Long-Term Recurrence-Free Survival of an Elderly Patient With Diffuse Large B-cell Lymphoma in the Setting of Rituximab-Containing Therapy and a Natural History of Gastric Adenocarcinoma.

Diffuse large B-cell lymphoma (DLBCL) is a high-grade malignancy. We present a case of a 97-year-old female with gastric cancer and DLBCL in whom remission with rituximab-containing minimum chemotherapy was sustained for 10 years. As she had severe adverse effects, she refused further treatments for both tumors. Ten years after the initial treatment, examinations showed several tumors in the lungs, the right pleura, and the liver, as well as advanced gastric cancer. She eventually passed away, and the autopsy revealed that multiple tumors were not lymphoma, but adenocarcinoma. This case report is a valuable addition to the literature as it analyzes whether rituximab-containing minimum chemotherapy is effective for elderly DLBCL and delineates the natural history of gastric cancer.

Analysis of Histologic, Immunohistochemical and Genomic Features of Large B Cell Lymphoma Tumors May Predict Response to Polatuzumab Vedotin Based Therapy in Patients With Relapsed/Refractory Disease.

BACKGROUND: Large B cell lymphoma (LBCL) is the most common form of lymphoma. Polatuzumab vedotin (polatuzumab) is an effective therapy for patients diagnosed with LBCL; however, only limited information regarding pathologic features detected by clinical laboratory assays is available to determine which patients are most likely to benefit from polatuzumab based therapies. PATIENTS AND METHODS: We collected data from real world patients with relapsed or refractory LBCL whose tumors underwent next generation sequencing and were treated with polatuzumab based therapy at a single large academic cancer center. Tumor and patient characteristics were analyzed to look for factors that predict response to polatuzumab based therapies. RESULTS: We identified high grade B cell lymphoma (HGBL) -NOS or MYC/BCL2 histology and presence of MYC rearrangement as factors that predict inferior response to polatuzumab based therapy. Patients with germinal center B cell of origin (GCB COO) LBCL without these factors had a high response rate (73%) to polatuzumab based therapy. CONCLUSION: In a single center real world retrospective analysis of R/R LBCL patients with available genomic data, polatuzumab based therapy may be less effective in patients with HGBL-NOS or MYC/BCL2 histology and MYC rearrangements, but not in patients with GCB COO LBCL without these features. Routine performance of more comprehensive pathologic analysis of tumors may inform the use of polatuzumab based therapy in patients with LBCL.

Double hit lymphoma: contemporary understanding and practices.

Double-hit lymphoma (DHL) is a high-risk subtype of large B-cell lymphoma, defined by concurrent rearrangements MYC and BCL2. The diagnosis is confirmed through histologic and immunophenotypic examination and fluorescence in situ hybridization (FISH) to demonstrate the rearrangements. DHL morphology ranges from DLBCL to high-grade B-cell lymphoma which can resemble Burkitt lymphoma and is almost always germinal center B-cell like (GCB). Prognosis is influenced by elevated lactate dehydrogenase (LDH), advanced stage, and extranodal involvement, among other factors. Treatment outcomes vary, but intensive chemotherapy regimens such as dose-adjusted EPOCH-R have shown the most promising results, though low-risk cases do occur and may do well with less intensive treatments. Recent therapeutic advances such as CAR-T cells and bispecific antibodies offer promise for patients with relapsed/refractory disease. This review synthesizes data from recent literature to provide a comprehensive analysis of the molecular underpinnings, diagnostic criteria, prognostic factors, and therapeutic strategies for DHL.

MicroRNA Expression in Exosome Extracellular Vesicles as Targets for Personalized Medicine in Diffuse Large B Cell Lymphoma Patients with HIV Infection.

