Aggressive Mature B-cell Lymphoma Research Articles

Clinical analysis of 18 children with aggressive mature B-cell lymphoma after liver transplantation

Objective: To summarize the clinical characteristics, prognostic factors and treatment outcomes of childhood aggressive mature B-cell lymphoma after liver transplantation. Methods: This retrospective study included 18 children with newly diagnosed aggressive mature B-cell lymphoma after liver transplantation and treated from June 2018 to June 2022 in the Department of Hematology and Oncology of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine. Clinical characteristics, treatment and outcomes of patients at last evaluation were analyzed. Overall survival (OS) and event free survival (EFS) rates were calculated by Kaplan-Meier method and Log-Rank analysis was performed to find factors of poor prognosis. Results: Among all 18 patients, there were 6 males and 12 females, and the age of onset was 40 (35, 54) months. The interval from transplant to tumor diagnosis was 21 (17, 35) months and 5 patients had early onset disease (<1 year since transplant). Seventeen patients had abdominal lesions. Diarrhea, vomiting and abdominal masses were the main clinical manifestations. All patients were Epstein-Barr virus (EBV) related posttransplant lymphoproliferative disorders (PTLD). One patient received individualized therapy due to critical sick at diagnosis, and the remaining 17 patients received CP (cyclophosphamide, methylprednisolone plus rituximab) and/or modified EPOCH (prednisone, etoposide, doxorubicin, vincristine, cyclophosphamide plus rituximab) regimens. Of all 18 patients, 15 cases got complete response, 2 cases got partial response, 1 patient died of severe infection. The 2-year OS and EFS rates of 18 patients were (94±5)% and (83±8)%, respectively. None of age, gender or early onset disease had effect on OS and EFS rates in univariate analysis (all P>0.05). Conclusions: The symptoms of PTLD were atypical. Close surveillance of EBV-DNA for patients after liver transplantation was crucial to early stage PTLD diagnosis. CP or modified EPOCH regimen was efficient for pediatric patients with aggressive mature B cell lymphoma after liver transplantation.

Parotid Burkitt Lymphoma: Case Report

Salivary gland tumors are rare counting only 0.5% of all cancers, only 2% among them are lymphomas. Burkitt lymphomas is an aggressive mature non-Hodgkin B-cell lymphoma characterized by MYC oncogene activation, commonly occurring in nodal sites, however the extranodal sites are mostly seen in immunodeficiency associated Burkitt lymphoma as it is seen in patients with HIV infection. Clinically, the symptoms are related to the acute enlargement of gland due to the fast growing of the tumor and its rapid cells turnover. Diagnostic assessment requires biological investigations as well as cytological, histological and immunohistochemical exams to put out the diagnosis of Burkitt lymphoma. However, imaging is paramount by CT and MRI which finds its interest in its sensibility to characterize salivary gland tumors by the diffusion sequence and the estimation of apparent coefficient of diffusion. That being said, the diagnosis of parotid gland lymphoma is a differential diagnosis of parotid tumor because of its rarity. Our case is about a middle-aged woman suffering from a unilateral parotid swelling, its uncommon evolution pushed the investigations which leads to discovering a HIV infection, a diagnose the patient with a HIV-associated Burkitt lymphoma. We put the light on salivary gland location of this cancer by screening literature on this subject which benefitted from important advances of treatments, offering good outcomes in terms of freedom of event and overall survival.

