation of second messengers, aerobic glycolysis and methylation pathways. The analysis of TIMER, GEPIA database and TCGA data sets showed that the expression level of NPM1 was negatively correlated with B cells and NK cells. The TCGA and GEO data sets analysis indicated that the NPM1 expression was significantly correlated with one m6A modifier related gene (HNRNPC) and five glycolysis related genes (ENO1, HK2, LDHA, LDHB and SLC2A1).

Conclusion

NPM1 is a prognostic biomarker involved in immune infiltration of LUAD and associated with m6A modification and glycolysis. NPM1 can be used as an effective target for diagnosis and treatment of LUAD.

Molecular Update and Evolving Classification of Large B-Cell Lymphoma

Simple Summary

The development of high-throughput technologies in recent years has increased our understanding of the molecular complexity of lymphomas, providing new insights into the pathogenesis of large B-cell neoplasms and identifying different molecular biomarkers with prognostic impact, that lead to the revision of the World Health Organization consensus classification of lymphomas. This review addresses the main histopathological and molecular features of large B-cells lymphomas, providing an overview of the main recent novelties introduced by the last update of the consensus classification.

Abstract

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell neoplasms with considerable clinical, biologic, and pathologic diversity. The application of high throughput technologies to the study of lymphomas has yielded abundant molecular data leading to the identification of distinct molecular identities and novel pathogenetic pathways. In light of this new information, newly refined diagnostic criteria have been established in the fourth edition of the World Health Organization (WHO) consensus classification of lymphomas, which was revised in 2016. This article reviews the histopathological and molecular features of the various aggressive B-cell lymphoma subtypes included in the updated classification.

Comprehensive Transcriptomic Analysis Reveals the Role of the Immune Checkpoint HLA-G Molecule in Cancers

Human leukocyte antigen G (HLA-G) is known as a novel immune checkpoint molecule in cancer; thus, HLA-G and its receptors might be targets for immune checkpoint blockade in cancer immunotherapy. The aim of this study was to systematically identify the roles of checkpoint HLA-G molecules across various types of cancer. ONCOMINE, GEPIA, CCLE, TRRUST, HAP, PrognoScan, Kaplan-Meier Plotter, cBioPortal, LinkedOmics, STRING, GeneMANIA, DAVID, TIMER, and CIBERSORT were utilized. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. In this study, we comprehensively analysed the heterogeneous expression of HLA-G molecules in various types of cancer and focused on genetic alterations, coexpression patterns, gene interaction networks, HLA-G interactors, and the relationships between HLA-G and pathological stage, prognosis, and tumor-infiltrating immune cells. We first identified that the mRNA expression levels of HLA-G were significantly upregulated in both most tumor tissues and tumor cell lines on the basis of in-depth analysis of RNAseq data. The expression levels of HLA-G were positively associated with those of the other immune checkpoints PD-1 and CTLA-4. Abnormal expression of HLA-G was significantly correlated with the pathological stage of some but not all tumor types. There was a significant difference between the high and low HLA-G expression groups in terms of overall survival (OS) or disease-free survival (DFS). The results showed that HLA-G highly expressed have positive associations with tumor-infiltrating immune cells in the microenvironment in most types of tumors (P<0.05). Additionally, we identified the key transcription factor (TF) targets in the regulation of HLA-G expression, including HIVEP2, MYCN, CIITA, MYC, and IRF1. Multiple mutations (missense, truncating, etc.) and the methylation status of the HLA-G gene may explain the differential expression of HLA-G across different tumors. Functional enrichment analysis showed that HLA-G was primarily related to T cell activation, T cell regulation, and lymphocyte-mediated immunity. The data may provide novel insights for blockade of the HLA-G/ILT axis, which holds potential for the development of more effective antitumour treatments.

The tweety Gene Family: From Embryo to Disease

The tweety genes encode gated chloride channels that are found in animals, plants, and even simple eukaryotes, signifying their deep evolutionary origin. In vertebrates, the tweety gene family is highly conserved and consists of three members—ttyh1, ttyh2, and ttyh3—that are important for the regulation of cell volume. While research has elucidated potential physiological functions of ttyh1 in neural stem cell maintenance, proliferation, and filopodia formation during neural development, the roles of ttyh2 and ttyh3 are less characterized, though their expression patterns during embryonic and fetal development suggest potential roles in the development of a wide range of tissues including a role in the immune system in response to pathogen-associated molecules. Additionally, members of the tweety gene family have been implicated in various pathologies including cancers, particularly pediatric brain tumors, and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. Here, we review the current state of research using information from published articles and open-source databases on the tweety gene family with regard to its structure, evolution, expression during development and adulthood, biochemical and cellular functions, and role in human disease. We also identify promising areas for further research to advance our understanding of this important, yet still understudied, family of genes.