Extracellular Vesicles (EVs), more specifically exosomes (xEVs), have been associated with Diffuse Large B-cell Lymphoma (DLBCL). These xEVs contain a variety of biomolecules, such as proteins and nucleic acids (e.g., microRNA, LncRNA, and DNA). The expressions of these vesicles in the setting of Human Immunodeficiency Virus (HIV) have been linked to disease progression. Studies have explored the use of EVs in more practical clinical settings. Several studies have found that biomolecules within xEVs can serve to detect disease progression. The biomolecule content within xEVs is useful in prognostication and has even been associated with mechanisms of resistance for some DLBCL treatment modalities. This review article explores the role of xEV biomolecule content in DLBCL progression in the context of HIV infection and its applied use in practical disease management.

Single-cell sequencing in diffuse large B-cell lymphoma: C1qC is a potential tumor-promoting factor.

BACKGROUND: Complement component 1q (C1q) is central to the classical complement pathway. High C1q expression has been linked to poor prognosis in patients with cancer. However, the precise mechanism via which C1q contributes to diffuse large B-cell lymphoma (DLBCL) is still unknown. We aimed to explore the potential mechanism by which C1qC promoting DLBCL. METHODS: Using multiplex immunohistochemistry (mIHC) to identify immunocyte subgroups associated with prognosis in DLBCL tissues. Constructing a risk prediction model based on immunocytes using least absolute shrinkage and selection operator (LASSO) regression. Single-cell sequencing detects the expression level of C1qC in immunocytes in the DLBCL microenvironment. Using Wb and qPCR to detect markers of M2 macrophages after knocking down C1qC, and exploring the interactions between lymphoma cells and macrophages through co-culture. Analyzing clinical data from DLBCL patients to investigate the clinical significance of C1qC+ M2 macrophages. Lastly, using bioinformatics in conjunction with mIHC to elucidate the potential pro-tumor mechanism of C1qC. RESULTS: First, we found T cell subtypes, neutrophils, and M2 macrophages are associated with prognosis. Subsequently, the risk model identified C1qC as a differential gene relevant to DLBCL prognosis. Furthermore, single-cell sequencing suggested high C1qC expression in M2 macrophages. The expression level of CD163 is significantly lower following siC1qC. Co-culture experiments have shown that M2 macrophages can promote the proliferation of tumor cells and reduce their drug sensitivity. Furthermore, as an independent predictive indicator, high expression of C1qC+ M2 macrophages is associated with poor prognosis in patients. Finally, a positive correlation between increased C1qC expression and immune checkpoints, as well as an increase in the infiltration of regulatory T cells (Tregs) and M2 macrophages. CONCLUSIONS: C1qC offering new insights into pathogenesis and presenting a potential therapeutic target in DLBCL.

Biological Findings and Clinical Outcomes in Patients Treated With R-CHOP Plus High-Dose Methotrexate as First-Line Therapy in Large B-Cell Lymphoma With Testis Involvement.

Primary testicular lymphoma (PTL) is a rare occurrence of diffuse large B-cell lymphoma (DLBCL) that accounts for 1%-2% of all cases. Nodal DLBCL with testis involvement (DLBCL-T) and PTL are associated with poor prognosis, with high incidence of central nervous system relapse. Fifteen patients (median age 60 years) with PTL (n = 5) or DLBCL-T (n = 10) received high-dose methotrexate + R-CHOP. Overall, complete response (CR) rate was 73% and overall response rate 86%. With a 3.9-year median follow-up, 100% of patients with PTL had CR and none relapsed. On the contrary, 55% of DLBCL-T patients achieved CR among which only one was still in remission at the end of follow-up. Molecular parallels between PTL and Primary CNS Lymphoma (PCNSL) suggest shared origins, urging further research for tailored treatments and enhanced understanding of these lymphomas' biology.