The Immune Checkpoint Siglec-15 in Promoting Immune Dysregulation in Non-Hodgkin's Lymphomas

Outcomes for patients with relapsed or refractory (r/r) hematologic malignancies remain dismal despite therapeutic advances over the last several years. This is particularly striking in patients with r/r aggressive mature B-cell lymphomas such as Diffuse Large B-cell Lymphoma (DLBCL) and Burkitt's Lymphoma (BL). With use of intensive multiagent chemo-immunotherapy, DLBCL, which accounts for approximately 10-20% of pediatric Non-Hodgkin's Lymphoma (NHL) cases and is the most common subtype in adults, is highly curable with 5-year event free survival &amp;gt;75%. However, approximately 30-40% of adults diagnosed with DLBCL will become refractory to or relapse after first-line treatment. Yet even with intensive salvage regimens, r/r DLBCL remains a clinical challenge. There remains an unmet need to identify specific defects in the immune response, among other pathways, that drive lymphomagenesis that will in turn inform the development of novel therapeutics to improve survival in this population of patients. Siglec-15 (Sig-15), a member of the sialic acid binding immunoglobulin-like lectin family of proteins, has recently been identified as a critical immune suppressor that is highly expressed in human cancers and intra-tumoral myeloid cells. Importantly, recent reports have demonstrated inhibition of Sig-15, has a restorative effect on local anti-tumor immune responses and abrogated tumor progression. While reported in solid malignancies and acute leukemias, a role for Siglec-15 in promoting disease progression in aggressive B-cell lymphomas has not yet been described. We have found higher expression of SIGLEC15 in DLBCL cell lines compared to normal B cells at the RNA level, through analyses of the publicly available ONCOMINE database. This was confirmed at the protein level by western blot demonstrating higher Sig-15 expression in various lymphoma cell lines (RAJI, SUDHL6, OCI-LY10, HBL-1) compared to healthy donor PBMCs. Further, immunohistochemistry evaluating Sig-15 expression was performed on a tumor microarray consisting of 139 cases of DLBCL from adult patients along with validation samples from 15 primary pediatric lymphoma cases (DLBCL, BL and Anaplastic Large Cell Lymphoma (ALCL)). Sig-15 was found to be highly expressed, with histologic scores ranging from weak (1+) to strong (3+) in 124 out of the 139 adult cases (Figure 1A) and in all pediatric lymphoma samples but with distinct staining patterns observed in the aggressive B-cell lymphomas. Specifically, Sig-15 appears to be highly expressed and associated with the cell membrane in most DLBCL and Burkitt's lymphoma. Expression is more variable in ALCL, primarily elevated in the cytoplasm at low levels and/or in macrophages (Figure 1A). There is heterogeneity in Sig-15 expression with preliminary analysis of RNA-seq data from a cohort of 693 DLBCL patient samples demonstrates higher levels in the germinal center B-cell (GCB) versus activated B-cell molecular (ABC) subtype of DLBCL when compared to healthy controls (Kruskal-Wallis, *p = 0.041). Finally, using a well-established murine lymphoma model, A20 cells were stably transduced with control, non-silencing shRNA (shNS) or shRNA against Sig-15 and injected into un-irradiated immune competent (wild type, WT) or immune deficient ( Rag1 -/-) BALB/C mice and monitored for signs of lymphoma development. Knockdown of Sig-15 in A20 cells abrogates disease progression in WT but not immune deficient mice (Log-rank, **p &amp;lt;0.0001, n=10 mice/group), consistent with a role for Sig-15 in immune evasion in lymphoma (Figure 1B). Together, these data implicate Sig-15 as an immune checkpoint that may be inhibited therapeutically to promote an immune response to lymphoma cells.

Differences in Observed Toxicities for Adolescent and Young Adult Patients with Aggressive Mature B-Cell Lymphomas Treated at Adult Versus Pediatric Cancer Center - a Comparative Cohort Study

