[Solitary splenic neoplasm as an unusual presentation in an adolescent with sporadic Burkitt lymphoma]. / Neoplasia esplénica solitaria como presentación inusual en una adolescente con linfoma de Burkitt esporádico.

Burkitt lymphoma is a non-Hodgkin B-cell lymphoma with a high prevalence in the pediatric population. Abdominal manifestations are well known in sporadic Burkitt lymphoma and vary from nonspecific symptoms to intestinal obstruction due to intussusception; however, mass-like splenic involvement has been scarcely described. OBJECTIVE: To present a case of a patient with a splenic mass whose histopathological analysis revealed Burkitt lymphoma. CLINICAL CASE: A 13-year-old female patient presented with abdominal pain, progressive weight loss, and fever. Imaging studies showed a splenic mass, intestinal thickening, and ileal intussusception. Histopathological analysis of spleen biopsy revealed Burkitt lymphoma. After the first cycle of chemotherapy (BFM95-NHL protocol), abdominal symptoms resolved; no other signs suggestive of intussusception were observed, as well as a significant reduction of the splenic mass was observed. CONCLUSIONS: Burkitt lymphoma in pediatric patients can present as a well-defined splenic tumor, causing no splenomegaly. In addition, its management does not require surgery since it can be resolved with chemotherapy.

Marrow talaromycosis as the initial presentation in a case of Burkitt lymphoma.

Talaromyces marneffei is a thermally dimorphic fungus which causes opportunistic infections in immunocompromised individuals. The diagnosis of T. marneffei infection rests on the microscopic demonstration of the fungus in the tissues and/or isolation of the fungus from clinical specimens. In this report, we discuss a case involving a 23-year-old man who presented with a history of intermittent fever, cough and constitutional symptoms. Clinically, the patient exhibited pallor, jaundice, generalized seborrhoeic dermatitis, hepatomegaly, and small palpable cervical lymph nodes. A computed tomography (CT) scan of the abdomen showed homogenous hypodense lesions in both liver lobes. HIV screening result was reactive. Microscopic examination of the bone marrow aspirate smear and trephine biopsy identified fungal bodies, and culture of the marrow aspirate confirmed the presence of T. marneffei. Notably, the liver biopsy revealed Burkitt lymphoma alongside fungal bodies. He was treated with intravenous Amphotericin B but ultimately succumbed to the illness due to severe metabolic acidosis and multiorgan failure. This case underscores the importance of presumptive diagnosis through morphological or histological examination of bone marrow samples, as microbiologic culture methods can be time-consuming. Timely diagnosis and aggressive treatment are critical in managing patients with T. marneffei infection.

Obesity increases genomic instability at DNA repeat-mediated endogenous mutation hotspots.

Obesity is associated with increased cancer risk, yet the underlying mechanisms remain elusive. Obesity-associated cancers involve disruptions in metabolic and cellular pathways, which can lead to genomic instability. Repetitive DNA sequences capable of adopting alternative DNA structures (e.g., H-DNA) stimulate mutations and are enriched at mutation hotspots in human cancer genomes. However, it is not known if obesity impacts DNA repeat-mediated endogenous mutation hotspots. We address this gap by measuring mutation frequencies in obese and normal-weight transgenic reporter mice carrying either a control human B-DNA- or an H-DNA-forming sequence (from a translocation hotspot in c-MYC in Burkitt lymphoma). Here, we discover that H-DNA-induced DNA damage and mutations are elevated in a tissue-specific manner, and DNA repair efficiency is reduced in obese mice compared to those on the control diet. These findings elucidate the impact of obesity on cancer-associated endogenous mutation hotspots, providing mechanistic insight into the link between obesity and cancer.

[Clinical features and outcomes of digestive tract perforation in pediatric mature B-cell non-Hodgkin lymphoma].