Deregulated miRNAs Contribute to Silencing of B-Cell Specific Transcription Factors and Activation of NF-κB in Classical Hodgkin Lymphoma

Simple Summary

The role of transcriptionally deregulated miRNAs (microRNAs) in classical Hodgkin lymphoma (cHL) is still not fully understood. To address this issue, we have performed global miRNA expression profiling of commonly used cHL cell lines and we present a complete cHL miRNome (microRNome). Within this group, we identify miRNAs recurrently deregulated in cHL cell lines, and compare them to non-Hodgkin lymphoma cell lines and sorted normal CD77⁺ germinal centre B-cells. Moreover, we show that several of the recurrently overexpressed miRNAs in cHL cell lines, and also primary microdissected HRS (Hodgkin and Reed-Sternberg) cells, target known B-cell-related transcription factors and NF-κB inhibitors. These findings provide evidence that deregulated miRNAs contribute to the loss of B-cell phenotype and NF-κB activation observed in this lymphoma.

Abstract

A hallmark of classical Hodgkin lymphoma (cHL) is the attenuation of B-cell transcription factors leading to global transcriptional reprogramming. The role of miRNAs (microRNAs) involved in this process is poorly studied. Therefore, we performed global miRNA expression profiling using RNA-seq on commonly used cHL cell lines, non-Hodgkin lymphoma cell lines and sorted normal CD77⁺ germinal centre B-cells as controls and characterized the cHL miRNome (microRNome). Among the 298 miRNAs expressed in cHL, 56 were significantly overexpressed and 23 downregulated (p < 0.05) compared to the controls. Moreover, we identified five miRNAs (hsa-miR-9-5p, hsa-miR-24-3p, hsa-miR-196a-5p, hsa-miR-21-5p, hsa-miR-155-5p) as especially important in the pathogenesis of this lymphoma. Target genes of the overexpressed miRNAs in cHL were significantly enriched (p < 0.05) in gene ontologies related to transcription factor activity. Therefore, we further focused on selected interactions with the SPI1 and ELF1 transcription factors attenuated in cHL and the NF-ĸB inhibitor TNFAIP3. We confirmed the interactions between hsa-miR-27a-5p:SPI1, hsa-miR-330-3p:ELF-1, hsa-miR-450b-5p:ELF-1 and hsa-miR-23a-3p:TNFAIP3, which suggest that overexpression of these miRNAs contributes to silencing of the respective genes. Moreover, by analyzing microdissected HRS cells, we demonstrated that these miRNAs are also overexpressed in primary tumor cells. Therefore, these miRNAs play a role in silencing the B-cell phenotype in cHL.

ChoK-Full of Potential: Choline Kinase in B Cell and T Cell Malignancies

Aberrant choline metabolism, characterized by an increase in total choline-containing compounds, phosphocholine and phosphatidylcholine (PC), is a metabolic hallmark of carcinogenesis and tumor progression. This aberration arises from alterations in metabolic enzymes that control PC biosynthesis and catabolism. Among these enzymes, choline kinase α (CHKα) exhibits the most frequent alterations and is commonly overexpressed in human cancers. CHKα catalyzes the phosphorylation of choline to generate phosphocholine, the first step in de novo PC biosynthesis. CHKα overexpression is associated with the malignant phenotype, metastatic capability and drug resistance in human cancers, and thus has been recognized as a robust biomarker and therapeutic target of cancer. Of clinical importance, increased choline metabolism and CHKα activity can be detected by non-invasive magnetic resonance spectroscopy (MRS) or positron emission tomography/computed tomography (PET/CT) imaging with radiolabeled choline analogs for diagnosis and treatment monitoring of cancer patients. Both choline-based MRS and PET/CT imaging have also been clinically applied for lymphoid malignancies, including non-Hodgkin lymphoma, multiple myeloma and central nervous system lymphoma. However, information on how choline kinase is dysregulated in lymphoid malignancies is very limited and has just begun to be unraveled. In this review, we provide an overview of the current understanding of choline kinase in B cell and T cell malignancies with the goal of promoting future investigation in this area.