Utility of clinical, laboratory, and lymph node MYD88 L265P mutation in risk assessment of diffuse large B-cell lymphoma patients.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma and is characterized by heterogeneity in biology and clinical behavior. Mutations in the myeloid differentiation primary response 88 (MYD88) are found in different lymphoproliferative disorders and are associated with variable clinical and prognostic impact. AIM: To investigate the frequency of MYD88 L265P mutation and its clinical impact in a cohort of Egyptian DLBCL patients. METHODS: FFPE lymph node samples from 87 DLBCL patients (46 males / 41 females; median age, 58 years) were included and analyzed for MYD88 L265P by an allele-specific PCR. RESULTS: MYD88 L265P mutations were found in 52 patients (59.8%) out of 87 DLBCL cases. Patients with L265 mutation were significantly younger than non-mutated patients (p = 0.022). None of the patients with the L265P mutation showed a significant association with the clinical parameters of DLBCL. Interestingly, MYD88 L265 mutated patients were found to be significantly correlated with HCV infection (p = 0.037). The median follow-up time across the entire cohort was 26 months. Univariate analysis showed that overall survival (OS) was affected by gender, LDH level, and CNS-IPI scoring (p = 0.048, 0.008, and 0.046, respectively), while disease-free survival (DFS) was affected by B symptoms and LDH level (p = < 0.000 and 0.02, respectively). However, the MYD88 mutation status and other prognostic factors showed no association with OS or DFS. CONCLUSIONS: Our findings indicate a high frequency of MYD88 L265P mutations in our study population and not associated with prognostic markers or the outcome of the disease.

A Biphasic Presentation of Diffuse Large B-cell Lymphoma Metastasis to the Hypothalamus-pituitary Axis: A Case Report and Literature Review.

The Hypothalamus-Pituitary axis (HPA) is a rare location for metastasis of non-Hodgkin's lymphoma. Lymphomas constitute less than 0.5% of reported HPA metastasis. This case is unique in that, in addition to the noted panhypopituitarism; initial diagnostics demonstrated marked hyponatremia, consistent with syndrome of inappropriate antidiuretic hormone (SIADH), which was subsequently complicated by sudden diabetes insipidus (DI), suggesting hypothalamic/stalk infiltration. Despite low sensitivity, CSF cytology/flow cytometry may serve as a less invasive diagnostic measure. Treatment includes systemic chemotherapy with agents that cross the blood-brain barrier. Surgical resection alone or associated radiotherapy did not show an increase in survival. The prognosis remains poor.

Plasma long non-coding RNAs as biomarkers for bone marrow infiltration and stage in diffuse large B-cell lymphoma.

We aimed to evaluate the expression profiles of five circulating lncRNAs (HOTAIR, MALAT-1, XIST, SNHG15, and H19) in DLBCL patients and explore potential associations between their expression and different clinicopathological features. Diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma (NHL), exhibits marked genetic and clinical heterogeneity, emphasizing the need for improved tools for risk stratification. Long non-coding RNAs (lncRNAs) emerged as regulators in different cellular processes and have been linked to cancer pathogenesis. Real-time quantitative PCR (qRT-PCR) was used to evaluate lncRNA expression in the plasma of 65 newly diagnosed adult DLBCL patients and 30 age-matched controls. HOTAIR expression was significantly elevated in DLBCL patients, while SNHG15 was significantly downregulated. Interestingly, both HOTAIR and SNHG15 demonstrated robust discriminatory power between DLBCL and healthy individuals, achieving area under the curve (AUC) values of 69% and 71%, respectively. H19 expression displayed a significant association with early-stage (stage I) DLBCL. While upregulated HOTAIR was a significant independent predictor of poor prognosis, high SNHG15 expression appeared to have a protective effect on mortality rates. Our findings suggest that circulating lncRNA expression patterns are promising tools as non-invasive biomarkers for diagnosis of DLBCL. Specific lncRNAs, such as HOTAIR, SNHG15, and H19, could offer potential for disease staging and patient prognosis. Long-term follow-up studies are recommended to further elucidate the interplay between these lncRNAs and survival rates, as well as their interactions with other genetic and pathological features of DLBCL.

Neurolymphomatosis mimicking a Guillain-Barré syndrome triggered by COVID-19 vaccination.