To summarize the clinical features and prognosis of pediatric mature B-cell non-Hodgkin lymphoma (mB-NHL) with digestive tract perforation. The clinical manifestations, laboratory and imaging examinations, treatment and outcomes of mB-NHL children complicated with digestive tract perforation admitted to Beijing Children's Hospital of Capital Medical University from January 2016 to June 2023 were retrospectively analyzed. A total of 12 patients were included, with 11 males and 1 female, aged 0.8-16.0 (7.5±5.4) years. Among them, there were 10 cases of Burkitt lymphoma, 1 case of high-grade B-cell lymphoma (HGBL) and 1 case of diffuse large B-cell lymphoma (DLBCL), respectively. Intestinal involvement was involved in all cases, with St.Jude staging ranging from stage Ⅲ to Ⅳ. Eleven cases had large abdominal mass. In 7 cases, abdominal X-ray examination showed free gas under the diaphragm. Eleven cases experienced digestive tract perforation after chemotherapy, and the time of perforation after initiation of chemotherapy was 2.0-111.0 (41.2±33.6) days. The most common site of perforation was ileum (6 cases), followed by gastric wall (2 cases), jejunum (1 case), colon (1 case) and appendix (1 case). Eight patients underwent surgery, and the time between surgery and re-chemotherapy was 7.0-45.0 (17.6±12.0) days. One case with perforation before chemotherapy died after giving up treatment. The remaining 11 cases received conservative treatment or surgical intervention, followed by regular chemotherapy after symptom and infection control. The follow-up time was 6.0-82.0 (45.0±26.1) months, and all survived.

Retrospective analysis of pediatric patients with Burkitt lymphoma treated in Tanzania following the implementation of the 2016 National Treatment Guidelines: Poor outcomes to current standard-of-care therapy.

BACKGROUND: Despite the excellent outcomes achieved in the treatment of pediatric Burkitt lymphoma (BL) in high-income countries (HICs), outcomes remain poor in low- and middle-income countries (LMICs). Efforts to improve BL outcomes in Tanzania included the creation of National Treatment Guidelines in 2016. However, disease outcomes in Tanzania following the creation of these guidelines have not been reported to date. PROCEDURE: Historical records from 2016 to 2021 for patients 0-18 years of age with a diagnosis of BL and seen at Bugando Medical Centre (BMC), in Mwanza, Tanzania, were curated into an electronic database and analyzed descriptively. Patients in this cohort were treated per the Tanzanian National Treatment Guidelines, which include six cycles of cyclophosphamide, vincristine, and methotrexate (COM) chemotherapy with intrathecal methotrexate and cytarabine. RESULTS: In total, 92 BL patients' records were eligible for analysis. Patients in this cohort were most commonly Murphy stage II (28%) or stage III (34%). Nearly all, 91%, met International Network for Cancer Treatment and Research (INCTR) high-risk criteria at presentation. Forty-two percent of patients did not receive a biopsy and were treated with a presumed diagnosis of BL alone. A 1-year event-free survival of 29.6% (95% confidence interval [CI]: 20.3%-39.5%) and a 1-year overall survival of 38.5% (95% CI: 28%-48.9%) were observed. A high rate of treatment abandonment (34%) was also observed. CONCLUSION: In a historical cohort of pediatric patients with BL treated per the 2016 Tanzanian National Treatment Guidelines, we observed poor outcomes and a high rate of abandonment. These outcomes appear inferior to those achieved in the INCTR clinical trial that informed the guidelines' creation, and highlights the importance of "real-world" outcomes data in LMICs. These data reinforce the idea that continued clinical research and capacity building efforts are necessary to improve BL outcomes in LMICs.

Plasma metabolites in childhood Burkitt lymphoma cases and cancer-free controls in Uganda.

