Flow Cytometry for Non-Hodgkin and Hodgkin Lymphomas.

Multiparametric flow cytometry is a powerful diagnostic tool that permits rapid assessment of cellular antigen expression to quickly provide immunophenotypic information suitable for disease classification. This chapter describes a general approach for the identification of abnormal lymphoid populations by flow cytometry, including B, T, NK, and Hodgkin lymphoma cells suitable for the clinical and research environment. Knowledge of the common patterns of antigen expression of normal lymphoid cells is critical to permit identification of abnormal populations at disease presentation and for minimal residual disease assessment. We highlight an overview of procedures for processing and immunophenotyping non-Hodgkin B- and T-cell lymphomas and also describe our strategy for the sensitive and specific diagnosis of classic Hodgkin lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and T-cell/histiocyte-rich large B-cell lymphoma.

Laser-Based Microdissection of Single Cells from Tissue Sections and PCR Analysis of Rearranged Immunoglobulin Genes from Isolated Normal and Malignant Human B Cells.

Normal and malignant B cells carry rearranged immunoglobulin (Ig) variable region genes, which due to their practically limitless diversity represent ideal clonal markers for these cells. We describe here an approach to isolate single cells from frozen tissue sections by microdissection using a laser-based method. From the DNA of the isolated cells, rearranged IgH and Igκ genes are amplified in a semi-nested PCR approach, using a collection of IGV gene subgroup-specific primers recognizing nearly all IGV genes together with primers for the J genes. By sequence analysis of IGV region genes from distinct cells, the clonal relationship of the B-lineage cells can unequivocally be determined and related to the histological distribution of the cells. The approach is also useful to determine V, D and J gene usage. Moreover, the presence and pattern of somatic IGV gene mutations give valuable insight into the differentiation stage of the B cells.

MRD Detection in B-Cell Non-Hodgkin Lymphomas Using Ig Gene Rearrangements and Chromosomal Translocations as Targets for Real-Time Quantitative PCR and ddPCR.

Minimal residual disease (MRD) diagnostics is of high clinical relevance in patients with indolent B-cell non-Hodgkin lymphomas (B-NHL), B-cell chronic lymphocytic leukemia (CLL), and multiple myeloma and serves as a surrogate parameter to evaluate treatment effectiveness and long-term prognosis. Real-time quantitative PCR (RQ-PCR) targeting circulating lymphoma cells is still the gold standard for MRD detection in indolent B-NHL and currently the most sensitive and the most broadly applied method in follicular lymphoma (FL) and mantle cell lymphoma (MCL). Alternatively, droplet digital PCR (ddPCR) can be used for MRD monitoring in multiple myeloma, mantle cell lymphoma, CLL, and FL with comparable sensitivity, accuracy, and reproducibility.The most broadly applicable MRD target in B-NHL is the junctional regions of the rearranged immunoglobulin heavy (IGH) and light chain genes. Complete and incomplete IGH and additionally IG kappa light chain rearrangements can be used as targets for MRD. Next-generation sequencing (NGS) of IG-rearrangements (IG-NGS) as new sequencing-based technology can overcome the limitation of PCR-based approaches and has a potential for higher sensitivity. Chromosomal translocations like the t(14;18)(q32;q21) translocation associated with IGH::BCL2 fusion in FL and t(11;14)(q13;q32) translocation in MCL leading to the IGH::CCND1 fusion can be used as MRD target in selected lymphoma subtypes. In patients with CLL, both flow-cytometry and RQ-PCR are equally suited for MRD assessment as long as a sensitivity of 10-4 is achieved.MRD diagnostics targeting the IG loci is complex and requires extensive knowledge and experience because the junctional regions of each clonal rearranged gene have to be identified before the patient-specific PCR assays can be designed for MRD monitoring. In addition, the presence and load of somatic hypermutation within the rearranged IGH gene occurring during B-cell development of germinal center and post-germinal center B-cell lymphomas may hamper appropriate primer binding leading to false-negative results. The translocations mentioned above have the advantage that consensus forward primers and probes, both placed in the breakpoint regions of chromosome 18 in FL and chromosome 11 in MCL, can be used in combination with a reverse primer placed in the IGH joining region of chromosome 14. PCR-based methods using allele-specific primers can reach a high sensitivity of up to 10-5. This chapter provides all relevant background information and technical aspects for the complete laboratory process from detection of the clonal IG gene rearrangements and the chromosomal translocations at diagnosis to the actual MRD measurements in clinical follow-up samples of B-NHL. However, it should be noted that MRD diagnostics for clinical treatment protocols has to be accompanied by regular international quality control rounds to ensure the reproducibility and reliability of the MRD results. This is available by the EuroMRD network ( https://euromrd.org ), a subgroup of ESHLO ( https://eslho.org ).