Introduction: Standard treatment regimens for pediatric and adult patients with mature B-cell lymphomas vary significantly. For adolescent or young adult (AYA) patients, who may be candidates for either pediatric or adult regimens, limited data are available regarding comparative toxicities and efficacy for adult versus pediatric therapies. Methods: A retrospective review was completed for individuals aged 12-39 years at diagnosis with aggressive mature B-cell lymphomas seen between 2011 to 2023 at Ohio State University Comprehensive Care Center (adult cohort) and Nationwide Children's Hospital (pediatric cohort). Diagnoses included diffuse large B cell lymphoma (DLBCL), double hit lymphoma (DHL), Burkitt lymphoma (BL), primary mediastinal B cell lymphoma (PMBCL), grey zone lymphoma (GZL), and unclassifiable high-grade B cell lymphoma (HGBCL). Progression free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method and compared by log-rank test. Differences between adult and pediatric cohort were compared using Fisher's exact test and Chi-squared test. Cox regression model was used to identify prognostic factors for PFS. Results: Among 180 eligible AYA patients, 156 were treated at the adult center and 24 at the pediatric center. The median age was 30 years (median 15 pediatric [range 12-18] and 31 adult [range 21-39; p&amp;lt;0.001]). Other characteristics included male sex in 75% of pediatric vs 65% adult patients (p=0.3), stage 4 disease in 25% vs 47%(p&amp;lt;0.001), CNS involvement in 8.3% vs 5.4% (p=0.6), and LDH &amp;gt;2x upper limit of normal in 21% vs 31% (p=0.2). The overall median follow-up was 4.8 years (4.5 vs 4.8, p=0.7). Adult center histology included DLBCL (95); DHL (9); BL (8); PMBCL (31); GZL (4); and HGBCL (9). Pediatric diagnoses were DLBCL (13); BL (8); PMBCL (2); and HGBCL (1). The most common treatments included R-CHOP (57), R-EPOCH (56), RM-CHOP (20), and R-CODOX-M/R-IVAC (16) at the adult center and CCG5961 (7), ANHL1131 (15), and ANHL0221 (1) protocols at the pediatric center. CCG5961 Group B protocol includes pre-phase, induction, and consolidation phases of COP, COPADM, and CYM. Group C includes the same pre-phase and induction, except for higher doses of MTX, with CYVE consolidation with high-dose MTX and randomization to 1 or 4 cycles of maintenance. ANHL1131 protocol was like CCG5961; major differences include randomization to receive rituximab during induction and consolidation and 2 cycles of maintenance for group C patients. ANHL0221, a PTLD protocol, involves 2 cycles of cyclophosphamide, prednisone, and rituximab followed by 4 cycles of cyclophosphamide and prednisone. A greater incidence of unplanned hospitalization (79% pediatric vs 50% adult, p=0.007), grade 3 mucositis (38% vs 12%, p=0.005), febrile neutropenia (67% vs 44%, p=0.035), and fungal infections (25% vs 3%, p&amp;lt;0.001) were observed for the pediatric cohort (Table 1). Patients in the adult cohort were more likely to receive radiation therapy (26% vs 0%, p=0.004) and experience neuropathy at last follow-up (22% v 0%, p=0.009). Among all patients, other adverse events during follow-up included diagnosis of depression/anxiety (93), heart failure (16), impaired renal function (20), and secondary malignancy (6) (Table 1). For the total population, 2-year PFS was 78% (88% pediatric vs 77% adult, p=0.35), and 2-year OS was 93% (96% vs 92%, p=0.31). For patients with DLBCL or DHL, there was a trend towards improved PFS in the pediatric versus adult cohort (p=0.06, Figure 1), and on univariable analysis a trend towards lower risk for progression with receipt of a more intensive regimen compared with R-CHOP/R-MCHOP (hazard ratio 0.46, 95% confidence interval 0.2-1.1, p=0.07). Conclusions: We observed a higher incidence of short-term adverse effects including severe mucositis, febrile neutropenia, and fungal infection, but lower rates of radiation consolidation and ongoing neuropathy in AYA patients with aggressive mature B-cell lymphoma treated with pediatric versus adult regimens. Relatively higher dose intensity (compared to adult treatments), standard use of CNS prophylaxis, and lower dosage of vinca-alkaloids likely account for the greater incidence of short-term adverse effects and lower rates of neuropathy seen in patients treated at pediatric centers. Further study is needed to evaluate differences in efficacy between treatment approaches in AYA patients with DLBCL/DHL.