Guillain-Barré syndrome (GBS) is an acute disorder of the peripheral nervous system, causing flaccid paralysis, areflexia, and variable sensory involvement. Proximal as well distal muscles of the limbs can be involved, and in most severe and advanced cases progresses to respiratory failure and death. GBS is considered an autoimmune disease, and at the basis of the attack at the peripheral nervous system different mechanisms have been recognized, in particular viral infections or other immune stimulations. Cranial nerve involvement in patients with diffuse large B-cell lymphoma (DLBCL) and primary central nervous system lymphoma are rare conditions that could present with similar clinical features. Here we present a case of a 36-year-old man hospitalized for acute polyradiculoneuritis of the cranial nerves and lumbar roots that arose a 14 days after severe acute respiratory syndrome COVID-19 2 (Sars-CoV-2) vaccination. Most of the main criteria for the diagnosis of GBS were met, including clinical and electrophysiological criteria. Albuminocytologic dissociation and high protein level in cerebrospinal fluid were also found. Therefore, the patient was treated with a cycle of intravenous immunoglobulin (IVIG) with notable improvement of symptoms and gradual recovery of motility. A five months later, following SARS-CoV-2 infection, the patient presented with worsening of neurological symptoms and was readmitted to the hospital. He underwent instrumental tests again and was treated with repeated cycles of IVIG and then with a cycle of plasmapheresis without any improvement. In the following 10 days he developed very serious conditions; he was transferred to intensive care unit and deceased after 6 days. The cause of the neurological syndrome was determined only after autoptic analysis, which revealed the presence of primary peripheral nervous system (PNS) DLBCL. The reported case highlights that GBS-like presentation always requires a careful differential diagnosis, and physicians should also consider the possibility of an occult cancer.

Applying Molecular Modeling to the Design of Innovative, Non-Symmetrical CXCR4 Inhibitors with Potent Anticancer Activity.

The identification of new compounds with potential activity against CXC chemokine receptor type 4 (CXCR4) has been broadly studied, implying several chemical families, particularly AMD3100 derivatives. Molecular modeling has played a pivotal role in the identification of new active compounds. But, has its golden age ended? A virtual library of 450,000 tetraamines of general structure 8 was constructed by using five spacers and 300 diamines, which were obtained from the corresponding commercially available cyclic amines. Diversity selection was performed to guide the virtual screening of the former database and to select the most representative set of compounds. Molecular docking on the CXCR4 crystal structure allowed us to rank the selection and identify those candidate molecules with potential antitumor activity against diffuse large B-cell lymphoma (DLBCL). Among them, compound A{17,18} stood out for being a non-symmetrical structure, synthetically feasible, and with promising activity against DLBCL in in vitro experiments. The focused study of symmetrical-related compounds allowed us to identify potential pre-hits (IC50~20 µM), evidencing that molecular design is still relevant in the development of new CXCR4 inhibitor candidates.

Left ovarian mass revealing multivisceral lymphoma.

Lymphoma encompasses a range of cancers originating in the lymphatic system, categorized into Hodgkin lymphoma and non-Hodgkin lymphoma. Hodgkin lymphoma classically present as nodal disease, whereas non-Hodgkin lymphoma tends to involve extranodal regions. While it can be part of a systemic lymphoma, isolated nodal involvement is not uncommon. Extranodal lymphoma can affect virtually any organ or tissue, with the spleen, liver, gastrointestinal tract, pancreas, abdominal wall, genitourinary tract, adrenal glands, peritoneal cavity, and biliary tract being among the most commonly involved sites, in decreasing order of frequency. We present a case involving a 54-year-old woman presented with left iliac fossa pain. A sonography was performed, which showed left pelvic mass, magnetic resonance imaging showed left ovarian mass with enlargement of the cervix. Computed tomography revealed enlargement of the pancreas and adrenal glands, along with masses in the kidneys associated with extensive pathological lymph node enlargement in the para-aortic and pelvic regions. The patient underwent biopsy of a para-aortic lymph node, which revealed a diffuse large B cell lymphoma.

Circulating tumor DNA in diffuse large B-cell lymphoma: analysis of response assessment, correlation with PET/CT and clone evolution.