INTRODUCTION: Burkitt lymphoma (BL) is an aggressive non-Hodgkin lymphoma associated with Plasmodium falciparum and Epstein-Barr virus, both of which affect metabolic pathways. The metabolomic patterns of BL is unknown. MATERIALS AND METHODS: We measured 627 metabolites in pre-chemotherapy treatment plasma samples from 25 male children (6-11 years) with BL and 25 cancer-free area- and age-frequency-matched male controls from the Epidemiology of Burkitt Lymphoma in East African Children and Minors study in Uganda using liquid chromatography-tandem mass spectrometry. Unconditional, age-adjusted logistic regression analysis was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) for the BL association with 1-standard deviation increase in the log-metabolite concentration, adjusting for multiple comparisons using false discovery rate (FDR) thresholds and Bonferroni correction. RESULTS: Compared to controls, levels for 42 metabolite concentrations differed in BL cases (FDR < 0.001), including triacylglyceride (18:0_38:6), alpha-aminobutyric acid (AABA), ceramide (d18:1/20:0), phosphatidylcholine ae C40:6 and phosphatidylcholine C38:6 as the top signals associated with BL (ORs = 6.9 to 14.7, P < 2.4✕10- 4). Two metabolites (triacylglyceride (18:0_38:6) and AABA) selected using stepwise logistic regression discriminated BL cases from controls with an area under the curve of 0.97 (95% CI: 0.94, 1.00). CONCLUSION: Our findings warrant further examination of plasma metabolites as potential biomarkers for BL risk/diagnosis.

Targeted eradication of EBV-positive cancer cells by CRISPR/dCas9-mediated EBV reactivation in combination with ganciclovir.

Epstein-Barr virus (EBV) is a ubiquitous human tumor virus that establishes lifelong, persistent infections in B cells. The presence of EBV in cancer cells presents an opportunity to target these cells by reactivating the virus from latency. In this study, we developed a novel approach for EBV reactivation termed clustered regularly interspaced short palindromic repeats (CRISPR)/dCas9-mediated EBV reactivation (CMER) strategy. Using modified CRISPR-associated protein 9 (dCas9) fused with VP64, we designed 10 single guide RNAs (sgRNAs) to target and activate the EBV immediate-early gene promoter. In Akata Burkitt lymphoma cells, 9 out of 10 CMER sgRNAs effectively reactivated EBV. Among these, CMER sgRNA-5 triggered robust reactivation across various cell types, including lymphoma, gastric cancer, and nasopharyngeal carcinoma cells. Importantly, the combination of CMER and ganciclovir selectively eliminated EBV-positive cells, regardless of their cell origin. These findings indicate that targeted virus reactivation by CMER, combined with nucleoside analog therapy, holds promise for EBV-associated cancer treatment. IMPORTANCE: This study explores a novel strategy called clustered regularly interspaced short palindromic repeats (CRISPR)/dCas9-mediated Epstein-Barr virus (EBV) reactivation (CMER) to reactivate the Epstein-Barr virus in cancer cells. EBV is associated with various cancers, and reactivating EBV from latency offers a potential therapeutic strategy. We utilized an enzymatically inactive CRISPR-associated protein 9 (dCas9) fused with VP64 and designed 10 single guide RNAs to target the EBV immediate-early gene promoter. Nine of these sgRNAs effectively reactivated EBV in Burkitt lymphoma cells, with CMER sgRNA-5 demonstrating strong reactivation across different cancer cell types. Combining CMER with ganciclovir selectively eliminated EBV-positive cells, showing promise for EBV-associated cancer treatment.

Tumor microenvironment of Burkitt lymphoma: different immune signatures with different clinical behavior.

ABSTRACT: Burkitt lymphoma (BL) is characterized by a tumor microenvironment (TME) in which macrophages represent the main component, determining a distinct histological appearance known as "starry sky" pattern. However, in some instances, BL may exhibit a granulomatous reaction that has been previously linked to favorable prognosis and spontaneous regression. The aim of our study was to deeply characterize the immune landscape of 7 cases of Epstein-Barr virus-positive (EBV+) BL with granulomatous reaction compared with 8 cases of EBV+ BL and 8 EBV-negative (EBV-) BL, both with typical starry sky pattern, by Gene expression profiling performed on the NanoString nCounter platform. Subsequently, the data were validated using multiplex and combined immunostaining. Based on unsupervised clustering of differentially expressed genes, BL samples formed 3 distinct clusters differentially enriched in BL with a diffuse granulomatous reaction (cluster 1), EBV+ BL with typical starry sky pattern (cluster 2), EBV- BL with typical "starry sky" (cluster 3). We observed variations in the immune response signature among BL with granulomatous reaction and BL with typical "starry sky," both EBV+ and EBV-. The TME signature in BL with diffuse granulomatous reaction showed a proinflammatory response, whereas BLs with "starry sky" were characterized by upregulation of M2 polarization and protumor response. Moreover, the analysis of additional signatures revealed an upregulation of the dark zone signature and epigenetic signature in BL with a typical starry sky. Tumor-associated macrophages and epigenetic regulators may be promising targets for additional therapies for BL lymphoma, opening novel immunotherapeutic strategies.