Single Cell VDJ Sequencing of Normal and Malignant B and T Cells.

Recent developments in single cell sequencing technologies enable researchers to examine heterogeneity of cell types and subclusters even deeper. First assays were only available for transcriptome analysis of up to 10,000 cells, but nowadays up to 60,000 cells or even more can be analyzed. Whereas initially only analysis of mRNA expression was possible, currently single cell methods multiplied, with extension of assays for examination of surface molecule expression, DNA accessibility (ATAC-seq), antigen specificity, and B or T cell receptor repertoires. Also, spatial transcriptomics or CRISPR screenings, augmenting classical CRISPR/Cas9 screens by combining them with transcriptomic data at single cell level, can be evaluated. The composition of B and T cell clones-of malignant cells in lymphomas and leukemia, as well as of infiltrating B or T cell clones in other types of cancer-is especially important in tumor research, as these clones may give valuable hints for tumor development and control. This chapter presents detailed methods for implementation and analysis of single cell B and/or T cell receptor repertoire sequencing on the Chromium system from 10× Genomics and the Rhapsody™ system from BD Bioscience.

Single-Cell Transcriptomic Analysis of Normal and Malignant B Cells.

In the past decade, single-cell (sc) transcriptomics has overcome the limitations of bulk analysis by measuring gene expression in individual cells, not just a population average. This can identify diverse cell types and states within a sample with high resolution, even without prior purification. Various technologies exist, each with its own capture, barcoding, and library preparation methods. This chapter focuses on the analysis of normal and malignant mature B cells using the 10× Genomics 5' sc-gene expression in parallel with B cell immune repertoire profiling. By integrating the gene expression data from similar cells, the complete transcriptome for each population can be reconstructed, while the identification of the expressed immunoglobulin genes allows investigating clonotype evolution and the detection of tumor clones that share the same clonally rearranged B cell receptor sequence. Researchers are guided through both the experimental protocols and data analysis with a comprehensive, step-by-step walkthrough of how to use some of the more popular single-cell software tools.

Unique endoscopic features of primary biliary diffuse large B-cell lymphoma: A case report with literature review (with video).

A 67-year-old man visited our hospital complaining of dark-colored urine and upper abdominal pain. Magnetic resonance cholangiopancreatography showed stricture of the distal bile duct, and contrast-enhanced computed tomography showed irregular thickening of the distal bile duct wall. However, no enlarged lymph nodes, pancreatic tumors, or other neoplastic lesions were apparent around the bile duct. Endoscopic ultrasonography and intraductal ultrasonography showed irregular thickening of the inner hypoechoic layer without the disappearance of the innermost thin hyperechoic layer. On the basis of these findings, we considered that the bile duct lesion was of non-epithelial origin. Thus, we repeatedly performed bile duct biopsies from the same site under fluoroscopy to obtain a sample of the submucosal tissue. The pathological diagnosis was diffuse large B-cell lymphoma, and the patient received systemic chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). After six courses of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone, positron emission tomography-computed tomography showed the disappearance of 18-fluorodeoxyglucose uptake in the bile duct and endoscopic retrograde cholangiography showed improvement of the bile duct stricture. Endoscopic findings and repeated biopsies were useful in making the diagnosis of primary biliary diffuse large B-cell lymphoma.

