Burkitt lymphoma in Iraqi children: A distinctive form of sporadic disease with high incidence of EBV+ cases and more frequent expression of MUM1/IRF4 protein in cases with head and neck presentation

Presentation of B-cell lymphoma in childhood and adolescence: a systematic review and meta-analysis

BACKGROUND

The diagnosis of B-cell lymphoma, one of the commonest cancers seen in childhood and adolescence, is challenging. There is a crucial need to identify and delineate the prevalence of associated symptoms in order to improve early diagnosis.

AIMS

To identify clinical presentations associated with childhood and adolescent B-cell lymphomas and estimate symptom prevalence.

METHODS

A systematic review of observational studies and meta-analysis of proportions was carried out. Medline and EMBASE were systematically searched, with no language restrictions, from inception to 1st August 2022. Observational studies with at least 10 participants, exploring clinical presentations of any childhood and adolescent lymphoma, were selected. Proportions from each study were inputted to determine the weighted average (pooled) proportion, through random-effects meta-analysis.

RESULTS

Studies reported on symptoms, signs and presentation sites at diagnosis of 12,207 children and adolescents up to the age of 20. Hodgkin's lymphoma most frequently presented with adenopathy in the head-and-neck region (79% [95% CI 58%-91%]), whilst non-Hodgkin's lymphoma presented abdominally (55% [95% CI 43%-68%]). Symptoms associated with lymphoma included cervical lymphadenopathy (48% [95% CI 20%-77%]), peripheral lymphadenopathy (51% [95% CI 37%-66%]), B-symptoms (40% [95% CI 34%-44%]), fever (43% [95% CI 34%-54%]), abdominal mass (46% [95% CI 29%-64%]), weight loss (53% [95% CI 39%-66%]), head-and-neck mass (21% [95% CI 6%-47%]), organomegaly (29% [95% CI 23%-37%]), night sweats (19% [95% CI 10%-32%]), abdominal pain (28% [95% CI 15%-47%]), bone pain (17% [95% CI 10%-28%]) and abnormal neurology (11% [95% CI 3%-28%]).

CONCLUSION

This systematic review and meta-analysis of proportions provides insight into the heterogeneous clinical presentations of B-cell lymphoma in childhood and adolescence and provides estimates of symptom prevalence. This information is likely to increase public and clinical awareness of lymphoma presentations and aid earlier diagnosis. This review further highlights the lack of studies exploring childhood and adolescent lymphoma presentations in primary care, where patients are likely to present at the earliest stages of their disease.

Primary manifestation of HIV-related Burkitt lymphoma in the oral and maxillofacial regions

BACKGROUND

Burkitt lymphoma (BL) is a subtype of non-Hodgkin lymphoma. It is strongly associated with HIV infection and has a highly aggressive clinical course. The involvement of the maxillofacial region in BL has rarely been reported.

CASE DESCRIPTION

A 36-year-old woman with HIV-positive status had painless bilateral swelling of the oral mucosa and middle and lower thirds of the face. Microscopic analysis of the oral lesion revealed an atypical lymphoid infiltrate with a starry sky pattern. The lymphoid cells expressed cluster of differentiation 20, cluster of differentiation 10, B-cell lymphoma 6, and c-Myc; the Ki-67 proliferative index was high. The tumor cells were positive for Epstein-Barr virus. These results led to the diagnosis of HIV-related BL.

PRACTICAL IMPLICATIONS

BL and other immunodeficiency-related lymphoproliferative malignancies may affect the oral and maxillofacial regions and should be included in the differential diagnosis of rapidly expanding swelling in young patients.