Ciwujianoside E inhibits Burkitt lymphoma cell proliferation and invasion by blocking ENO1-plasminogen interaction and TGF-ß1 activation.

Burkitt's lymphoma (BL) is a rare and highly aggressive B-cell non-Hodgkin lymphoma. Although the outcomes of patients with BL have greatly improved, options for patients with relapsed and refractory BL are limited. Therefore, there is an urgent need to improve BL therapeutics and to develop novel drugs with reduced toxicity. In this study, we demonstrated that enolase 1 (ENO1) is a potential novel drug target for BL treatment. We determined that ENO1 was aberrantly upregulated in BL, which was closely related to its invasiveness and poor clinical outcomes. Furthermore, using RNA interference, we demonstrated that ENO1 depletion significantly inhibited cell proliferation and invasion both in vitro and in vivo. Mechanistically, we established that ENO1 knockdown suppressed the PI3K-AKT and epithelial-mesenchymal transition (EMT) signaling pathways by reducing plasminogen (PLG) recruitment, plasmin (PL) generation, and TGF-ß1 activation. Addition of activated TGF-ß1 protein to the culture medium of shENO1 cells reversed the inhibitory effects on cell proliferation and invasion, as well as those on the PI3K-AKT and EMT signaling pathways. Notably, our research led to the discovery of a novel ENO1-PLG interaction inhibitor, Ciwujianoside E (L-06). L-06 effectively disrupts the interaction between ENO1 and PLG, consequently reducing PL generation and suppressing TGF-ß1 activation. In both in vitro and in vivo experiments, L-06 exerted impressive antitumor effects. In summary, our study elucidated the critical role of ENO1 in BL cell proliferation and invasion and introduced a novel ENO1 inhibitor, which holds promise for improving the treatment of patients with BL in the future.

MicroRNA-focused CRISPR/Cas9 screen identifies miR-142 as a key regulator of Epstein-Barr virus reactivation.

Reactivation from latency plays a significant role in maintaining persistent lifelong Epstein-Barr virus (EBV) infection. Mechanisms governing successful activation and progression of the EBV lytic phase are not fully understood. EBV expresses multiple viral microRNAs (miRNAs) and manipulates several cellular miRNAs to support viral infection. To gain insight into the host miRNAs regulating transitions from EBV latency into the lytic stage, we conducted a CRISPR/Cas9-based screen in EBV+ Burkitt lymphoma (BL) cells using anti-Ig antibodies to crosslink the B cell receptor (BCR) and induce reactivation. Using a gRNA library against >1500 annotated human miRNAs, we identified miR-142 as a key regulator of EBV reactivation. Genetic ablation of miR-142 enhanced levels of immediate early and early lytic gene products in infected BL cells. Ago2-PAR-CLIP experiments with reactivated cells revealed miR-142 targets related to Erk/MAPK signaling, including components directly downstream of the B cell receptor (BCR). Consistent with these findings, disruption of miR-142 enhanced SOS1 levels and Mek phosphorylation in response to surface Ig cross-linking. Effects could be rescued by inhibitors of Mek (cobimetinib) or Raf (dabrafenib). Taken together, these results show that miR-142 functionally regulates SOS1/Ras/Raf/Mek/Erk signaling initiated through the BCR and consequently, restricts EBV entry into the lytic cycle.