A Genomic Approach for High-Grade B Cell Lymphoma with MYC and BCL2 and / or BCL6 Rearrangements: Two Clusters Stood out on Next Generation Sequencing Results

Introduction High-grade B cell lymphomas with double or triple hit rearrangement (HGBL DH/TH), which appeared on the 4th revised edition WHO classification of lymphoid neoplasms, are aggressive mature B-cell lymphomas with high-grade cytology (Burkitt-like, blastoid or DLBCL-like) that have a MYC (8q24) rearrangement in combination with a BCL2 (18q21) and / or a BCL6 (3q27) rearrangement. There are currently no treatment guidelines for this subtype, and the usual immunochemotherapy leads to few complete remissions. While the NGS technology has been used in diffuse large B cell lymphoma, there has been no specific study on additional genetic events which would predict the clinical outcome in HGBL DH/TH. Here, we report our preliminary results using a targeted DNA capture panel approach (NGS) to identify subgroups with different clinical outcomes among HGBL DH/TH. Methods We conducted a retrospective study on 44 patients diagnosed with DH or TH HGBL and treated at Centre Hospitalier Lyon Sud or Centre Léon Bérard starting in 2013. We collected the medical information regarding the treatment, time to response to treatment or relapse, progression free survival, and overall survival. They all benefited from a DNA-targeted NGS analysis covering 54 genes. Results The cohort included 20 females and 24 males, with a median age of 65 (31-87). Among them, 22 patients were MYC/ BCL2 DH (50%), 12 were MYC/ BCL6 DH (27,3%) and 10 were TH (22,7%). Eleven patients had B symptoms (25%). The Ann Arbor stage was high (III-IV) in 97.5%. The WHO Performance Status was low (0-1) for most of the patients (70%). The majority of them presented with an IPI above to 2 (82,5%) and an elevated LDH level (80%). The Ki67 index was above 70% (33/42) in 78,5% of the cases and above 90% (19/42) in nearly half of them. The major finding of the NGS analysis was the identification of 2 groups based on the TP53/ CDKN2A_p14ARF mutational status. The CDKN2A locus encodes for 2 alternative open reading frames leading to 2 unrelated proteins p14ARF and p16INK4A. P14ARF is involved in the regulation of the TP53 pathway whereas p16INK4A is not. We therefor defined 2 groups : the first group included patients with either TP53 or CDKN2A_p14ARF-only alterations (group A, n=10) while the second group had no alteration in these two coding sequences (group B, n=34) although 12 patients had a CDKN2A_p16INK4A loss or mutation affecting both CDKN2A transcripts. Most of TP53 mutations were missense mutations mostly in TP53 DNA-binding domain and 2 cases appeared to be single hit mutations with an allele frequency below 50%. The patient with a p14ARF only mutation had a start codon mutation p.(M1*) with an allele frequency of 96% without CDKN2A copy number loss. The median overall survival (OS) (Figure 1) was 6,2 months for group A, and 55,5 months for group B (p = 0,0076). The median follow-up time was 14 months (7,5 months in the group A, 18 in group B). Only 2 patients in group A survived and are still in complete remission, one was DH BCL6 and the other DH BCL2 Conclusion Our preliminary results indicate a strong negative prognostic impact of either CDKN2A_p14ARF or TP53 gene alterations on the OS of HGBL DH/TH patients. The biological basis for the difference between groups would be in favour of the alteration of the p14ARF-TP53 tumor suppressive pathway as major contributor of chemoresistance. A more detailed analysis is on-going to further identify mutation profiles of double hit and triple hit lymphomas and compare our finding with existing data. Our results confirm the more favourable outcome of DH BCL6 patients (data not shown), which is consistent with the 5 th revised OMS classification that removed that specific entity. Our results also indicate that routine NGS analysis of HGBL DH/TH patients offers new perspectives for patient stratification. Regarding their survival, patients with TP53 pathway alterations should probably not be treated with the standard RCHOP chemo-immunotherapy. Instead, a more intensive immunochemotherapy regimen or novel strategies such as first-line bispecific antibodies or CARTCells might be considered.