INTRODUCTION: Circulating tumor DNA (ctDNA) can be obtained from cell-free DNA (cfDNA) andis a new technique for genotyping, response assessment and prognosis in lymphoma. METHODS: Eighteen patients with samples at diagnosis (ctDNA1), after treatment (ctDNA2) and extracted from diagnostic tissue (FFPE) were evaluated. RESULTS: In all patients, at least one mutation in cfDNA was detected at diagnosis. CREBBP was the most frequent mutated gene (67 %). In 12 of the 15 patients with complete remission, the mutation attributed to the disease found at diagnosis cleared with treatment. A reduction in the ctDNA was observed after treatment in 14 patients, 12 of whom achieved complete remission. Correlations were found between the ctDNA at diagnosis and total metabolic tumor volume (r = 0.51; p-value = 0.014) and total lesion glycolysis 2.5 (r = 0.47; p-value = 0.024) by PET at diagnosis and between ctDNA at diagnosis and radiomic features of the lesions with the largest standardized uptake value. There was a strong inverse correlation between ΔctDNA1 and ΔSUVmax by PET/CT (r = -0.8788; p-value = 0.002). CONCLUSION: Analysis of ctDNA and PET/CT in large B-cell lymphoma are complementary data for evaluating tumor burden and tumor clearance after treatment. Analysis of radiomic data might help to identify tumor characteristics and their changes after treatment.

The future of immunotherapy for diffuse large B-cell lymphoma.

With the introduction of anti-CD19 chimeric antigen receptor (CAR) T-cell (CAR T) therapies, bispecific CD3/CD20 antibodies and anti-CD19 antibodies, immunotherapy continues to transform the treatment of diffuse large B-cell lymphoma (DLBCL). A number of novel immunotherapeutic strategies are under investigation to build upon current clinical benefit and offer further options to those patients who cannot tolerate conventional intensive therapies due to their age and/or state of health. Alongside immunotherapies that leverage the adaptive immune response, natural killer (NK) cell and myeloid cell-engaging therapies can utilize the innate immune system. Monoclonal antibodies engineered for greater recognition by the patient's immune system can enhance antitumor cytotoxic mechanisms mediated by NK cells and macrophages. In addition, CAR technology is extending into NK cells and macrophages and investigational immune checkpoint inhibitors targeting macrophage/myeloid cell checkpoints via the CD47/SIRPα axis are in development. Regimens that engage both innate and adaptive immune responses may help to overcome resistance to current immunotherapies. Furthermore, combinations of immunotherapy and oncogenic pathway inhibitors to reprogram the immunosuppressive tumor microenvironment of DLBCL may also potentiate antitumor responses. As immunotherapy treatment options continue to expand, both in the first-line setting and further lines of therapy, understanding how to harness these immunotherapies and the potential for combination approaches will be important for the development of future DLBCL treatment approaches.

Understanding the Puzzle of Primary Breast Lymphoma: An Experience in a Tertiary Care Center in North India.

Background Breast carcinoma is the most common cause of death in women arising primarily from either epithelial or stromal components. Primary breast lymphoma (PBL) is a less common type of neoplasm arising from the lymphoid tissue and is classified as non-Hodgkin's lymphoma (NHL). PBL is a rare tumor that accounts for less than 1% of total primary malignant neoplasms of the breast. The majority of PBLs are of B-cell origin; the most common histological type is diffuse large B-cell lymphoma (DLBCL) followed by follicular lymphoma (FL) and other T-cell and B-cell lymphomas. Material and methods We conducted this five-year retrospective descriptive PBL study from July 2019 to May 2024 at a tertiary care center in North India. We included 11 cases of diagnosed PBL based on morphology and confirmation by at least one lymphoid differentiation marker, that is, leukocyte common antigen (LCA). We retrieved paraffin-embedded blocks from the archive and conducted routine hematoxylin and eosin (H&E) staining and Leishman's stain. We applied an extended immunohistochemistry (IHC) panel to confirm the microscopic findings. We used the Dako® (Agilent Diagnostics & Genomics Group) antibody with a dilution of 1:100.  Results In this study, patients' mean age was 46.8 years (32 to 84 years). Radiological findings indicated that the tumor was indistinguishable from carcinoma. Microscopic findings showed that cells were medium to large lymphoid cells displaying moderate pleomorphism, centrally placed nuclei, vesicular to coarsely clumped chromatin, and scant cytoplasm. IHC showed one case of T-cell origin (ALCL) and 10 of B-cell origin. Among the B-cell cases, four were DLBCL, four were high-grade NHL likely DLBCL and two were high-grade lymphoma. Conclusion Primary breast lymphoma is a rare tumor that closely resembles breast carcinoma clinically as well as radiologically. This study is an effort to highlight the importance of clinical, radiological, and histopathological parameters as well as immunohistochemical features in confirming diagnosis. We also emphasize a treatment protocol and survival outcome in hopes that this knowledge will provide an understanding of early diagnosis and proper management of disease.