The F-box E3 ligase protein FBXO11 regulates EBNA3C-associated degradation of BCL6.

Most mature B-cell malignancies originate from the malignant transformation of germinal center (GC) B cells. The GC reaction appears to have a role in malignant transformation, in which a major player of the GC reaction is BCL6, a key regulator of this process. We now demonstrate that BCL6 protein levels were dramatically decreased in Epstein-Barr virus (EBV)-positive lymphoblastoid cell lines and Burkitt's lymphoma cell lines. Notably, BCL6 degradation was significantly enhanced in the presence of both EBNA3C and FBXO11. Furthermore, the amino-terminal domain of EBNA3C, which contains residues 50-100, interacts directly with FBXO11. The expression of EBNA3C and FBXO11 resulted in a significant induction of cell proliferation. Furthermore, BCL6 protein expression levels were regulated by EBNA3C via the Skp Cullin Fbox (SCF)FBXO11 complex, which mediated its ubiquitylation, and knockdown of FBXO11 suppressed the transformation of lymphoblastoid cell lines. These data provide new insights into the function of EBNA3C in B-cell transformation during GC reaction and raise the possibility of developing new targeted therapies against EBV-associated cancers. IMPORTANCE: The novel revelation in our study involves the suppression of BCL6 expression by the essential Epstein-Barr virus (EBV) antigen EBNA3C, shedding new light on our current comprehension of how EBV contributes to lymphomagenesis by impeding the germinal center reaction. It is crucial to note that while several EBV latent proteins are expressed in infected cells, the collaborative mechanisms among these proteins in regulating B-cell development or inducing B-cell lymphoma require additional investigation. Nonetheless, our findings carry significance for the development of emerging strategies aimed at addressing EBV-associated cancers.

An Unexpected Lymphoma: A Rare Case of Primary Gastric Burkitt's Lymphoma.

Primary gastric Burkitt's lymphoma is an aggressive non-Hodgkin's lymphoma that has been rarely reported in the literature. The majority of primary gastric lymphomas are diffuse large B-cell lymphomas and mucosa-associated lymphoid tissue (MALT) lymphomas. Patients with primary gastric Burkitt's lymphoma can present with abdominal pain, hematemesis, melena, perforation, and obstruction. Diagnosis is made with a combination of clinical, radiological, and pathological findings. Treatment data are limited due to the limited cases reported. We present a case of a 47-year-old female who presented with diffuse abdominal pain, melena, and coffee-ground emesis that was diagnosed with primary gastric Burkitt's lymphoma following biopsies taken from a gastric ulcerated mass found on upper endoscopy.

Sodium arsenite and arsenic trioxide differently affect the oxidative stress of lymphoblastoid cells: An intricate crosstalk between mitochondria, autophagy and cell death.

Although the toxicity of arsenic depends on its chemical forms, few studies have taken into account the ambiguous phenomenon that sodium arsenite (NaAsO2) acts as a potent carcinogen while arsenic trioxide (ATO, As2O3) serves as an effective therapeutic agent in lymphoma, suggesting that NaAsO2 and As2O3 may act via paradoxical ways to either promote or inhibit cancer pathogenesis. Here, we compared the cellular response of the two arsenical compounds, NaAsO2 and As2O3, on the Burkitt lymphoma cell model, the Epstein Barr Virus (EBV)-positive P3HR1 cells. Using flow cytometry and biochemistry analyses, we showed that a NaAsO2 treatment induces P3HR1 cell death, combined with drastic drops in ΔΨm, NAD(P)H and ATP levels. In contrast, As2O3-treated cells resist to cell death, with a moderate reduction of ΔΨm, NAD(P)H and ATP. While both compounds block cells in G2/M and affect their protein carbonylation and lipid peroxidation, As2O3 induces a milder increase in superoxide anions and H2O2 than NaAsO2, associated to a milder inhibition of antioxidant defenses. By electron microscopy, RT-qPCR and image cytometry analyses, we showed that As2O3-treated cells display an overall autophagic response, combined with mitophagy and an unfolded protein response, characteristics that were not observed following a NaAsO2 treatment. As previous works showed that As2O3 reactivates EBV in P3HR1 cells, we treated the EBV- Ramos-1 cells and showed that autophagy was not induced in these EBV- cells upon As2O3 treatment suggesting that the boost of autophagy observed in As2O3-treated P3HR1 cells could be due to the presence of EBV in these cells. Overall, our results suggest that As2O3 is an autophagic inducer which action is enhanced when EBV is present in the cells, in contrast to NaAsO2, which induces cell death. That's why As2O3 is combined with other chemicals, as all-trans retinoic acid, to better target cancer cells in therapeutic treatments.

