Case Of Burkitt's Lymphoma Research Articles

The Evolution of a Hospital-Based Cancer Registry in Northwest Cameroon from 2004 to 2015.

Effective cancer registration is required for the development of cancer management policies, but is often deficient in the developing world. In 2008 cancer registration was set up Banso Baptist Hospital and Mbingo Baptist Hospital in the Northwest region of Cameroon, using the Pediatric Oncology Networked Database (POND). The objective of this study was to analyze the POND registry data for patients with cancer aged 0-15 years for the period 2004-15. A total of 1029 malignancies were recorded in children 0-15 years in the study period. The male-to-female ratio was 1.4:1. The median age at diagnosis was 7.22 years. The most common malignancies were lymphomas followed by nephroblastoma, retinoblastoma, rhabdomyosarcoma and Kaposi sarcoma. There were more Burkitt lymphomas cases between 2004 and 2009 than between 2010 and 2015, while the number of cases rose for other diagnoses like retinoblastoma and nephroblastoma. This report has demonstrated how pediatric oncology registration can be implemented, improved and sustained in a low- and middle-income country setting with limited resources. Using the data, these hospitals can improve their treatment planning and ensure the availability of essential chemotherapy for childhood cancers.

BURKITT LYMPHOMA SECONDARY TO METHOTREXATE USE

SESSION TITLE: Fellows Disorders of the Pleura Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Burkitt lymphoma (BL) is a highly aggressive, rapidly growing B cell non-Hodgkin lymphoma. There are three subtypes that are currently recognized including sporadic, endemic, and immunodeficiency-associated. Most commonly, immunodeficiency-associated BL is seen in HIV-positive patients, transplant recipients and congenital immunodeficiency. We present a case of Burkitt lymphoma in a young patient whose only risk factor was methotrexate use for uveitis. CASE PRESENTATION: 25 year old female with past medical history most significant for hypertension and uveitis. She was diagnosed with uveitis at the age of 6 which had been treated with methotrexate for years. She presented with acute (2 days) shortness of breath. Patient’s shortness of breath began the day prior to admission after having dinner. She denied any sick contacts, fevers, chills or abdominal pain. She is active and works as a school teacher. She denied using any illicit drugs, tobacco, or alcohol. She had no family history of cancer. While in the emergency room, patient had a CT thorax which showed no pulmonary embolism but did show a 4cm right hilar mass and large right pleural effusion. Pulmonary service was consulted and a thoracentesis was performed. After the thoracentesis was performed, a CT abdomen was obtained as malignancy was on the differential for metastatic workup, which showed a 15cm ovarian mass. However the patient did not have any abdominal symptoms. Cytology from the thoracentesis was consistent with B-cell lymphoma. Patient eventually underwent an endobronchial ultrasound and fine-needle aspiration and core biopsy of R4 lymph node which were consistent with Burkitt Lymphoma. Bone marrow biopsy also showed EBV+ Burkitt lymphoma with presence of chromosomal translocation of t(8;14). DISCUSSION: Burkitt Lymphoma (BL) presentation is quite heterogenous. BL is Endemic in Africa with majority of cases presenting as facial or jaw bone tumors. Sporadic BL is seen commonly in younger Caucasian patients and presents as abdominal disease with ascites. Immunodeficiency-associated BL often effects lymph nodes, bone marrow and CNS. There are some publication of methotrexate-associated lymphoproliferative disorders and even fewer publications describing methotrexate-associate B cell lymphomas. Here we present a young, African American patient who presented with only shortness of breath and no abdominal symptoms. She fits under sporadic and immunodeficiency-associated category of BL. Given her only risk factor of methotrexate use, she is a rare case of methotrexate causing immunodeficiency and subsequent Burkitt Lymphoma. Interestingly, her treatment of lymphoma included the use of intrathecal methotrexate. CONCLUSIONS: Burkitt Lymphoma presents in very heterogenous ways. Methotrexate is known to cause lymphoproliferative disorders but we present a rare case of methotrexate being associated with Burkitt Lymphoma. Reference #1: Methotrexate-induced B-cell lymphoma. Journal of the American Academy of Dermatology, Volume 79, Issue 3, AB192 Reference #2: Kalisz K, Alessandrino F, Beck R, et al. An update on Burkitt lymphoma: a review of pathogenesis and multimodality imaging assessment of disease presentation, treatment response, and recurrence. Insights Imaging. 2019;10(1):56. Published 2019 May 21. doi:10.1186/s13244-019-0733-7 DISCLOSURES: No relevant relationships by Amish Shah, source=Web Response No relevant relationships by Girish Trikha, source=Web Response