Real-World Analysis of Barriers to Timely Administration of Chimeric Antigen Receptor T Cell (CAR T) Therapy in Diffuse Large B-cell Lymphoma.

The implementation of chimeric antigen receptor T (CAR T) therapy in the real-world setting is hindered by logistical and financial barriers, impacting timely access to this life-saving treatment. Clinical trials have reported the time from leukapheresis to CAR T cell infusion (vein-to-vein time) but not the time from CAR T referral to infusion (decision-to-vein time). Herein, we report the barriers to CAR T therapy in a real-world setting. We evaluated the factors influencing the decision-to-vein time and explored the association with clinical outcomes in patients with relapsed or refractory diffuse large B cell lymphoma (DLBCL) who received CAR T therapy. We conducted a retrospective study of adult patients with relapsed/refractory DLBCL who underwent consultation for CAR T cell therapy at Levine Cancer Institute and Wake Forest Comprehensive Cancer Center and collected information regarding demographic data, referral type, insurance type, CAR T product, and survival outcomes. The effects of variables on decision-to-vein time were analyzed by Fisher's exact test for categorial variables and Wilcoxon rank-sum test for continuous variables. Survival analyses were performed using Kaplan-Meier and Cox Proportional Hazard models. The study included 142 patients who were referred for CAR T of which 99 patients received CAR T. Median decision-to-vein time was 62 days compared to median vein-to-vein time of 32 days. Patients with private insurance took longer to obtain financial clearance compared to patients with government insurance (median 25 versus 9 days, P < .001). Of those with private insurance (n = 63), 35% needed a single-case agreement (SCA) which led to significant delay in receiving financial clearance (median 50.5 versus 19 days, P < .001) and increased decision-to-vein time (median 75 versus 55 days, P < .001) compared to those who did not need SCA. Decision-to-vein time was significantly different among various products, clinical trial being the shortest (median 47 days, n = 9) and non-conforming products being the longest (median 94.5 days, n = 6) (P< .001). Axi-cel had the shortest median decision-to-vein time at 61 days compared to 81 days with tisa-cel and 85 days with liso-cel. Although delays in receiving CAR T therapy did not impact survival, the median overall survival for patients who were referred for CAR T therapy but did not receive it, was significantly lower than those who received CAR T cell therapy (9.0 versus 21.0 months, P < .001). Decision-to-vein time is a major cause of delay in receiving CAR T therapy. SCAs lead to significant increase in decision-to-vein time leading to delays in CAR T therapy in a real-world setting. Patients who were referred for CAR T but are not able to receive it, have inferior survival compared to CAR T recipients. Our findings underscore the significance of addressing administrative hurdles, such as SCAs and insurance approvals, for timely access to CAR T therapy for patients with DLBCL.

NEAT1 and CHROMR lncRNAs: a promising diagnostic tool for diffuse large B-cell lymphoma especially in elderly patients.