Heterogeneous diffuse large B-cell lymphoma: accurate diagnosis as a key to successful therapy. A review

Diffuse large B-cell lymphoma (DLBCL) is the most common variant of non-Hodgkin's lymphoma and accounts for about 1/3 of all non-Hodgkin's lymphomas in Western countries and about 40% of B-cell tumors worldwide. Correct diagnosis of clinically distinct subgroups of aggressive mature B-cell lymphomas is crucial for the choice of adequate treatment. Currently, the identification of DLBCL subtype depends on a combination of morphologic, immunophenotypic, and cytogenetic/molecular features. The classification covers the most common unspecified variant of DLBCL, also referred to as "not otherwise specified" (NOS), and a number of other rare forms. Over the past two decades, DLBCL NOS which accounts for more than 80% of all cases, has been the subject of a growing number of molecular studies that have identified prognostic factors that are being actively introduced into real-world clinical practice. Only the integration of morphological, immunohistochemical and molecular features of DLBCL will lead to the achievement of the long-term goal of curing the majority of patients with minimal or no toxic manifestations with the aid of personalized healthcare.

Subgrouping of Burkitt lymphoma variants by DNA methylation is driven by an EBV‐associated epigenotype

Introduction: Burkitt lymphoma (BL) is an aggressive mature B-cell lymphoma, which traditionally has been separated into three epidemiologic variants: endemic (eBL), sporadic (sBL) and immunodeficiency-associated BL (iBL). This subgrouping is strongly confounded by EBV-infection. Indeed, there is evidence from molecular studies that subtyping of BL based on EBV status might better reflect the pathogenetic heterogeneity than epidemiology. As EBV is known to influence epigenetic regulation, we here aimed at a comparative DNA methylation (DNAme) profiling of BL variants with respect to their geographic origin and EBV status. Methods: We collected DNAme profiles (Infinium HumanMethylation450 and Infinium MethylationEPIC BeadChip) of 116 BL patients (80 sBL: 7 EBV+; 29 eBL: 27 EBV+; 7 iBL: 4 EBV+), 17 BL cell lines and 6 EBV-transformed LCLs. For group determination unsupervised clustering algorithms (K-means, PGMRA, UMAP) were applied. To investigate potential consequences of EBV-associated DNAme we performed a protein-protein interaction network analysis on genes within the EBV-specific DNAme pattern. Moreover, we mined gene expression values from RNAseq in 21 EBV- sBL and 5 germinal-center B-cell populations. Results: Unsupervised clustering algorithms revealed two distinct DNAme phenotypes, which differentiate EBV+ and EBV- BL based on 1,266 CpGs. This separation is accompanied by a characteristic hypermethylation in EBV+ BLs. Additionally, we identified a subgroup of EBV+ BL with a similar DNAme pattern like the LCLs, possibly indicating latency phase differences within EBV+ BLs. Investigation of the EBV-specific DNAme pattern revealed a network with UBC as a key interactor, indicating the potential importance of the ubiquitin-proteasome system (UPS) in EBV-induced lymphomagenesis. Among genes differentially methylated between EBV+ and EBV- BL, 19 genes have been reported as recurrently mutated in BL. All except 3 of these genes are expressed in sBL and germinal-center B-cells. All these genes were significantly hypermethylated within regulatory regions in EBV+ BLs (σ/σmax = 0.4, q ≤ 0.01), including genes with a lower mutational frequency in EBV+ versus EBV- BLs. Conclusion: The findings of this study show the EBV status to be strongly associated with DNAme subgroups in BL, supporting the subtyping of BL variants based on their EBV status rather than their geographic origin. Moreover, the pattern of DNAme in EBV+ BL might suggest epigenetic silencing and deregulated ubiquitination as means alternative to gene mutation to be involved in the pathogenesis of EBV+ BL. Keywords: Aggressive B-cell non-Hodgkin lymphoma, Genomics, Epigenomics, and Other -Omics, Pathology and Classification of Lymphomas No conflicts of interests pertinent to the abstract.