Worldwide Prevalence of Epstein-Barr Virus in Patients with Burkitt Lymphoma: A Systematic Review and Meta-Analysis

Burkitt lymphoma (BL) is a form of B-cell malignancy that progresses aggressively and is most often seen in children. While Epstein-Barr virus (EBV) is a double-stranded DNA virus that has been linked to a variety of cancers, it can transform B lymphocytes into immortalized cells, as shown in BL. Therefore, the estimated prevalence of EBV in a population may assist in the prediction of whether this population has a high risk of increased BL cases. This systematic review and meta-analysis aimed to estimate the prevalence of Epstein-Barr virus in patients with Burkitt lymphoma. Using the appropriate keywords, four electronic databases were searched. The quality of the included studies was assessed using the Joanna Briggs Institute's critical appraisal tool. The results were reported as percentages with a 95% confidence interval using a random-effects model (CI). PROSPERO was used to register the protocol (CRD42022372293), and 135 studies were included. The prevalence of Epstein-Barr virus in patients with Burkitt lymphoma was 57.5% (95% CI: 51.5 to 63.4, n = 4837). The sensitivity analyses demonstrated consistent results, and 65.2% of studies were of high quality. Egger's test revealed that there was a significant publication bias. EBV was found in a significantly high proportion of BL patients (more than 50% of BL patients). This study recommends EBV testing as an alternative for predictions and the assessment of the clinical disease status of BL.

IRF4 as an Oncogenic Master Transcription Factor

Simple Summary

Master transcription factors regulate essential developmental processes and cellular maintenance that characterize cell identity. Many of them also serve as oncogenes when aberrantly expressed or activated. IRF4 is one of prime examples of oncogenic master transcription factors that has been implicated in various mature lymphoid neoplasms. IRF4 forms unique regulatory circuits and induces oncogenic transcription programs through the interactions with upstream pathways and binding partners.

Abstract

IRF4 is a transcription factor in the interferon regulatory factor (IRF) family. Since the discovery of this gene, various research fields including immunology and oncology have highlighted the unique characteristics and the importance of IRF4 in several biological processes that distinguish it from other IRF family members. In normal lymphocyte development and immunity, IRF4 mediates critical immune responses via interactions with upstream signaling pathways, such as the T-cell receptor and B-cell receptor pathways, as well as their binding partners, which are uniquely expressed in each cell type. On the other hand, IRF4 acts as an oncogene in various mature lymphoid neoplasms when abnormally expressed. IRF4 induces several oncogenes, such as MYC, as well as genes that characterize each cell type by utilizing its ability as a master regulator of immunity. IRF4 and its upstream factor NF-κB form a transcriptional regulatory circuit, including feedback and feedforward loops, to maintain the oncogenic transcriptional program in malignant lymphoid cells. In this review article, we provide an overview of the molecular functions of IRF4 in mature lymphoid neoplasms and highlight its upstream and downstream pathways, as well as the regulatory circuits mediated by IRF4.

Lineage- and Stage-specific Oncogenicity of IRF4

Dysregulation of transcription factor genes represents a unique molecular etiology of hematological malignancies. A number of transcription factors that play a role in hematopoietic cell development, lymphocyte activation or their maintenance have been identified as oncogenes or tumor suppressors. Many of them exert oncogenic abilities in a context-dependent manner by governing the key transcriptional program unique to each cell type. IRF4, a member of the interferon regulatory factor (IRF) family, acts as an essential regulator of the immune system and is a prime example of a stage-specific oncogene. The expression and oncogenicity of IRF4 are restricted to mature lymphoid neoplasms, while IRF4 potentially serves as a tumor suppressor in other cellular contexts. This is in marked contrast to its immediate downstream target, MYC, which can cause cancers in a variety of tissues. In this review article, we provide an overview of the roles of IRF4 in the development of the normal immune system and lymphoid neoplasms and discuss the potential mechanisms of lineage- and stage-specific oncogenicity of IRF4.

Epstein-Barr virus and Burkitt's lymphoma. Associations in Iraqi Kurdistan and twenty-two countries assessed in the International Incidence of Childhood Cancer

Background

Burkitt's lymphoma (BL) has worldwide variations in incidence that are related to the age of Epstein-Barr virus (EBV) infection. This study examined the age-specific incidence rate (ASIR) of BL and community EBV seropositivity in Iraqi Kurdistan and compared results with data from countries tabulated in the International Incidence of Childhood Cancer volume 3 (IICC-3).