Small İntestine İntussusception Accompanying With Bilateral Adrenal Mass In A 11 Years Old Child With Burkitt Lymphoma

The Gastrointestinal system is one of the most common places for extranodal Non-Hodgkin lymphomas. On the other hand, Non-Hodgkin lymphomas have been seen less in the small intestine. We present here a rare condition in the literature which is a case of bilateral adrenal mass and Burkitt lymphoma with small intestine origin. Eleven years old male patient applied to pediatric emergency service with acute abdomen. In the abdominal USG examination intussusception and bilateral adrenal mass had seen. In a surgical operation, five lesions were seen in the small intestine. Partial small intestine resection was performed. In the pathological examination of the resection material Burkitt Lymphoma with the origin of the small intestine diagnosed to the patient. Prognosis of NHL with the origin of the small intestine, adrenal mass and come with an acute abdomen depends on the histological type and grade. He was started on NHL - BFM95 chemotherapy and had a good clinical response and he was remained in complete remission for two months after completion of chemotherapy. Bilateral adrenal mass remains a rare form of Burkitt lymphoma and care must be taken in ruling out other causes of bilateral adrenal masses.

Aggressive B‐cell lymphomas with a primary bone marrow presentation

Aggressive B-cell lymphomas present as a heterogeneous spectrum of disease. A primary diagnosis in the bone marrow (BM) may be challenging in terms of diagnostic classification and clinical handling, owing to limited architectural information. Aggressive B-cell lymphomas can be subdivided into entities that typically present primarily in the BM, and cases with BM involvement in which the bulk of disease is present in other organs. One main topic at the 2018 BM workshop of the European Association of Haematopathology/Society of Hematopathology was therefore aggressive B-cell lymphomas with a primary BM presentation. The spectrum of cases submitted to this topic gave a good overview of commonly encountered problems, as well as unusual manifestations, and highlighted areas of imprecise disease definitions and diagnostic grey zones. The categories submitted to the workshop included cases of Burkitt lymphoma (BL) with unusual features, high-grade B-cell lymphomas (HG-BCLs) with and without so-called double/triple-hit, and diffuse large B-cell lymphomas (DLBCLs) with a primary BM presentation. Areas of difficulties included the morphological boundaries of HG-BCL not otherwise specified, cases with MYC and bcl-2 or bcl-6 translocations and terminal deoxynucleotidyl transferase (TdT) expression, which were categorised as B-cell lymphoblastic leukaemia/lymphoma if most cells showed TdT positivity, and the clinicopathological overlap between intravascular large B-cell lymphoma, CD5-positive DLBCL, and DLBCL with primary presentations in the BM, spleen, and liver. This review summarises our understanding of the main aggressive B-cell lymphoma categories with a common primary BM presentation and potential problem areas, and makes suggestions for the immunophenotypic and genetic work-up, illustrated by the interesting and challenging cases submitted to the workshop.