Usefulness of BATF3 Immunohistochemistry in Diagnosing Classical Hodgkin Lymphoma

It is well recognized that the AP-1 transcription factor BATF3 is constitutively expressed in Hodgkin/Reed-Sternberg (HRS) cells, but its potential as a diagnostic marker for classical Hodgkin lymphoma (cHL) has not yet been addressed. In this study, we performed immunohistochemistry and analyzed the BATF3 expression in lymphoma cells on 218 lymphoma samples belonging to 14 different lymphoma entities. We observed varying degrees of BATF3 expression in nearly half of the cases (n = 100) with BATF3 expression being a constitutive feature of cHL (n = 53) and anaplastic large cell lymphoma (ALCL). By scoring BATF3 expression (BATF3-score) we observed constitutively high BATF3-scores in cHL and ALCL and low to moderate BATF3-scores in all other entities examined. Western blot analysis confirmed BATF3 protein expression in cell lysates from cHL cell lines (n = 7). Thus, BATF3 can be considered a useful IHC marker for the diagnosis of cHL as it is highly sensitive and sufficiently specific when analyzed by BATF3-scoring.

Pitfalls in the Diagnosis of Nodular Lymphocyte Predominant Hodgkin Lymphoma: Variant Patterns, Borderlines and Mimics

Simple Summary

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare lymphoma containing infrequent tumor cells (LP cells) in a background of non-neoplastic cells. Some cases of NLPHL can recur or progress to a more aggressive lymphoma, such as diffuse large B-cell lymphoma. Awareness of the different appearances of NLPHL and its overlap with other lymphomas are important for the appropriate diagnosis, classification and research. This article discusses the conceptual framework and guidelines for the diagnosis of NLPHL, and how NLPHL can be best separated from its mimics. Emerging data in the field point to genetic changes in LP cells that are shaped by immune mechanisms. In addition, non-neoplastic cells in the background of LP cells also appear to play an important role. Further investigation is necessary to fully understand the biology of NLPHL and personalize cancer care for patients affected by this lymphoma.

Abstract

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) represents approximately 5% of Hodgkin lymphoma and typically affects children and young adults. Although the overall prognosis is favorable, variant growth patterns in NLPHL correlate with disease recurrence and progression to T-cell/histiocyte-rich large B-cell lymphoma or frank diffuse large B-cell lymphoma (DLBCL). The diagnostic boundary between NLPHL and DLBCL can be difficult to discern, especially in the presence of variant histologies. Both diagnoses are established using morphology and immunophenotype and share similarities, including the infrequent large tumor B-cells and the lymphocyte and histiocyte-rich microenvironment. NLPHL also shows overlap with other lymphomas, particularly, classic Hodgkin lymphoma and T-cell lymphomas. Similarly, there is overlap with non-neoplastic conditions, such as the progressive transformation of germinal centers. Given the significant clinical differences among these entities, it is imperative that NLPHL and its variants are carefully separated from other lymphomas and their mimics. In this article, the characteristic features of NLPHL and its diagnostic boundaries and pitfalls are discussed. The current understanding of genetic features and immune microenvironment will be addressed, such that a framework to better understand biological behavior and customize patient care is provided.

Transcriptome integration analysis and specific diagnosis model construction for Hodgkin's lymphoma, diffuse large B-cell lymphoma, and mantle cell lymphoma

Transcriptome differences between Hodgkin's lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and mantle cell lymphoma (MCL), which are all derived from B cell, remained unclear. This study aimed to construct lymphoma-specific diagnostic models by screening lymphoma marker genes. Transcriptome data of HL, DLBCL, and MCL were obtained from public databases. Lymphoma marker genes were screened by comparing cases and controls as well as the intergroup differences among lymphomas. A total of 9 HL marker genes, 7 DLBCL marker genes, and 4 MCL marker genes were screened in this study. Most HL marker genes were upregulated, whereas DLBCL and MCL marker genes were downregulated compared to controls. The optimal HL-specific diagnostic model contains one marker gene (MYH2) with an AUC of 0.901. The optimal DLBCL-specific diagnostic model contains 7 marker genes (LIPF, CCDC144B, PRO2964, PHF1, SFTPA2, NTS, and HP) with an AUC of 0.951. The optimal MCL-specific diagnostic model contains 3 marker genes (IGLV3-19, IGKV4-1, and PRB3) with an AUC of 0.843. The present study reveals the transcriptome data-based differences between HL, DLBCL, and MCL, when combined with other clinical markers, may help the clinical diagnosis and prognosis.