Stereotyped B-Cell Receptor Immunoglobulins in B-Cell Lymphomas.

Thorough examination of clonotypic B-cell receptor immunoglobulin (BcR IG) gene rearrangement sequences in patients with mature B-cell malignancies has revealed significant repertoire restrictions, leading to the identification of subsets of patients expressing highly similar, stereotyped BcR IG. This discovery strongly suggests selection by common epitopes or classes of structurally similar epitopes in the development of these tumors. Initially observed in chronic lymphocytic leukemia (CLL), where the stereotyped fraction accounts for a substantial fraction of patients, stereotyped BcR IGs have also been identified in other mature B-cell malignancies, including mantle cell lymphoma (MCL) and splenic marginal zone lymphoma (SMZL).Further comparisons across different entities have indicated that stereotyped IGs are predominantly "disease-biased," indicating distinct immune pathogenetic trajectories. Notably, accumulating evidence suggests that molecular subclassification of mature B-cell malignancies based on BcR IG stereotypy holds biological and clinical relevance. Particularly in CLL, patients belonging to the same subset due to the expression of a specific stereotyped BcR IG exhibit consistent biological backgrounds and clinical courses, especially for major and extensively studied subsets. Therefore, robust assignment to stereotyped subsets may aid in uncovering mechanisms underlying disease initiation and progression, as well as refining patient risk stratification. In this chapter, we offer an overview of recent studies on BcR IG stereotypy in mature B-cell malignancies and delineate past and present methodological approaches utilized for the identification of stereotyped BcR IG.

B Cell Differentiation and the Origin and Pathogenesis of Human B Cell Lymphomas.

Immunoglobulin (IG) gene remodeling by V(D)J recombination plays a central role in the generation of normal B cells, and somatic hypermutation and class switching of IG genes are key processes during antigen-driven B cell differentiation in the germinal center reaction. However, errors of these processes are involved in the development of B cell lymphomas. IG locus-associated translocations of proto-oncogenes are a hallmark of many B cell malignancies. Additional transforming events include inactivating mutations in various tumor suppressor genes and also latent infection of B cells with viruses, such as Epstein-Barr virus. Most B cell lymphomas require B cell antigen receptor expression, and in several instances chronic antigenic stimulation plays a role in lymphoma development and/or sustaining tumor growth. Often, survival and proliferation signals provided by other cells in the microenvironment are a further critical factor in lymphoma development and pathophysiology. Most B cell malignancies derive from germinal center B cells, most likely due to the high proliferative activity of these B cells and aberrant mutations caused by their naturally active mutagenic processes.

Regulation of B-cell function by miRNAs impacting Systemic lupus erythematosus progression.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease marked by abnormal B-cell proliferation and increased autoantibodies. miRNAs play a crucial role in regulating B-cell dysfunction and SLE pathology. miRNAs influence DNA methylation, B-cell activation, and gene expression, contributing to SLE pathogenesis. miRNAs impact B cells through key processes like proliferation, differentiation, tolerance, and apoptosis. miRNAs also exacerbate inflammation and immune responses by modulating Interleukin 4 (IL-4), IL-6, and interferon cytokines. Autophagy, a key degradation mechanism, is also regulated by specific miRNAs that impact SLE pathology. This article explores the role of multiple miRNAs in regulating B-cell development, proliferation, survival, and immune responses, influencing SLE pathogenesis. miRNAs like miR-23a, the miR-17 âˆ¼ 92 family, and miR-125b/miR-221 affect B-cell development by regulating transcription factors, signaling pathways, and cell cycle genes. miRNAs such as miR-181a-5p and miR-23a-5p are differentially regulated across developmental stages, emphasizing their complex regulatory roles in B-cell biology. This article synthesizes miRNA-B cell interactions to offer new strategies and directions for SLE diagnosis and treatment.