Immune landscape in Burkitt lymphoma reveals M2-macrophage polarization and correlation between PD-L1 expression and non-canonical EBV latency program

BackgroundThe Tumor Microenviroment (TME) is a complex milieu that is increasingly recognized as a key factor in multiple stages of disease progression and responses to therapy as well as escape from immune surveillance. However, the precise contribution of specific immune effector and immune suppressor components of the TME in Burkitt lymphoma (BL) remains poorly understood.MethodsIn this paper, we applied the computational algorithm CIBERSORT to Gene Expression Profiling (GEP) datasets of 40 BL samples to draw a map of immune and stromal components of TME. Furthermore, by multiple immunohistochemistry (IHC) and multispectral immunofluorescence (IF), we investigated the TME of additional series of 40 BL cases to evaluate the role of the Programmed Death-1 and Programmed Death Ligand-1 (PD-1/PD-L1) immune checkpoint axis.ResultsOur results indicate that M2 polarized macrophages are the most prominent TME component in BL. In addition, we investigated the correlation between PD-L1 and latent membrane protein-2A (LMP2A) expression on tumour cells, highlighting a subgroup of BL cases characterized by a non-canonical latency program of EBV with an activated PD-L1 pathway.ConclusionIn conclusion, our study analysed the TME in BL and identified a tolerogenic immune signature highlighting new potential therapeutic targets.

Improving Augmented Human Intelligence to Distinguish Burkitt Lymphoma From Diffuse Large B-Cell Lymphoma Cases.

To assess and improve the assistive role of a deep, densely connected convolutional neural network (CNN) to hematopathologists in differentiating histologic images of Burkitt lymphoma (BL) from diffuse large B-cell lymphoma (DLBCL). A total of 10,818 images from BL (n = 34) and DLBCL (n = 36) cases were used to either train or apply different CNNs. Networks differed by number of training images and pixels of images, absence of color, pixel and staining augmentation, and depth of the network, among other parameters. Cases classified correctly were 17 of 18 (94%), nine with 100% of images correct by the best performing network showing a receiver operating characteristic curve analysis area under the curve 0.92 for both DLBCL and BL. The best performing CNN used all available training images, two random subcrops per image of 448 × 448 pixels, random H&E staining image augmentation, random horizontal flipping of images, random alteration of contrast, reduction on validation error plateau of 15 epochs, block size of six, batch size of 32, and depth of 22. Other networks and decreasing training images had poorer performance. CNNs are promising augmented human intelligence tools for differentiating a subset of BL and DLBCL cases.

Expression of p-AKT and p-mTOR in pediatric Burkitt lymphoma and their correlation with prognosis

Objective: To evaluate the expression of p-AKT and p-mTOR, the key proteins in PI3K/AKT/mTOR pathway in pediatric Burkitt lymphoma (BL), and to investigate the clinical and prognostic significance. Methods: Fifty-eight cases of pediatric BL and thirty cases of reactive hyperplastic lymphadenitis (RH) were collected at Children's Hospital of Fudan University from September 2011 to July 2018. Paraffin sections of tissues were immune stained for p-AKT and p-mTOR, and the expression was assessed and correlated with the clinical features and prognosis. Results: A total of 58 cases were diagnosed and 6 cases lost the follow-up. Of the remaining 52 BL patients including 43 males and 9 females, the median age was 5 years (range: 2 to 14 years). Regarding to the correlation between the two biomarkers, Spearman test showed that p-mTOR was positively associated with the expression of p-AKT (r=0.759, P<0.001). Of all BL patients, the positive rates of p-AKT and p-mTOR were 62.1% (36/58) and 60.3%(35/58) respectively, both significantly higher than control group (P=0.011, P=0.035 respectively). The presence of p-AKT was significantly associated with higher lactate dehydrogenase (LDH≥573 IU/L) level in patients of the disease (P=0.006), while p-mTOR was increased both in the higher LDH and lower ratio of albumin to globulin (A/G) group (P=0.006, P=0.034 respectively). Expression of p-AKT and p-mTOR did not show any statistical correlation with sex, age, St.jude stage, tumor size, B-symptom present or not, number of extra-nodal sites or international prognostic index (IPI) (P>0.05). Fifty-two patients had a median follow-up of 40 months (range: 5-87 months). Univariate analysis showed that p-AKT expression was significant in predicting both inferior OS (5-year estimate, 72.7% vs. 94.7%, χ(2)=4.123, P=0.042) and PFS (5-year estimate, 66.7% vs. 94.7%, χ(2)=5.822, P=0.016). The 5-year OS rate was 71.0% (22/31) for the p-mTOR positive cohort of patients compared to 95.2% (17/21) for p-mTOR negative group (χ(2)=4.881, P=0.027); however, there was no statistical significance in 5-year PFS rate (P>0.05). Especially, the 5-year OS and PFS rate of p-AKT/p-mTOR double-positive group were significantly lower than negative control group (including absence of single p-AKT or p-mTOR expression, and absence of both) (OS: 69.0% vs. 95.7%, χ(2)=6.285, P=0.012; PFS: 65.5% vs. 91.3%, χ(2)=5.405, P=0.020). The results of multivariate COX proportional risk regression analysis indicated that p-AKT/p-mTOR double-positive, higher LDH and IPI score 3-5 were independent prognostic factors for both OS and PFS, and the bulky tumor (>10 cm) for PFS of pediatric BL. Conclusion: The expression of p-AKT and p-mTOR may be a potential reference for diagnosis and the independent prognostic indicators of pediatric BL.