Methods

The ASIR (95% confidence intervals) of BL in Sulaimani Governorate of Iraqi Kurdistan were calculated for the years 2010–2020. Specimens from 515 outpatients were tested for IgG and IgM antibodies to EBV viral capsid antigen.

Results

In Sulaimani, 84% of BL occurred under 20 years of age, with an ASIR of 6.2 (4.7–7.7) per million children. This ASIR was not significantly different than that of Egypt, Morocco, Israel, Spain, or France. It was slightly higher than the ASIR of the United States, the United Kingdom, and Germany and markedly higher than for Asia and South Africa. In Africa and much of Asia, early childhood EBV exposure predominates, with nearly all children being infected by 5 years of age. In Sulaimani, just over 50% of children were EBV seropositive at 3 years old and 90% seropositivity was reached at 15 years of age. In Europe and North America, seropositivity is commonly delayed until adolescence or young adulthood and adult predominates over childhood BL.

Conclusion

In the Middle East, childhood BL is relatively common and adult BL is rare. In Sulaimani, EBV seropositivity increases progressively throughout childhood and reaches 92% at mid-adolescence. This may reflect the Mid East more widely. We suggest that the high childhood and low adult BL rates may be a regional effect of a pattern of EBV exposure intermediate between early childhood and adolescent and young adult infections.

Comprehensive global collaboration in the care of 1182 pediatric oncology patients over 12 years: The Iraqi-Italian experience

BACKGROUND

Iraq's health care system has gradually declined after several decades of wars, terrorism, and UN economic sanctions. The Oncology Unit at Children's Welfare Teaching Hospital (CWTH) in Baghdad was lacking basic facilities and support. To address this shortcoming, a humanitarian and educational partnership was established between CWTH and Sapienza University of Rome (SUR).

METHODS

We investigated the outcomes of 80 online and 16 onsite educational sessions and 142 teleconsultation sessions from 2006 to 2014. We also determined the outcomes of pathology reviews by SUR of 1216 tissue specimens submitted by CWTH from 2007 until 2019 for second opinions. The primary outcomes were discordance, concordance, and changes among clinical diagnoses and pathology review findings. The measures included the frequency of teleconsultation and tele-education sessions, the topics discussed in these sessions, and the number of pathology samples requiring second opinions.

FINDINGS

A total of 500 cases were discussed via teleconsultations during the study period. The median patient age was 7 years (range, 24 days to 16·4 years), and the cases comprised 79 benign tumors, 299 leukemias, 120 lymphomas, and 97 solid tumors. The teleconsultation sessions yielded 27 diagnostic changes, 123 confirmed diagnoses, and 13 equivocal impacts. The pathology reviews by SUR were concordant for 996 (81·9%) cases, discordant for 186 (15·3%), and inconclusive for 34 (2·8%). The major cause of discordance was inadequate immunohistochemical staining. The percentage of discordance markedly decreased over time (from 40% to 10%). The cause of the improvement is multifactorial: training of two CWTH pathologists at SUR, better immunohistochemical staining, and the ongoing clinical and pathologic telemedicine activities. The partnership yielded 12 publications, six posters, and three oral presentations by CWTH investigators.

INTERPRETATION

The exchange of knowledge and expertise across continental boundaries meaningfully improved the diagnoses and management of pediatric cancer at CWTH.

Burkitt lymphoma of the head and neck: An international collaborative study

BACKGROUND

Burkitt lymphoma (BL) is an aggressive B-cell lymphoma with three variants (endemic, sporadic, and immunodeficiency-associated), presenting with specific epidemiological and clinical features. Burkitt lymphoma affects the head and neck region (BLHN) in approximately 10% of cases. The aim of this study was to undertake a comparative analysis of the clinicopathologic and immunohistochemical (IHC) features of BLHN diagnosed in patients from Africa, Guatemala, and Brazil.