Background: Long non-coding (lnc) RNAs have crucial regulatory roles in molecular pathways, and their dysregulation is associated with the pathogenesis of malignancies such as Diffuse large B-cell lymphoma (DLBCL). Therefore, we aimed to study the NEAT1 and CHROMR expression in DLBCL and explore their association with clinicopathological characteristics.Methods & materials: DLBCL and non-tumor lymph node specimens were obtained to assess the expression levels.Results: NEAT1 and CHROMR expressions were significantly increased in DLBCL, and were linked with the age of DLBCL patients (aged >60). NEAT1 and CHROMR overexpression may serve as moderate-to-good diagnostic biomarkers, with NEAT1 and CHROMR exhibiting area under the curve values of 0.781 and 0.831, respectively.

[Box: see text].

FASN contributes to ADM resistance of diffuse large B-cell lymphoma by inhibiting ferroptosis via nf-κB/STAT3/GPX4 axis.

Drug resistance is a critical impediment to efficient therapy of diffuse large B-cell lymphoma (DLBCL) patients. Recent studies have highlighted the association between ferroptosis and drug resistance that has been reported. Fatty acid synthase (FASN) is always related to a poor prognosis. In this study, we investigate the impact of FASN on drug resistance in DLBCL and explore its potential modulation of ferroptosis mechanisms. The clinical correlation of FASN mRNA expression was first analyzed to confirm the role of FASN on drug resistance in DLBCL based on the TCGA database. Next, the impact of FASN on ferroptosis was investigated in vitro and in vivo. Furthermore, a combination of RNA-seq, western blot, luciferase reporter, and ChIP experiments was employed to elucidate the underlying mechanism. The prognosis for patients with DLBCL was worse when FASN was highly expressed, particularly in those undergoing chemotherapy for Adriamycin (ADM). FASN promoted tumor growth and resistance of DLBCL to ADM, both in vitro and in vivo. It is noteworthy that this effect was achieved by inhibiting ferroptosis, since Fer-1 (a ferroptosis inhibitor) treatment significantly recovered the effects of silencing FASN on inhibiting ferroptosis, while Erastin (a ferroptosis inducer) treatment attenuated the impact of overexpressing FASN. Mechanistically, FASN activated NF-κB/STAT3 signaling pathway through phosphorylating the upstream IKKα and IκBα, and the activated STAT3 promoted GPX4 expression by directly binding to GPX4 promoter. FASN inhibits ferroptosis in DLBCL via NF-κB/STAT3/GPX4 signaling pathway, indicating its critical role in mediating ADM resistance of DLBCL.

Decreased PU.1 expression in mature B cells induces lymphomagenesis.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma, accounting for 30% of non-Hodgkin lymphomas. Although comprehensive analysis of genetic abnormalities has led to the classification of lymphomas, the exact mechanism of lymphomagenesis remains elusive. The Ets family transcription factor, PU.1, encoded by Spi1, is essential for the development of myeloid and lymphoid cells. Our previous research illustrated the tumor suppressor function of PU.1 in classical Hodgkin lymphoma and myeloma cells. In the current study, we found that patients with DLBCL exhibited notably reduced PU.1 expression in their lymphoma cells, particularly in the non-germinal center B-cell-like (GCB) subtype. This observation suggests that downregulation of PU.1 may be implicated in DLBCL tumor growth. To further assess PU.1's role in mature B cells in vivo, we generated conditional Spi1 knockout mice using Cγ1-Cre mice. Remarkably, 13 of the 23 knockout mice (56%) showed splenomegaly, lymphadenopathy, or masses, with some having histologically confirmed B-cell lymphomas. In contrast, no wild-type mice developed B-cell lymphoma. In addition, RNA-seq analysis of lymphoma cells from Cγ1-Cre Spi1F/F mice showed high frequency of each monoclonal CDR3 sequence, indicating that these lymphoma cells were monoclonal tumor cells. When these B lymphoma cells were transplanted into immunodeficient recipient mice, all mice died within 3 weeks. Lentiviral-transduced Spi1 rescued 60% of the recipient mice, suggesting that PU.1 has a tumor suppressor function in vivo. Collectively, PU.1 is a tumor suppressor in mature B cells, and decreased PU.1 results in mature B-cell lymphoma development.