Comprehensive Molecular Profiling for Relapsed/Refractory Pediatric Burkitt Lymphomas—Retrospective Analysis of Three Real-Life Clinical Cases—Addressing Issues on Randomization and Customization at the Bedside

In order to identify reasons for treatment failures when using targeted therapies, we have analyzed the comprehensive molecular profiles of three relapsed, poor-prognosis Burkitt lymphoma cases. All three cases had resembling clinical presentation and histology and all three patients relapsed, but their outcomes differed significantly. The samples of their tumor tissue were analyzed using whole-exome sequencing, gene expression profiling, phosphoproteomic assays, and single-cell phosphoflow cytometry. These results explain different treatment responses of the three histologically identical but molecularly different tumors. Our findings support a personalized approach for patient with high risk, refractory, and rare diseases and may contribute to personalized and customized treatment efforts for patients with limited treatment options like relapsed/refractory Burkitt lymphoma.SummaryThe main aim of this study is to analyze three relapsed Burkitt lymphoma patients using a comprehensive molecular profiling, in order to explain their different outcomes and to propose a biomarker-based targeted treatment. In cases 1 and 3, the tumor tissue and the host were analyzed prospectively and appropriate target for the treatment was successfully implemented; however, in case 2, analyses become available only retrospectively and his empirically based rescue treatment did not hit the right target of his disease.

The Association between the Comprehensive Epstein-Barr Virus Serologic Profile and Endemic Burkitt Lymphoma.

The discovery of Epstein-Barr virus (EBV) in Burkitt lymphoma tumors represented the first link between a virus and cancer in humans, but the underlying role of this virus in endemic Burkitt lymphoma remains unclear. Nearly all children in Burkitt lymphoma-endemic areas are seropositive for EBV, but only a small percentage develop disease. Variation in EBV-directed immunity could be an explanatory cofactor. We examined serum from 150 Burkitt lymphoma cases and 150 controls using a protein microarray that measured IgG and IgA antibodies against 202 sequences across the entire EBV proteome. Variation in the EBV-directed antibody repertoire between Burkitt lymphoma cases and controls was assessed using unpaired t tests. ORs quantifying the association between anti-EBV IgG response tertiles and Burkitt lymphoma status were adjusted for age, sex, and study year. Thirty-three anti-EBV IgG responses were elevated in Burkitt lymphoma cases compared with controls (P ≤ 0.0003). Burkitt lymphoma-associated IgG elevations were strongest for EBV proteins involved in viral replication and antiapoptotic signaling. Specifically, we observed ORs ≥4 for BMRF1 (early antigen), BBLF1 (tegument protein), BHRF1 (Bcl-2 homolog), BZLF1 (Zebra), BILF2 (glycoprotein), BLRF2 [viral capsid antigen (VCA)p23], BDLF4, and BFRF3 (VCAp18). Adjustment for malaria exposure and inheritance of the sickle cell variant did not alter associations. Our data suggest that the anti-EBV serologic profile in patients with Burkitt lymphoma is altered, with strong elevations in 33 of the measured anti-EBV IgG antibodies relative to disease-free children. The Burkitt lymphoma-specific signature included EBV-based markers relevant for viral replication and antiapoptotic activity, providing clues for future Burkitt lymphoma pathogenesis research.