METHODS

Cases diagnosed as BLHN were collected from the files of six oral pathology laboratory services (Brazil, South Africa, and Guatemala) and one Brazilian pediatric oncology hospital from 1986 to 2020. Clinicopathological and IHC data, and Epstein-Barr virus (EBV) status by in situ hybridization data for each case were reviewed and described.

RESULTS

Of the 52 cases, BLHN was predominant in pediatric patients [43 (82.69%)] and males [43 (82.69%)], with a mean age of 11.26 ± 9.68 years (range, 1-39 years). Neck and cervical lymph nodes [14 (26.92%)], and involvement of both maxilla and mandible [8 (15.38%)], were the most common anatomical sites. Clinically, tumor/swelling [40 (31.25%)], cervical lymphadenopathy [14 (10.94%)], pain [12 (9.38%)], and bone destruction [12 (9.38%)] were frequent findings. All cases showed typical morphological characteristics of BL. IHC profiles included positivity for CD20 [52 (100%)], CD10 [38 (79.17%)], Bcl6 [29 (87.88%)], and c-Myc protein [18 (81.82%)]. EBV was positive in 18 cases (62.07%). The Ki-67 index ranged from 90 to 100%.

CONCLUSION

The clinicopathological and EBV profile of BLHN in South African, Guatemalan, and Brazilian patients is similar.

Clinicopathological analysis of oral Burkitt's lymphoma in pediatric patients: A systematic review

The aim of this study was to integrate the available data regarding pediatric Burkitt's lymphoma (BL) of the oral cavity. A systematic review was conducted following PRISMA guidelines, through a specific search strategy. Twenty-nine publications were included in this study, resulting in a total of 144 cases. Oral BL was predominantly found in males (75.7%). The mandible was the most involved site (37.5%), and all cases clinically exhibited a swelling. Presence of EBV was observed in 33.3% of the cases, and 4 cases reported HIV-positive patients (33.3%). Chemotherapy was the leading treatment choice for oral BL (94.9%), and the overall 5-year survival was 54.3%. Regarding the quality assessment of the studies, most (19 studies; 65.5%) were classified as an overall moderate risk of bias. In conclusion, the clinicopathological characteristics of oral BL in the pediatric population comprise the sporadic and intermediate subtypes. Despite its aggressiveness, this malignancy presents a moderate overall survival.

Childhood cancer care in the Middle East, North Africa, and West/Central Asia: A snapshot across five countries from the POEM network

BACKGROUND

The Pediatric Oncology East and Mediterranean (POEM) network, through this report, provides a snapshot view of an expected child's treatment journey in five countries in the region.

METHODS

Pediatric oncologists from cancer centers in Egypt, Lebanon, Iraq, Jordan, and Pakistan provided input on referral pathways, barriers to care, and patient outcomes, based on personal experience and published data. Outcome data were extracted from institutional registries. A literature review of articles and meeting abstracts was conducted, and results summarized.

RESULTS

Countries across the Middle Eastern, North African, and West Asian region face common difficulties relating to the provision of pediatric oncology care. National registries are largely lacking, with unavailability of outcome data. Economic barriers are a common theme, leading to delays in patient diagnosis, and interruptions and abandonment of therapy. Insufficient infrastructure and human resources, high rates of toxic deaths, and lack of common national protocols are common. The establishment of successful fundraising organizations linked to specific cancer hospitals showcase several success stories, enhancing services, improving patient access, and leading to outcomes comparable to those in developed countries. All identified published literature is institution-based and from only one or a few hospitals. Therefore, outcomes at a national level likely differ due to disparate cancer care capabilities.

CONCLUSION

Well-designed national registries are essential for identifying gaps, and clear referral networks are needed to address delays to diagnosis and therapy. National and transversal programs to improve infrastructure, facilitate knowledge transfer, and promote advocacy, are needed to accelerate progress in the region.