CRL4AMBRA1 is a master regulator of D-type cyclins

D-type cyclins are central regulators of the cell division cycle and are among the most frequently deregulated therapeutic targets in human cancer¹, but the mechanisms that regulate their turnover are still being debated^2,3. Here, by combining biochemical and genetics studies in somatic cells, we identify CRL4^AMBRA1 (also known as CRL4^DCAF3) as the ubiquitin ligase that targets all three D-type cyclins for degradation. During development, loss of Ambra1 induces the accumulation of D-type cyclins and retinoblastoma (RB) hyperphosphorylation and hyperproliferation, and results in defects of the nervous system that are reduced by treating pregnant mice with the FDA-approved CDK4 and CDK6 (CDK4/6) inhibitor abemaciclib. Moreover, AMBRA1 acts as a tumour suppressor in mouse models and low AMBRA1 mRNA levels are predictive of poor survival in cancer patients. Cancer hotspot mutations in D-type cyclins abrogate their binding to AMBRA1 and induce their stabilization. Finally, a whole-genome, CRISPR-Cas9 screen identified AMBRA1 as a regulator of the response to CDK4/6 inhibition. Loss of AMBRA1 reduces sensitivity to CDK4/6 inhibitors by promoting the formation of complexes of D-type cyclins with CDK2. Collectively, our results reveal the molecular mechanism that controls the stability of D-type cyclins during cell-cycle progression, in development and in human cancer, and implicate AMBRA1 as a critical regulator of the RB pathway.

Karonudib has potent anti-tumor effects in preclinical models of B-cell lymphoma

Chemo-immunotherapy has improved survival in B-cell lymphoma patients, but refractory/relapsed diseases still represent a major challenge, urging for development of new therapeutics. Karonudib (TH1579) was developed to inhibit MTH1, an enzyme preventing oxidized dNTP-incorporation in DNA. MTH1 is highly upregulated in tumor biopsies from patients with diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma, hence confirming a rationale for targeting MTH1. Here, we tested the efficacy of karonudib in vitro and in preclinical B-cell lymphoma models. Using a range of B-cell lymphoma cell lines, karonudib strongly reduced viability at concentrations well tolerated by activated normal B cells. In B-cell lymphoma cells, karonudib increased incorporation of 8-oxo-dGTP into DNA, and prominently induced prometaphase arrest and apoptosis due to failure in spindle assembly. MTH1 knockout cell lines were less sensitive to karonudib-induced apoptosis, but were displaying cell cycle arrest phenotype similar to the wild type cells, indicating a dual inhibitory role of the drug. Karonudib was highly potent as single agent in two different lymphoma xenograft models, including an ABC DLBCL patient derived xenograft, leading to prolonged survival and fully controlled tumor growth. Together, our preclinical findings provide a rationale for further clinical testing of karonudib in B-cell lymphoma.

Molecular biology of Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is unique among lymphoid malignancies in several key biological features. (i) The Hodgkin and Reed-Sternberg (HRS) tumor cells are rare among an extensive and complex microenvironment. (ii) They derive from B cells, but have largely lost the B-cell typical gene expression program. (iii) Their specific origin appears to be pre-apoptotic germinal center (GC) B cells. (iv) They consistently develop bi- or multinucleated Reed-Sternberg cells from mononuclear Hodgkin cells. (v) They show constitutive activation of numerous signaling pathways. Recent studies have begun to uncover the basis of these specific features of cHL: HRS cells actively orchestrate their complex microenvironment and attract many distinct subsets of immune cells into the affected tissues, to support their survival and proliferation, and to create an immunosuppressive environment. Reed-Sternberg cells are generated by incomplete cytokinesis and refusion of Hodgkin cells. Epstein-Barr virus (EBV) plays a major role in the rescue of crippled GC B cells from apoptosis and hence is a main player in early steps of lymphomagenesis of EBV⁺ cHL cases. The analysis of the landscape of genetic lesions in HRS cells so far did not reveal any highly recurrent HRS cell-specific lesions, but major roles of genetic lesions in members of the NF-κB and JAK/STAT pathways and of factors of immune evasion. It is perhaps the combination of the genetic lesions and the peculiar cellular origin of HRS cells that are disease defining. A combination of such genetic lesions and multiple cellular interactions with cells in the microenvironment causes the constitutive activation of many signaling pathways, often interacting in complex fashions. In nodular lymphocyte predominant Hodgkin lymphoma, the GC B cell-derived tumor cells have largely retained their typical GC B-cell expression program and follicular microenvironment. For IgD-positive cases, bacterial antigen triggering has recently been implicated in early stages of its pathogenesis.