Upregulation of miR­6747­3p affects red blood cell lineage development and induces fetal hemoglobin expression by targeting BCL11A in ß­thalassemia.

In ß­thalassemia, excessive α­globin chain impedes the normal development of red blood cells resulting in anemia. Numerous miRNAs, including miR­6747­3p, are aberrantly expressed in ß­thalassemia major (ß­TM), but there are no reports on the mechanism of miR­6747­3p in regulating red blood cell lineage development and fetal hemoglobin (HbF) expression. In the present study, RT­qPCR was utilized to confirm miR­6747­3p expression in patients with ß­TM and the healthy controls. Electrotransfection was employed to introduce the miR­6747­3p mimic and inhibitor in both HUDEP­2 and K562 cells, and red blood cell lineage development was evaluated by CCK­8 assay, flow cytometry, Wright­Giemsa staining and Benzidine blue staining. B­cell lymphoma/leukemia 11A (BCL11A) was selected as a candidate target gene of miR­6747­3p for further validation through FISH assay, dual luciferase assay and Western blotting. The results indicated that miR­6747­3p expression was notably higher in patients with ß­TM compared with healthy controls and was positively related to HbF levels. Functionally, miR­6747­3p overexpression resulted in the hindrance of cell proliferation, promotion of cell apoptosis, facilitation of cellular erythroid differentiation and γ­globin expression in HUDEP­2 and K562 cells. Mechanistically, miR­6747­3p could specifically bind to the 546­552 loci of BCL11A 3'­UTR and induce γ­globin expression. These data indicate that upregulation of miR­6747­3p affects red blood cell lineage development and induces HbF expression by targeting BCL11A in ß­thalassemia, highlighting miR­6747­3p as a potential molecular target for ß­thalassemia therapy.

Hematopoietic Neoplasms of the Sinonasal Tract.

Hematologic malignancies are one of the more common neoplasms to occur in the sinonasal tract and include a wide range of entities, including mature and immature B cell and T cell neoplasms as well as plasma cell dyscrasias and histiocytic disorders. CD45 expression can be helpful in identifying many, but not all, hematopoietic neoplasms in the sinonasal tract, and more extensive immunophenotyping, including EBV in situ hybridization, as well as correlation with genetic results and clinical features may be required for diagnosis.

Flow cytometry identifies changes in peripheral and intrathecal lymphocyte patterns in CNS autoimmune disorders and primary CNS malignancies.

BACKGROUND: Immune dysregulation is a hallmark of autoimmune diseases of the central nervous system (CNS), characterized by an excessive immune response, and primary CNS tumors (pCNS-tumors) showing a highly immunosuppressive parenchymal microenvironment. METHODS: Aiming to provide novel insights into the pathogenesis of CNS autoimmunity and cerebral tumor immunity, we analyzed the peripheral blood (PB) and cerebrospinal fluid (CSF) of 81 autoimmune limbic encephalitis (ALE), 148 relapsing-remitting multiple sclerosis (RRMS), 33 IDH-wildtype glioma, 9 primary diffuse large B cell lymphoma of the CNS (CNS-DLBCL), and 110 controls by flow cytometry (FC). Additionally, an in-depth immunophenotyping of the PB from an independent cohort of 20 RRMS and 18 IDH-wildtype glioblastoma patients compared to 19 controls was performed by FC combined with unsupervised computational approaches. RESULTS: We identified alterations in peripheral and intrathecal adaptive immunity, mainly affecting the T cell (Tc) but also the B cell (Bc) compartment in ALE, RRMS, and pCNS-tumors compared to controls. ALE, RRMS, and pCNS-tumors featured higher expression of the T cell activation marker HLA-DR, which was even more pronounced in pCNS-tumors than in ALE or RRMS. Glioblastoma patients showed signs of T cell exhaustion that were not visible in RRMS patients. In-depth characterization of the PB revealed differences mainly in the T effector and memory compartment between RRMS and glioblastoma patients and similar alterations in the Bc compartment, including atypical Bc, CD19+CD20- double negative Bc, and plasma cells. PB and CSF mFC together with CSF routine parameters could reliably differentiate ALE and RRMS from pCNS-tumors facilitating early diagnosis and treatment. CONCLUSIONS: ALE, RRMS, and pCNS-tumors show distinct but partially overlapping changes mainly in HLA-DR+ Tc, memory Tc, exhausted Tc, and Bc subsets providing insights into disease pathogenesis. Moreover, mFC shows diagnostic potential facilitating early diagnosis and treatment.