A case of HIV-associated Burkitt lymphoma diagnosed via cytology of cerebrospinal fluid collected at autopsy

A case of HIV-associated Burkitt lymphoma diagnosed via cytology of cerebrospinal fluid collected at autopsy

Epstein barr virus IgG and EBER-1 in Burkitt's lymphoma children at a referral hospital in western Kenya.

Burkitt's lymphoma (BL) is a frequent childhood B cell non-Hodgkin's lymphoma (NHL) in equatorial Africa associated with infections. Chronic Epstein Barr virus (EBV) infections can lead to host immune stimulation that may trigger genetic translocation(s), neoplastic transformation and proliferation of B cells. We determined EBV immunoglobulin G (IgG) in sera from participants and EBER-1 in tumour sections in confirmed BL cases at Moi Teaching and Referral Hospital (MTRH). A cross sectional study of children with clinical and histology diagnosis of NHL from whom BL status were confirmed by immunohistochemistry (IHC) was carried out. Epstein Barr virus IgG in sera was determine using Enzyme-linked immunosorbant assay, IHC for EBER-1 and MYC protein in tumour sections. Demographic and clinical information were obtained from questionnaires and hospital files respectively. Ninety three percent of sera were EBV IgG positive of which 31.7% were confirmed as BL. All jaw BL tumours and 86.7% of BL tumours carried EBER-1 antigen. Odds ratio of EBER-1 positive was 1.39, 95% CI: 0.16-12.19 in BL tumours regardless of age or gender. EBV infection among the study participants may be associated with BL, however, EBER-1 and MYC negative in BL tumours suggest alternative BL pathogenesis or variant.

Molecular characteristics of terminal deoxynucleotidyl transferase negative precursor B‐cell phenotype Burkitt leukemia with IGH‐MYC rearrangement

Precursor B cell phenotype Burkitt lymphoma/leukemia with IGH-MYC is a rare subtype of Burkitt lymphoma (BL). BL and B lymphoblastic leukemia/lymphoma (B-ALL/LBL) differ as regards treatment and the distinction between these two entities is crucial. Patients demonstrating a terminal deoxynucleotidyl transferase (TdT)-positive precursor B cell phenotype with IGH-MYC rearrangement have been reported to be molecularly distinct from BL and closer to B-ALL/LBL. We investigated the molecular characteristics of two cases of a rare but distinct TdT-negative precursor B cell phenotype BL. Both patients showed FAB L3 morphology with IGH-MYC translocation, but had precursor B cell immunophenotypes including dim to moderate expression of CD45 and absence of BCL6, CD20, monoclonal kappa, and lambda light chain expression. To characterize the molecular features, we performed exome sequencing and analyzed the breakpoint junction of the IGH-MYC rearrangement. We detected KMT2D mutations in both cases, a rarely acquired chromatin modifying gene mutation in BL. The breakpoint analysis revealed that the IGH-MYC rearrangement occurred due to an aberrant VDJ recombination in one case. The treatment protocols differed, including high-grade lymphoma treatment and standard B-ALL treatment. Complete remission was achieved in the patient who received B-ALL treatment. The degree of resemblance of BL and B-ALL differed between two cases, but the molecular pathogenesis and manifesting features of both TdT-negative precursor B cell phenotype BL case were distinct from classic BL, which indicates the need for a better understanding of this uncommon entity that does not fit in current diagnostic and classification categories.