Double-hit and double-expressor primary central nervous system lymphoma: Experience from North India of an infrequent but aggressive variant.

High-grade non-Hodgkin B-cell lymphoma is an aggressive mature B-cell lymphoma that depicts poor treatment response and worse prognosis. The presence of MYC and B-cell lymphoma 2 (BCL2) and/or B-cell lymphoma 6 (BCL6) rearrangements qualifies for triple-hit and double-hit lymphomas (THL/DHL), respectively. We attempted to explore the incidence, distribution, and clinical characteristics of the primary high-grade B-cell lymphoma of the central nervous system (CNS) in our cohort from North India. All the histologically confirmed cases of primary CNS diffuse large B-cell lymphoma (PCNS-DLBCL) over a period of 8 years were included. Cases showing MYC and BCL2 and/or BCL6 expression on immunohistochemistry (IHC) (double- or triple-expressor) were further analyzed by fluorescence in situ hybridization for MYC, BCL2 and /or BCL6 rearrangements. The results were correlated with other clinical and pathological parameters, and outcome. Of total 117 cases of PCNS-DLBCL, there were seven (5.9%) cases of double/triple-expressor lymphomas (DEL/TEL) (six double- and one triple-expressor) with median age of 51 years (age range: 31-77 years) and slight female predilection. All were located supratentorially and were of non-geminal center B-cell phenotype. Only triple-expressor case (MYC+/BCL2+/BCL6+) demonstrated concurrent rearrangements for MYC and BCL6 genes indicating DHL (n = 1, 0.85%), while none of the double-expressors (n = 6) showed MYC, BCL2, or BCL6 rearrangements. The mean overall survival of the DEL/TEL was 48.2 days. DEL/TEL and DHL are uncommon in CNS; mostly located supratentorially and are associated with poor outcome. MYC, BCL2, and BCL6 IHC can be used as an effective screening strategy for ruling out double/ triple-expressor PCNS-DLBCLs.

Primary Mediastinal B-Cell Lymphoma in Children and Young Adults

Primary mediastinal B-cell lymphoma (PMBCL) is a rare but aggressive mature B-cell lymphoma that arises from thymic B cells and most commonly affects adolescents and young adults. PMBCL is now recognized by the WHO as a distinct entity from diffuse large B-cell lymphoma (DLBCL), not otherwise specified, with a unique clinical presentation and distinct morphologic features and molecular alterations. Similar to classic Hodgkin lymphoma, PMBCL tumors are characterized by alterations in the nuclear factor-κB and JAK/STAT pathways. These tumors also exhibit an immune evasion phenotype marked by upregulation of PD-L1 and loss of B2M. Historic data indicates that outcomes for pediatric patients with PMBCL are inferior compared with pediatric patients with DLBCL treated on the same protocols, and there is no current standard approach to initial treatment. Common regimens used for children with PMBCL include multiagent chemotherapy regimens designed for Burkitt lymphoma, such as Lymphomes Malins B (LMB)-based or Berlin-Frankfurt-Münster (BFM)-based chemotherapy ± rituximab. Based on initial data in adults showing excellent outcomes with the use of DA-EPOCH-R regimens, these regimens have also been adopted in pediatrics, although with mixed results. Novel agents are currently being studied in PMBCL with the goal of improving outcomes and reducing reliance on radiation and/or high-dose chemotherapy. Immune checkpoint blockade with PD-1 inhibition is of particular interest given the upregulation of PD-L1 in PMBCL and the known efficacy of these agents in the relapsed setting. Future efforts in PMBCL will also seek to determine the role of FDG-PET in evaluating response to therapy and the role of biomarkers in risk stratification.