Real-world efficacy of chidamide plus R-CHOP in newly diagnosed double-expressor diffuse large B-cell lymphoma.

Background: Approximately 20%-30% of diffuse large B-cell lymphoma (DLBCL) cases are classified as double-expressor lymphoma (DEL), characterized by the co-expression of the MYC and BCL2 proteins. However, the most effective therapeutic strategy for DEL remains unidentified. Objectives: To evaluate the efficacy of a novel histone deacetylase inhibitor, chidamide, in combination with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (CR-CHOP) in the treatment of DEL. Design: This was a retrospective study. Methods: This study included 62 DEL patients from December 2016 to December 2020. All patients were administered a first-line treatment with CR-CHOP. The short-term efficacy, survival status, and adverse reactions in this population were observed, and the prognostic factors were analyzed. Results: The median age was 53.9 years (range, 19-77). All patients received a median of six cycles (range, 1-8) of treatment, with 79.0% achieving complete response (CR) and an overall response rate of 88.7%. With a median follow-up of 45.5 months (range, 1-82), the median progression-free survival (PFS) and median overall survival (OS) had not yet been reached. However, the 3-year PFS rate was 71% (95% CI: 61-83), the 3-year OS rate was 87% (95% CI: 79-96), the 5-year PFS rate was 67% (95% CI: 55-80), and the 5-year OS rate was 85% (95% CI: 77-95). Age and autologous stem cell transplantation after CR or partial response were independent prognostic factors for PFS, while various clinical factors were not associated with OS outcomes. The most common grades 3-4 hematologic and nonhematologic toxicity were leukopenia (46.7%) and infection (21%), respectively. Conclusion: This long-term follow-up study indicates that CR-CHOP in untreated DLBCL with the DEL phenotype demonstrates high short-term efficacy and safety as well as promising survival outcomes.

Characterization and ontogeny of a novel lymphoid follicle inducer cell during development of the bursa of Fabricius.

The avian bursa of Fabricius (BF) is a primary lymphoid organ, where B-cell development occurs within bursal follicles of epithelial origin. During embryogenesis the epithelial anlage of the BF emerges as a diverticulum of the cloaca surrounded by undifferentiated tail bud mesenchyme. While it is believed that the epithelial-mesenchymal BF primordium provides a selective microenvironment for developing B cells, the initial events inducing lymphoid follicle formation are not fully elucidated. Using wild type and CSF1R-eGFP transgenic chick embryos, we find that separate B cell, macrophage and dendritic cell precursors enter the BF mesenchyme, migrate to the surface epithelium, and colonize the lymphoid follicle buds. Detailed immunocytochemical characterization revealed a novel EIV-E12+ blood-borne cell type, colonizing the surface epithelium of the BF rudiment before the entry of myeloid and lymphoid lineages and the appearance of this cell type coincides with the onset of follicle bud formation. Chick-duck chimeras and chick-quail tissue recombination experiments suggest that EIV-E12+ cells represent a transient lymphoid inducer cell population. They are not dendritic or B cells precursors, and they are capable of follicle bud induction in both dendritic cell- and B cell-depleted bursae.

Identification of oxidative stress-related hub genes for predicting prognosis in diffuse large B-cell lymphoma.