Molecular switch from MYC to MYCN expression in MYC protein negative Burkitt lymphoma cases

MYC is the most altered oncogene in human cancer, and belongs to a large family of genes, including MYCN and MYCL. Recently, while assessing the degree of correlation between MYC gene rearrangement and MYC protein expression in aggressive B-cell lymphomas, we observed few Burkitt lymphoma (BL) cases lacking MYC protein expression despite the translocation involving the MYC gene. Therefore, in the present study we aimed to better characterize such cases. Our results identified two sub-groups of MYC protein negative BL: one lacking detectable MYC protein expression but presenting MYCN mRNA and protein expression; the second characterized by the lack of both MYC and MYCN proteins but showing MYC mRNA. Interestingly, the two sub-groups presented a different pattern of SNVs affecting MYC gene family members that may induce the switch from MYC to MYCN. Particulary, MYCN-expressing cases show MYCN SNVs at interaction interface that stabilize the protein associated with loss-of-function of MYC. This finding highlights MYCN as a reliable diagnostic marker in such cases. Nevertheless, due to the overlapping clinic, morphology and immunohistochemistry (apart for MYC versus MYCN protein expression) of both sub-groups, the described cases represent bona fide BL according to the current criteria of the World Health Organization.

The Evaluation and Treatment (Tx) of Burkitt Lymphoma (BL) in the Modern Era: Real World (RW) Outcomes and Prognostication across 26 US Cancer Centers (CC)

The Evaluation and Treatment (Tx) of Burkitt Lymphoma (BL) in the Modern Era: Real World (RW) Outcomes and Prognostication across 26 US Cancer Centers (CC)

Improving Augmented Human Intelligence to Distinguish Burkitt Lymphoma From Diffuse Large B-Cell Lymphoma Cases

Abstract Introduction Our objective is to improve the assistive role of a deep, densely connected convolutional neural network (CNN) to hematopathologists in differentiating histologic images of Burkitt lymphoma (BL) from diffuse large B-cell lymphoma (DLBCL). We hypothesized that for the majority of cases, a CNN would accurately differentiate BL from DLBCL and attempted to identify design and input variables to improve performance. Methods and Materials In total, 3608 images of BL were collected from 18 cases and 2,071 images of DLBCL were collected from 20 cases using Aperio Image Scope (Leica Biosystems, Buffalo Grove, IL). Cases were randomized into training and unknowns, and three separate CNNs were trained and applied to unknown images. Networks differed by either the size in pixels of the images (network 1 used 32 × 32 while networks 2 and 3 used 224 × 224) or absence of color (in network 2). Decreased numbers of training images were used to evaluate network 3. Results Network 3 performed the best with 17 of 19 (89%) cases classified correctly, 10 with 100% of images correct. Overall, network 3 had 88% accuracy, 80% precision, 81% recall, and an F1 score of 0.81. Receiver operating characteristic (ROC) curve analysis showed an area under the curve (AUC) of 0.89 for DLBCL and 0.88 for BL. Networks 1 and 2 performed more poorly with F1 scores of 0.63 and 0.39, respectively. Decreasing training images by one-half and one-fourth resulted in decreased F1 scores of 0.63 and 0.60, respectively. Conclusions CNNs are promising augmented human intelligence tools for differentiating DLBCL from BL cases and potentially could contribute to improved workflow in the laboratory. More training images, larger image size, and color significantly improved performance of the CNN because of the added information available to the network. More research is under way to optimize the performance of CNNs’ lymphoma application.

A review of five cases of Burkitt lymphoma associated with intestinal intussusception: A consideration of the initial treatment

A review of five cases of Burkitt lymphoma associated with intestinal intussusception: A consideration of the initial treatment

CHARACTERIZING KI67 ANTIBODY STAINING FOR NON-HODGKIN'S LYMPHOMA USING VISIBLE AND NEAR-INFRARED HYPERSPECTRAL IMAGING TECHNIQUES