Pediatric Aggressive Mature B-Cell Lymphomas, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pediatric Aggressive Mature B-Cell Lymphomas include recommendations for the diagnosis and management of pediatric patients with primary mediastinal large B-cell lymphoma (PMBL) and sporadic variants of Burkitt lymphoma and diffuse large B-cell lymphoma. PMBL is now considered as a distinct entity arising from mature thymic B-cells accounting for 2% of mature B-cell lymphomas in children and adolescents. This discussion section includes the recommendations outlined in the NCCN Guidelines for the diagnosis and management of pediatric patients with PMBL.

Clinical characteristics and treatment outcomes of children and adolescents with aggressive mature B-cell lymphoma: a single-center analysis

BackgroundAggressive mature B-cell non-Hodgkin lymphoma (B-NHL) is the most common non-Hodgkin lymphoma in children. The outcome of chemotherapy for B-NHL has improved over decades.MethodsWe reviewed 82 children and adolescents with B-NHL diagnosed at Asan Medical Center between 1993 and 2020. The D-COMP/COMP (daunomycin–cyclophosphamide, doxorubicin, vincristine, and prednisolone), Pediatric Oncology Group (POG)-9219/9315/9317, R-CHOP/CHOP (rituximab–cyclophosphamide, doxorubicin, vincristine, and prednisolone), and Lymphomes Malins B 89 (LMB89)/LMB96 regimens were administered. In 2018, rituximab was added to the LMB protocol (R-LMB) for advanced-staged Burkitt lymphoma (BL). The patients’ clinical features and treatment outcomes were retrospectively analyzed.ResultsThe most common subtype was BL (61%), followed by diffuse large B-cell lymphoma (DLBCL) (35%). The median age was 7.8 (range, 1.3‒16.4) years, and the most frequently used regimen was French‒American‒British (FAB)/LMB96 (58 patients, 70.7%). The 5-year overall survival (OS) and event-free survival (EFS) rates were 92.5% and 85.7%, respectively. The EFS rates of patients with BL and DLBCL were 90.0% and 79.3%, respectively. Among the FAB/LMB risk groups, group C (85.7%) had a significantly lower 5-year OS (P=0.037). Eleven events occurred (6 relapses, 3 deaths, and 2 secondary malignancies) during the median follow-up of 7.1 (range, 3.7‒118.5) months. Two patients treated with R-LMB had good outcomes without complications.ConclusionVarious treatment regimens have favorable outcomes in pediatric patients with B-NHL. However, further studies are needed to improve survival in high-risk patients. In addition, careful monitoring for acute toxicity or secondary malignancy due to intensive multidrug chemotherapy is required.

Disseminated Double-Hit Lymphoma in a Young Adult

High-grade B-cell lymphoma with MYC and BCL2 and-or BCL6 rearrangements, also called double-hit lymphoma, is an aggressive mature B-cell lymphoma that carries both MYC and BCL2 and/or BCL6 translocations. This can present as a diagnostic challenge since clinical characteristics, morphology and immunophenotype are not accurate indicators of underlying genetic aberrations in this type of lymphoma. We report a case of a 25-year-old male who presented with a one-year history of cough, gradually increasing abdominal girth and jaundice. Definitive diagnosis was made post-mortem with additional ancillary studies using immunohistochemistry staining and fluorescent in-situ hybridization studies.