BACKGROUND: Oxidative stress is a cellular characteristic that might induce the proliferation and differentiation of tumor cells and promote tumor progression in diffuse large B-cell lymphoma (DLBCL). METHODS: The DLBCL gene sequencing dataset, tumor mutation burden data, copy number variation data of Somatic cell mutation data in TCGA were downloaded for data training analysis, along with four DLBCL datasets in GEO for validation analysis. The known oxidative stress related genes (OSRGs) were collected from websites. The weighted gene co-expression network analysis (WGCNA) was conducted on the TCGA DLBCL dataset to obtain gene modules related to oxidative stress and intersected with the known OSRGs to obtain the hub genes, which were used to perform consensus clustering on the samples to obtain new phenotypes. Next, the prognosis related OSRGs were selected through regression analysis algorithms and key genes were identified. These genes were used to establish the prognostic risk model and predictive model, and to compare functional and pathway differences among different risk groups. RESULTS: Through website search, we obtained 297 known OSRGs, and after intersecting with WGCNA results, we obtained 26 OSRGs. The TCGA-DLBC samples were clustered into 2 subtypes with these genes and there were significant differences in immune infiltration between subtypes. After regression analysis, we obtained a total of four key genes, BMI1, CDKN1A, NOX1, and SESN1. The risk prediction model established with these four genes as variables has accurate prognostic prediction ability. The key genes interact with 65 miRNAs, 57 TFs, 47 RBPs, and 62 drugs, respectively, and are closely related to immune infiltration of the disease. Among them, CDKN1A and SESN1 had the highest variability. CONCLUSIONS: The key genes involved in oxidative stress could predict the prognosis of DLBCL and potentially become therapeutic targets.

The metabolic role of lactate dehydrogenase in the growth of diffuse large B cell lymphoma.

Lactate dehydrogenase (LDHA) activation induces tumorigenesis by activating tumor proliferation, growth, invasion, and metastasis. Whether LDHA mediates tumor metabolism that upon diffuse large B-cell lymphoma (DLBCL) occur remains unknown. Here, we investigated how LDHA adopt tumor metabolism after activation to regulate DLBCL-inducible. We investigated LDHA is highly expressed in peripheral blood mononuclear cells (PBMCs) of DLBCL patients. Knockdown of LDHA results in an increase in the apoptosis of cells, suppression of cell growth and migration in OCI-Ly1 and OCI-Ly10 cells. We show that LDHA gains a canonical enzyme activity to produce lactate and triggers NAD + in DLBCL cells. Furthermore, p-STAT5 was identified as a downstream target of LDHA, and the p-STAT5 protein level was significantly reduced related to decreased LDHA protein expression. Collectively, our findings identify the oncogenic role of LDHA in DLBCL and suggest that LDHA can be considered as a pivotal prognostic biomarker and a potential therapeutic target.

Cellular therapy in older adults with relapsed/refractory diffuse large B-cell lymphoma.

Relapsed/Refractory (R/R) diffuse large B-cell lymphoma (DLBCL) is an aggressive disease with poor prognosis and limited therapeutic options. High-dose chemotherapy with autologous hematopoietic stem cell transplantation (autoHCT) was historically the curative-intent treatment for patients who demonstrated chemosensitivity to salvage therapy. However, a significant portion of patients do not make it autoHCT due to disease progression or overall fitness and eligibility. This is of particular concern in the older adult population. In recent years, significant advances in cellular therapies including chimeric antigen receptor (CAR) T-cells and bispecific antibodies, in addition to improvement in autoHCT tolerability, have allowed for additional treatment options for patients with R/R DLBCL. These novel therapies offer the potential for durable remissions and cure, and should be considered in older patients. We present a review focused on the safety and efficacy of cellular therapies in the older adult population with R/R DLBCL.

The usefulness of B-cell lymphoma-2 immunohistochemical stain in the differentiation between reactive atypia and dysplasia/carcinoma in the gallbladder.