Objective To assess the model of quantitation of the Ki67 index by employing visible and infrared (Vis-NIR) hyperspectral imaging (HSI) in Non-Hodgkin Lymphomas (NHL) as time and cost-efficient tissue-sparing alternative to standard diagnostic procedures. Material and Methods Ki67 quantitation was done on 19 formalin-fixed paraffin embedded specimens (6 follicular lymphomas (FL); 12 diffuse large B-cell lymphomas (DLBCL) and one Burkitt-lymphoma (BL) by applying classical immunohistochemistry using an automated platform. Subsequent visual quantification of the Ki67 index was comparatively assessed visually and to HSI-based Ki67 index quantification. Results HSI was successfully implemented for analyzing histopathological slides using the IMEC SNAPSCAN camera. There was no significant difference between visual assessment (VA) and HSI (p = 0.257) in FL, while in DLBCL VA resulted in significantly higher Ki67 values than HSI (p = 0.006). Cohens Kappa showed a fair correlation for both FL and DLBCL (Kappa: 0.333 and 0.316, respectively). The case of BL added as a”super-positive” control was consistently measured by both techniques. Conclusion HSI can be used to quantify marker expression using the Ki67 index model. HSI offers additional information on the biochemical composition of tissues, while preserving limited samples. HSI is easy to install enabling optimization of workflows by restricting analysis times at low costs. Future application by automated imaging analyses systems may allow quantitative measurement of more significant areas of tissue samples, diminishing selection bias in commonl visual pathology and improving information on the tissue heterogeneity of a given marker. In summary, HSI is a cost-effective and quick alternative imaging platform when compared to other digital image analysis systems that are significantly more costly and time-consuming.

Expression of platelet parameters and platelet membrane glycoproteins in childhood Burkitt lymphoma

Platelet activation and functional changes in some haematological malignancies have been investigated with little or no known documentation on Burkitt lymphoma (BL). Abnormalities of platelets contribute to either haemorrhage or thrombotic episodes which are life-threatening in patients with BL. Thus, the study aimed at investigating the various platelet indices and platelet membrane glycoproteins in childhood Burkitt lymphoma. Platelet surface membrane glycoproteins (GPIIb/IIIa, P-selectin and GPIV using PAC 1, CD62p and CD36 monoclonal antibodies respectively) and platelet indices (Platelet Count [PLT], Plateletcrite [PCT], Mean Platelet Volume [MPV], Platelet Distribution Width [PDW] and Platelet Large Cell Ratio [P-LCR]) were determined in children with Burkitt lymphoma and healthy children (normal controls) based on flow cytometry and automated blood cell analysis techniques. PLT and PCT were higher in BL cases than in the normal controls with a significant difference in the PLT (P = 0.02). On the contrary, we observed a significant (p < 0.05) lower levels in the other platelet indices (MPV, PDW and P-LCR) in children with BL than the controls. With the exception of CD62 P, the other platelet membrane glycoproteins examined showed a decreased level of expression before and after the addition of an Adenosine -5- diphosphate (ADP) in cases of BL. In addition, PAC-1 was probably known to be associated with Burkitt Lymphoma (Odds Ratio [OR] 6.67, Relative Risk [RR] 3.13, 95% CI 1.06–9.21; p = 0.02). Finally, oral bleeding was observed to be the commonest bleeding episodes associated with childhood BL. Flow cytometry analysis and cell counting techniques of platelet assessment has described the expression of the platelet membrane glycoproteins and parameters in children with Burkitt lymphoma. Thus, children with Burkitt lymphoma tend to show normal to increased level of circulatory platelets but decreased platelet membrane glycoprotein expressions and platelet dysfunction.

MDM4 Is Targeted by 1q Gain and Drives Disease in Burkitt Lymphoma.