Classical Hodgkin's Lymphoma in the Era of Immune Checkpoint Inhibition

The ligation of programmed cell death 1 (PD-1) with programmed cell death ligand PD-L activates the immune checkpoint leading to T-cell dysfunction, exhaustion, and tolerance, especially in Hodgkin lymphoma (HL) where the PD-L/ Janus kinase (Jak) signaling was frequently found altered. Anti-PD-1 or anti-PD-L1 monoclonal antibodies can reverse this immune checkpoint, releasing the brake on T-cell responses. The characterization of the mechanisms regulating both the expression of PD-1 and PD-L and their function(s) in HL is ongoing. We provide in this review the recent findings focused on this aim with special attention on the major research topics, such as adverse events and resistance to PD-1–PD-L1 inhibitor treatment, together with a part about angiogenesis, extracellular vesicles, and microbiome in HL pathogenesis.

Seroepidemiological analysis and literature review of the prevalence of Epstein-Barr virus and herpesvirus infections in pediatric cases with non-Hodgkin lymphoma in Central Europe

BACKGROUND

Epstein-Barr virus (EBV) is linked to a variety of malignancies; most endemic Burkitt lymphoma (BL) harbor EBV, whereas only a subset of the cases of sporadic BL is EBV positive.

PROCEDURE

We retrospectively determined the herpesvirus seroprevalence at the time of diagnosis in pediatric non-Hodgkin lymphoma (NHL) patients enrolled in NHL-BFM (Berlin-Frankfurt-Muenster) studies. We accessed the seroepidemiological data from 1147 patients that became available during 1990-2007. We included the records from patients 6 months to 18 years of age with BL, T-cell lymphoblastic lymphoma (T-LBL), lymphoblastic precursor B-cell lymphoma (pB-LBL), diffuse large B-cell lymphoma (DLBCL), or anaplastic large cell lymphoma (ALCL).

RESULTS

EBV seropositivity was significantly more frequent in patients with BL than in those with T-LBL. EBV was more prevalent in patients younger than 6 years of age and in patients with BL than in those with non-BL or T-LBL. Event-free survival was significantly lower in varicella-zoster-seronegative patients, but there was no indication of an association to complications due to varicella zoster infection. We found no associations between herpes simplex virus, varicella zoster virus, or human cytomegalovirus seroprevalence and the pediatric Central European NHL cases.

CONCLUSION

Early EBV exposure may increase the risk of BL in Central Europe. A higher involvement of EBV in European BL than originally reported appears at least probable. Our data support the thesis that the distinction between endemic and sporadic BL is artificial and should be replaced by the differentiation between EBV-positive and EBV-negative BL.

Follicular dendritic cells display microvesicle-associated LMP1 in reactive germinal centers of EBV+ classic Hodgkin lymphoma

Expression of the latent membrane protein-1 (LMP1) of Epstein-Barr virus (EBV) was investigated in 153 cases of EBV+ classic Hodgkin lymphoma (cHL); 120 cases were pediatric patients (< 14 years of age) from Iraq, and 33 cases were adult patients from Italy. We describe for the first time the presence of LMP1 protein in EBV-encoded RNA (EBER)-negative follicular dendritic cells (FDCs) of reactive germinal centers (GC) associated with EBV+ cHL. Presence of LMP1+ GCs was independent of geographic region and age of patients. Variable numbers of reactive GCs were present in 22.2% of cases (34 of 153), whereas LMP1 staining of FDCs was present in about a third of cases (10 of 34) with reactive GC. Most cases with LMP1+ GC were mixed-cellularity (MC) subtype, but some nodular sclerosis (NS) was also present. GC cells with LMP1+ FDCs were surrounded by numerous EBV-infected cells which were positive for EBER, LMP1, and CD30. Double immunolocalization analysis revealed that LMP1 was associated with CD63, an exosomal marker, and with CD21. The possibility is discussed that peri-follicular EBV-infected cells release LMP1 protein, perhaps through exosomes, and that the protein is then captured by FDCs and is presented to EBER-negative GC B cells.