Molecular targets of glucocorticoids that elucidate their therapeutic efficacy in aggressive lymphomas.

Glucocorticoids have been used for decades to treat lymphomas without an established mechanism of action. Using functional genomic, proteomic, and chemical screens, we discover that glucocorticoids inhibit oncogenic signaling by the B cell receptor (BCR), a recurrent feature of aggressive B cell malignancies, including diffuse large B cell lymphoma and Burkitt lymphoma. Glucocorticoids induce the glucocorticoid receptor (GR) to directly transactivate genes encoding negative regulators of BCR stability (LAPTM5; KLHL14) and the PI3 kinase pathway (INPP5D; DDIT4). GR directly represses transcription of CSK, a kinase that limits the activity of BCR-proximal Src-family kinases. CSK inhibition attenuates the constitutive BCR signaling of lymphomas by hyperactivating Src-family kinases, triggering their ubiquitination and degradation. With the knowledge that glucocorticoids disable oncogenic BCR signaling, they can now be deployed rationally to treat BCR-dependent aggressive lymphomas and used to construct mechanistically sound combination regimens with inhibitors of BTK, PI3 kinase, BCL2, and CSK.

Mosquito Bed Net Use and Burkitt Lymphoma Incidence in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.

Importance: Burkitt lymphoma (BL) is one of the most common childhood cancers in sub-Saharan Africa and is etiologically linked to malaria. However, evidence for an effect of malaria interventions on BL is limited. Objective: To investigate the potential population-level association between large-scale rollout of insecticide-treated bed nets (ITNs) in sub-Saharan Africa in the 2000s and BL incidence. Data Sources: In this systematic review and meta-analysis, a search was conducted in the Embase, Global Health, and Medline databases and in cancer registry publications between January 1, 1990, and February 27, 2023. Study Selection: All epidemiologic studies on BL incidence rates in children and adolescents aged 0 to 15 years in sub-Saharan African countries where malaria is endemic were identified by 2 reviewers blinded to each other's decision. Data Extraction and Synthesis: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. Data were extracted independently by 2 reviewers, and quality was scored based on 3 predefined criteria: data collection, case ascertainment, and calculation of person-time at risk. Main Outcomes and Measures: Incidence rates of BL during childhood and mean ITN use in the population. Data were analyzed using a random-effects negative binomial regression model. Results: Of 2333 studies meeting selection criteria, 23 comprising 66 data points on BL incidence were included based on 5226 BL cases from locations with large-scale ITN use in 17 countries. Rates of BL were 44% (95% CI, 12%-64%) lower in the period after ITN introduction compared with before. The adjusted pooled incidence rates of BL were 1.36 (95% CI, 0.88-2.10) and 0.76 (95% CI, 0.50-1.16) per 100 000 person-years before and after introduction of ITNs, respectively. After adjusting for potential confounders, a 1-percentage point increase in mean ITN use in the population in the 10 years before BL data collection was associated with a 2% (95% CI, 1%-4%) reduction in BL incidence. Conclusions and Relevance: In this systematic review and meta-analysis, large-scale rollout of ITNs in the 2000s was associated with a reduction in BL burden among children in sub-Saharan Africa. Although published data may not be representative of all incidence rates across sub-Saharan Africa, this study highlights a potential additional benefit of malaria control programs.