Oncogenic MYC activation promotes proliferation in Burkitt lymphoma, but also induces cell-cycle arrest and apoptosis mediated by p53, a tumor suppressor that is mutated in 40% of Burkitt lymphoma cases. To identify molecular dependencies in Burkitt lymphoma, we performed RNAi-based, loss-of-function screening in eight Burkitt lymphoma cell lines and integrated non-Burkitt lymphoma RNAi screens and genetic data. We identified 76 genes essential to Burkitt lymphoma, including genes associated with hematopoietic cell differentiation (FLI1, BCL11A) or B-cell development and activation (PAX5, CDKN1B, JAK2, CARD11) and found a number of context-specific dependencies including oncogene addiction in cell lines with TCF3/ID3 or MYD88 mutation. The strongest genotype-phenotype association was seen for TP53. MDM4, a negative regulator of TP53, was essential in TP53 wild-type (TP53wt) Burkitt lymphoma cell lines. MDM4 knockdown activated p53, induced cell-cycle arrest, and decreased tumor growth in a xenograft model in a p53-dependent manner. Small molecule inhibition of the MDM4-p53 interaction was effective only in TP53wt Burkitt lymphoma cell lines. Moreover, primary TP53wt Burkitt lymphoma samples frequently acquired gains of chromosome 1q, which includes the MDM4 locus, and showed elevated MDM4 mRNA levels. 1q gain was associated with TP53wt across 789 cancer cell lines and MDM4 was essential in the TP53wt-context in 216 cell lines representing 19 cancer entities from the Achilles Project. Our findings highlight the critical role of p53 as a tumor suppressor in Burkitt lymphoma and identify MDM4 as a functional target of 1q gain in a wide range of cancers that is therapeutically targetable. SIGNIFICANCE: Targeting MDM4 to alleviate degradation of p53 can be exploited therapeutically across Burkitt lymphoma and other cancers with wild-type p53 harboring 1q gain, the most frequent copy number alteration in cancer.

Two Pathways of p27Kip1 Degradation Are Required for Murine Lymphoma Driven by Myc and EBV Latent Membrane Protein 2A.

Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A), expressed in EBV latency, contributes to Burkitt lymphoma (BL) development in a murine model by acting as a constitutively active B cell receptor (BCR) mimic. Mice expressing both LMP2A and MYC transgenes (LMP2A/λ-MYC) develop tumors significantly faster than mice only expressing MYC (λ-MYC). Previously, we demonstrated the cell cycle inhibitor p27Kip1 is present at significantly lower levels in LMP2A/λ-MYC mice due to increased posttranslational degradation. P27Kip1 degradation can occur in the cytoplasm following phosphorylation on serine 10 (S10) or in the nucleus via the SCFSkp2 complex, which depends on Cks1. We previously demonstrated an S10A knock-in of p27Kip1 (p27S10A/S10A) that prevented S10 phosphorylation failed to significantly delay tumor onset in LMP2A/λ-MYC mice. We also previously demonstrated that a Cks1 knockout partially delayed tumor onset in LMP2A/λ-MYC mice, but onset was still significantly faster than that in λ-MYC mice. Here, we have combined both genetic manipulations in what we call p27Super mice. LMP2A/λ-MYC/p27Super mice and λ-MYC/p27Super mice both displayed dramatic delays in tumor onset. Strikingly, tumor development in LMP2A/λ-MYC/p27Super mice was later than that in λ-MYC mice and not significantly different from that in λ-MYC/p27Super mice. The p27Super genotype also normalized G1-S-phase cell cycle progression, spleen size, and splenic architecture in LMP2A/λ-MYC mice. Our results reveal both major pathways of p27Kip1 degradation are required for the accelerated BL development driven by LMP2A in our BL model and that blocking both degradation pathways is sufficient to delay Myc-driven tumor development with or without LMP2A.IMPORTANCE BL is a cancer that primarily affects children. The side effects of chemotherapy highlight the need for better BL treatments. Many BL tumors contain EBV, and our goal is to determine what makes EBV-positive BL different from EBV-negative BL. This may lead to more specific treatments for both types. All cases of BL require overexpression of MYC Mice engineered to express EBV LMP2A along with MYC (LMP2A/λ-MYC mice) develop tumors much more quickly than mice only expressing MYC (λ-MYC mice). Blocking degradation of the cell cycle inhibitor protein p27Kip1 in LMP2A/λ-MYC mice causes tumors to develop later than in λ-MYC mice, showing that p27Kip1 degradation may play a larger role in EBV-positive BL than EBV-negative BL. Furthermore, our studies suggest the cell cycle is an attractive target as a treatment option for LMP2A-positive cancers in humans.