Autoantibodies targeting the neuronal antigen metabotropic glutamate receptor 5 (mGluR5) have been identified in patients with Ophelia syndrome, which describes a co-occurrence of paraneoplastic limbic encephalitis and Hodgkin lymphoma (HL). Little data exist regarding frequency and function of mGluR5 in HL and its potential role in causing seropositive paraneoplastic disease. We studied a representative cohort of pediatric HL and NHL patients (n = 57) using immunohistochemistry and fluorescence staining to investigate mGluR5 expression. All lymphoma tissues displayed positive mGluR5 staining, with focus on Hodgkin-Reed-Sternberg (H-RS) cells. We did not detect any mGluR5 staining in tumor-free lymph nodes, which is consistent with the absence of GRM5 transcripts in RNA-sequencing data from non-malignant B and T cells. The frequent presence in pediatric lymphoma falls in line with reports of mGluR5 expression and associated tumor progression in other malignancies. We tested for correlation with clinical features, focusing on disease progression and neurological symptoms. Low mGluR5 expression in H-RS cells correlated with young patient age (<15 years) and positive histology for EBV infection. Paraneoplastic or neurological symptoms were found exclusively in HL patients. While an impact of mGluR5 on HL severity remains possible, a prognostic value of mGluR5 expression levels requires further investigation.

BACKGROUND: Hodgkin lymphoma (HL) in pediatric populations has a high survival rate but poses risks for long-term morbidities. Although [18F]fluoro‑2‑deoxy‑2‑d‑glucose positron emission tomography ([18F]FDG PET) scans offer potential for improved risk stratification, the definitive prognostic value of quantitative [18F]FDG PET parameters remains unclear for pediatric HL.
METHODS: A single-center, retrospective study included pediatric patients diagnosed with HL between 2016 and 2023 treated according to EuroNet-PHL-C1 and DAL/GPOH-HD protocols. Patients underwent baseline and interim PET/CT scans after two chemotherapy cycles. Event-free survival (EFS) was the primary endpoint, Deauville score was the secondary endpoint. Quantitative [18F]FDG PET parameters included SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) that were evaluated using two segmentation methods (SUV 2.5, 41% SUVmax). Survival outcomes were assessed using Cox regression analysis.
RESULTS: A total of 115 patients (50 males, median age 14.2 years) were studied, with a median follow-up period of 35 months. During this period, 16 cases (13.9%) of relapse or progression were noted. Baseline and interim MTV 2.5, MTV 41%, TLG 2.5, and TLG 41%, along with interim SUVmax, were significantly associated with worse EFS and correlated with post-treatment Deauville scores. In multivariable analysis, interim MTV 2.5 > 0 ml (adj. hazard ratio, HR: 3.89, p = 0.009) and interim TLG 41% ≥ 30 g (adj. HR: 7.98, p = 0.006) were independent risk factors for EFS.
CONCLUSIONS: Baseline and interim [18F]FDG PET parameters can serve as significant prognostic indicators for EFS and treatment response in pediatric HL. These quantitative measures could enhance individualized, risk-adapted treatment strategies for children and adolescents with HL.

Classical pediatric Hodgkin Lymphoma (HL) is a rare malignancy. Therapeutic regimens for its management may be optimized by establishing treatment response early on. The aim of this study was to identify plasma protein biomarkers enabling the prediction of relapse in pediatric/adolescent HL patients treated under the pediatric EuroNet-PHL-C2 trial. We used untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics at the time of diagnosis—before any therapy—as semiquantitative method to profile plasma proteins specifically associated with relapse in 42 children with nodular sclerosing HL. In both the exploratory and the validation cohorts, six proteins (apolipoprotein E, C4b-binding protein α chain, clusterin, fibrinogen γ chain, prothrombin, and vitronectin) were more abundant in the plasma of patients whose HL relapsed (|fold change| ≥ 1.2, p < 0.05, Student’s t-test). Predicting protein function with the Gene Ontology classification model, the proteins were included in four biological processes (p < 0.01). Using immunoblotting and Luminex assays, we validated two of these candidate biomarkers—C4b-binding protein α chain and clusterin—linked to innate immune response function (GO:0045087). This study identified C4b-binding protein α chain and clusterin as candidate early plasma biomarkers of HL relapse, and important for the purpose of shedding light on the molecular scenario associated with immune response in patients treated under the EuroNet-PHL-C2 trial.

The cannonball pulmonary appearance is hematogenous dissemination of various primary tumors but rarely a Hodgkin\'s lymphoma, a disease that most commonly manifests with lymphadenopathy, often affecting the mediastinum and supraclavicular or cervical lymph nodes. To date, to the best of our knowledge, no case has been reported where the investigation of a cannonball pulmonary appearance led to the diagnosis of Hodgkin\'s lymphoma. Hence, in our case report, we attempt to highlight the uncommon presentation of this disease in a 14-year-old girl who initially presented with dyspnea before her chest x-ray revealed a cannonball pulmonary appearance, which was later linked with Hodgkin\'s lymphoma after performing a biopsy of her axillary node.