Objective: The differentiation between reactive atypical changes and dysplasia/carcinoma in the daily cases of cholecystectomies is a routine histopathological challenge. Up to our knowledge, no immunohistochemical marker can definitely differentiate between these two changes. Many promising markers have been proposed to be helpful tools in this situation. One of them is B-cell lymphoma-2 (BCL-2) immunohistochemical stain. Therefore, this study aims to evaluate its usefulness as a marker that might be helpful in such challenging cases. Methods: From the archive of the histopathology laboratories of Qassim University Medical City and King Fahad Specialist Hospital in Qassim, five dysplastic/neoplastic gallbladder cases were collected (in the shape of formalin-fixed, paraffin-embedded blocks) as well as five cholecystitis with reactive atypical changes cases. Two slides from each block were prepared: One was stained with H&E and the other was stained immunohistochemically with BCL-2. The slides were evaluated by two histopathologist consultants in the same sitting using multiheaded microscope to confirm the original diagnosis and to evaluate the BCL-2 staining. Results: Five dysplastic/carcinoma cases and five cholecystitis with reactive atypia were collected. The original diagnoses were confirmed by two pathologists. They also confirmed that all the BCL-2 stained slides (with the exception of one reactive case) were negative for BCL-2 immunohistochemical stain. Conclusion: BCL-2 immunohistochemical stain is not a promising marker in the differentiation between reactive epithelium and dysplasia/carcinoma in the gallbladder.

Primary Refractory Discordant Diffuse Large B-Cell and Classical Hodgkin Lymphoma.

Discordant lymphomas are defined as two or more distinct pathological lymphomas occurring in the same patient. Due to the rarity of discordant lymphomas, which is due in large part to the difficulty in establishing the diagnosis, the literature is limited to small case series and case reports. Consequently, guidelines on therapeutic strategies are lacking. This article presented a case of primary refractory discordant large B-cell lymphoma and classic Hodgkin lymphoma in a young man based on cervical node and mediastinal mass biopsy, respectively. This case illustrates the difficulty in establishing the diagnosis, which ultimately warranted a high index of clinical suspicion and pursuit of multiple sequential biopsies, as well as a novel treatment strategy using an immune checkpoint inhibitor.

Identification of ferroptosis-related genes associated with diffuse large B-cell lymphoma via bioinformatics and machine learning approaches.

Ferroptosis has emerged as a critical mechanism in the development and progression of various tumors, particularly diffuse large B-cell lymphoma (DLBCL). However, the thorough characterization of ferroptosis-related genes in DLBCL remains inadequately explored. We retrieved datasets associated with DLBCL and ferroptosis gene sets from the Gene Expression Omnibus (GEO) database and the Ferroptosis Database (FerrDb), resulting in the identification of 27 differentially expressed ferroptosis-related genes (DE-FRGs) linked to DLBCL. Utilizing the LASSO and Support Vector Machine Recursive Feature Elimination (SVW-RFE) algorithms, we identified 10 genes-MT1G, MTOR, BRD4, ACO1, SAT1, PEBP1, LPIN1, ATM, SRXN1, and PRDX1-as key biomarker candidates with significant diagnostic potential. Functional enrichment analyses revealed that these biomarker genes are likely involved in regulating several critical biological pathways implicated in DLBCL pathogenesis, including immune response, oxidative phosphorylation, and cell cycle regulation. Moreover, we identified 246 potential therapeutic agents targeting these 10 biomarker genes. Concurrently, competitive endogenous RNA (ceRNA) network analysis uncovered a complex regulatory network centered on the identified biomarker genes. Additionally, CIBERSORT analysis highlighted notable alterations in the immune microenvironment of DLBCL patients. We propose a diagnostic strategy that provides novel insights into the molecular mechanisms underlying DLBCL. Nevertheless, further validation of the practical value of this strategy for DLBCL diagnosis is necessary before its clinical application.