OBJECTIVE: ABVD (doxorubicin, bleomycin,vinblastine, and dacarbazine) is not a standard regimen in children due to concerns regarding late effects. However, no studies have evaluated long-term toxicities of ABVD in children.
METHODS: Total 154 pediatric Hodgkin lymphoma (HL) survivors uniformly treated with ABVD were clinically followed up as per institutional protocol. All participants were evaluated for cardiac, pulmonary, and thyroid function abnormalities by multigated acquisition scan (MUGA) scan, spirometry with diffusion capacity of lung for the uptake of carbon monoxide (DLCO), and thyroid profile test, respectively, at a single time point. Predictors of toxicity were also analyzed.
RESULTS: The median duration of follow-up of the cohort was 10.3 years (6.04-16.8). No secondary malignant neoplasm (SMN) or symptomatic cardiac/pulmonary toxicities were detected. Nine patients (5.9%) had left ventricular ejection fraction (LVEF) <55%. Subclinical and overt hypothyroidism were observed in 78 (50.6%) and 16 (10.4%) survivors, respectively. Abnormal spirometry and reduced DLCO was observed in 43.2% and 42.0% survivors, respectively. Receiving neck radiation was significantly associated with thyroid dysfunction (odds ratio [OR] 16.04, p < .001); age ≥10 years predicted reduced DLCO (OR 4.12, p = .001). Sixty-three and 33 patients had one and two late adverse effects, respectively; receiving neck radiation predicted development of multiple late effects (proportional OR 4.72, p < 0.001). Cumulative dose of chemotherapy did not predict toxicity.
CONCLUSIONS: Overall, ABVD appears safe in children at a relatively short follow-up. Long-term safety data are required before it can be adopted for treating pediatric HL patients. Children receiving neck radiation require close follow-up.

BACKGROUND: Hodgkin lymphoma (HL) is lymphoid neoplasm usually affecting lymphatic system; it accounts 3.6% of cancers in Saudi Arabia. Modern treatment protocols had shown particular success rates in overall-survival (OS) and event-free-survival (EFS). In our study, we reviewed the medical records of 80 pediatric and young adolescent patients diagnosed HL from January 2006 to July 2020, treated at tertiary care hospital in Riyadh, Saudi Arabia. Demographic, clinical, and pathological data were explored. First line therapy was ABVD, COG, COPP, R-CHOP, or radiotherapy alone in 53/80 (66.4%), 24/80 (30%), 1/80 (1.2%), 1/80 (1.2%), or 1/80 (1.2%) patients; respectively. Response assessment was done by CT + / - PET scan after first 2 cycles then every 2 cycle and end of therapy. Another assessment was done if any clinical suspicion of recurrence.
RESULTS: Median age 11 (range 3-16) years. Males to females 1.3:1. Seventy-two out of eighty (90%) patients showed first complete remission (CR1) and maintained remission for median 40 (range 7-136) months. Eight out of eighty (10%) patients showed refractory disease. Nineteen patients received salvage therapy (ICE or ESHAP/brentuximab vedotin or gemcitabine/brentuximab vedotin), 14/19 (73.7%) had 2nd complete remission (CR2) for median time 24 (ranged 9-78) months, while 5/19 (26.3%) did not show any response. Five-year OS and EFS were 95% and 75%. Two patients had 2ry malignant neoplasms, one had AML and died, the other had malignant fibrous histocytoma and still alive. None of our patients had fertility problem. Also, they did not experience chronic pulmonary or cardiotoxicity. Classic Hodgkin\'s lymphoma: nodular sclerosis subtype was more prominent (55%) than mixed cellularity subtype (22.5%), which is similar to several European and US studies, lymphocyte rich (11.25%) and lymphocyte depleted (0%), while nodular lymphocyte predominant Hodgkin\'s lymphoma (11.25%).
CONCLUSIONS: Our study provided unique descriptive study of childhood HL, in Saudi Arabia, with valuable insight into the long-term outcome and late toxicity. Our results are comparable to other studies in the Middle East and European countries.

Exosomes and other small extracellular vesicles (EVs) are potential sources of cancer biomarkers. Plasma-derived EVs have not yet been studied in pediatric Hodgkin lymphoma (HL), for which predictive biomarkers of relapse are greatly needed. In this two-part proteomic study, we used two-dimensional difference gel electrophoresis (2D-DIGE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze EV proteins of plasma collected at diagnosis from children with nodular sclerosis HL, relapsed or not. EVs isolated using membrane affinity had radii ranging from 20 to 130 nm and contained the programmed cell death 6-interacting (ALIX) and the tumor susceptibility gene 101 (TSG101) proteins, whereas calnexin (CANX) was not detected. 2D-DIGE identified 16 spots as differentially abundant between non-relapsed and relapsed HL (|fold change| ≥ 1.5, p < 0.05). LC-MS/MS identified these spots as 11 unique proteins, including five more abundant in non-relapsed HL (e.g., complement C4b, C4B; fibrinogen γ chain, FGG) and six more abundant in relapsed HL (e.g., transthyretin, TTR). Shotgun LC-MS/MS on pooled EV proteins from non-relapsed HL identified 161 proteins, including 127 already identified in human exosomes (ExoCarta data). This EV cargo included 89 proteins not yet identified in exosomes from healthy plasma. Functional interrogation by the Database for Annotation, Visualization and Integrated Discovery (DAVID) revealed that the EV proteins participate in platelet degranulation and serine-type endopeptidase activity as the most significant Gene Ontology (GO) biological process and molecular function (p < 0.01).

Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) is a rare clinical entity. To investigate NLPHL clinical course and treatment a survey was performed within Polish Pediatric Leukaemia/Lymphoma Study Group (PPLLSG) participating centers. A questionnaire was sent to all participating centers and analysis of clinical data was performed. From 2010 to 2019, 19 pediatric patients with confirmed NLPHL were registered in Poland. Median age of patients was 12.2 (5.5 - 17.8) years. NLPHL occurred mainly in males (n = 17). Most of the patients (n = 16) had early stage disease - Stage I (n = 6) and stage II (n = 10). Four of the six patients with stage I disease (I A, n = 5; I B, n = 1) underwent complete primary resection. One of these relapsed and was treated with CVP (cyclophosphamide, vinblastine, prednisone) chemotherapy. Two other patients who were not resected completely received CVP chemotherapy and no relapses were observed. Thirteen patients presented with unresectable disease. Of these, eight received three CVP chemotherapy cycles, and five were treated with other chemotherapy regimens. Three relapses were observed and these patients were further treated with chemotherapy and rituximab. One patient underwent autologous stem cell transplantation (auto-SCT). All patients remain alive. Five-year progression-free survival and overall survival for the entire group of patients was 81.6% and 100%, respectively. NLPHL treatment results are consistent with results noted in other countries. Early stage patients have very good outcomes with surgery and observation or low intensity chemotherapy, but this approach may be insufficient in advanced disease.

In the EuroNet Pediatric Hodgkin Lymphoma (EuroNet-PHL) trials, decision on Waldeyer\'s ring (WR) involvement is usually based on clinical assessment, that is, physical examination and/or nasopharyngoscopy. However, clinical assessment only evaluates mucosal surface and is prone to interobserver variability. Modern cross-sectional imaging technology may provide valuable information beyond mucosal surface, which may lead to a more accurate WR staging.
The EuroNet-PHL-C1 trial recruited 2102 patients, of which 1752 underwent central review including reference reading of their cross-sectional imaging data. In 14 of 1752 patients, WR was considered involved according to clinical assessment. In these 14 patients, the WR was re-assessed by applying an imaging-based algorithm considering information from 18 F-fluorodeoxyglucose positron emission tomography, contrast-enhanced computed tomography, and/or magnetic resonance imaging. For verification purposes, the imaging-based algorithm was applied to 100 consecutive patients whose WR was inconspicuous on clinical assessment.
The imaging-based algorithm confirmed WR involvement only in four of the 14 patients. Of the remaining 10 patients, four had retropharyngeal lymph node involvement and six an inconspicuous WR. Applying the imaging-based algorithm to 100 consecutive patients with physiological appearance of their WR on clinical assessment, absence of WR involvement could be confirmed in 99. However, suspicion of WR involvement was raised in one patient.
The imaging-based algorithm was feasible and easily applicable at initial staging of young patients with Hodgkin lymphoma. It increased the accuracy of WR staging, which may contribute to a more individualized treatment in the future.

BACKGROUND: Classic Hodgkin lymphoma (cHL) is a lymphoid malignancy in which the microenvironment, where the neoplastic cells are immersed, contributes to the lymphomagenesis process. Epstein-Barr virus (EBV) presence also influences cHL microenvironment composition and contributes to pathogenesis. An increase in PDL1 expression in tumor cells and at the microenvironment was demonstrated in adult cHL. Therefore, our aim was to assess PD1/PDL1 pathway and EBV influence on this pathway in pediatric cHL, given that in Argentina, our group proved a higher incidence of EBV-associated pediatric lymphoma in children.
METHODS: For that purpose, EBV presence was assessed by in situ hybridization, whereas PD1 and PDL1 expressions were studied by immunohistochemistry. PDL1 genetic alterations were analyzed by FISH, and survival was evaluated for PD1 and PDL1 expressions.
RESULTS: EBV presence demonstrated no influence neither on PD1 expression at the microenvironment nor on PDL1 expression at HRS tumor cells. Unexpectedly, only 38% pediatric cHL displayed PDL1 genetic alterations by FISH, and no difference was observed regarding EBV presence. However, in EBV-related cHL cases, a higher number of PDL1 + cells were detected at the microenvironment.
CONCLUSIONS: Even though a high cytotoxic environment was previously described in EBV-related pediatric cHL, it might be counterbalanced by an immunoregulatory micro-environmental PDL1 + niche. This regulation may render a cytotoxic milieu that unsuccessfully try to eliminate EBV + Hodgkin Reed Sternberg tumor cells in pediatric patients.