Assessment of CD52 Expression in “Double-Hit” and “Double-Expressor” Lymphomas: Implications for Clinical Trial Eligibility

High-grade B-cell lymphomas (HGBCL) with MYC and BCL2 and/or BCL6 rearrangements (i.e. “double/triple-hit lymphomas” [DHL/THL]) and the subset of diffuse large B-cell lymphomas (DLBCL) and HGBCL, not otherwise specified (NOS), with MYC and BCL2 protein over-expression (i.e. “double-expressor lymphomas” [DEL]) represent distinct subsets of mature B-cell lymphomas with aggressive clinical course, poor response to conventional chemotherapy and high relapse rates. Compared with other lymphoma subtypes, DHL exhibits a higher frequency of bone marrow (BM) involvement, which in turn is associated with adverse outcome. The BM microenvironment contributes to this negative prognostic impact by promoting chemoresistance through several mechanisms, including the inhibition of antibody-mediated phagocytosis by BM macrophages.The antibody-refractory nature of the BM microenvironment can be temporarily abrogated through the synergistic effects of high-dose cyclophosphamide (CTX), which inhibits secretion of prostaglandin E2 and induces secretion of IL8, TNFα, VEGF, and CCL4 by leukemic cells, resulting in macrophage recruitment, activation and phagocytosis (Pallasch, Cell 2014). The potential of this therapeutic strategy has recently been extended to human-derived xenografts taken from patients with relapsed/refractory DHL (Lossos, Blood 2016 [Abstract]). The humanized monoclonal antibody alemtuzumab (Campath) targets CD52, a GPI-linked glycoprotein frequently expressed by mature lymphocytes. The success of this agent in the proof-of-principle studies referenced above has provided inspiration for a new phase I clinical trial investigating the use of alemtuzumab and low-dose CTX for the treatment of DHL/THL and DEL (ID: NCT03132584).Previous studies have shown significant heterogeneity in CD52 expression by several of the more aggressive mature B-cell lymphomas (e.g. DLBCL, Burkitt lymphoma), with 25% of cases exhibiting negligible expression by immunohistochemistry (IHC) (Rodig, Clin Cancer Res 2006). As such studies predated our current conception of DHL/THL and DEL, the prevalence of CD52 expression within these newer diagnostic categories has remained speculative. To eliminate this knowledge gap and provide decision support for clinical trial enrollment, we assessed the frequency, intensity and uniformity of CD52 expression within 98 cases of DHL/THL and DEL. Our study included 35 DHL (25 with MYC and BCL2 rearrangements, 10 with MYC and BCL6 rearrangements), 5 THL (with MYC, BCL2 and BCL6 rearrangements), 7 HGBCL, NOS, with double-expressor phenotype, and 51 DLBCL, NOS, with double-expressor phenotype (17 of GCB origin, 34 of ABC origin).The majority of DHL/THL and DEL exhibited convincing cytoplasmic and/or membranous CD52 expression (75% in both groups). There was no significant difference in CD52 intensity (scored from 0-3) or predominant staining pattern (cytoplasmic vs. membranous) between DHL/THL and DEL, however DHL/THL were more likely to show uniform (vs. variable) staining [OR = 4.8; P = 0.0026]. Consistent with their predilection for BM, DHL were more likely to be derived from BM biopsies than DEL [OR = 12.1; P = 0.022], however the frequency of CD52 expression within BM specimens was not significantly different than those from other bodily locations. Assigned morphologic group (blastoid vs. DLBCL vs. DLBCL/BL) and the quantitative results of additional IHC studies (BCL2, MYC, Ki67) were similarly non-predictive of CD52 expression status. Within DHL, the presence of BCL2 versus BCL6 translocation had no bearing on CD52 expression, although there was a trend towards increased CD52 expression in the presence of BCL2 translocation [OR = 3.45; P = 0.099]. Among DLBCL with double-expressor phenotype, the Hans cell-of-origin classification (GCB vs. ABC) had no apparent impact on CD52 expression.In summary, our results indicate that CD52 is expressed by the majority of DHL/THL and DEL, suggesting that alemtuzumab-based therapy may be appropriate for most patients. Target validation must be performed on a case-by-case basis, however, as CD52 expression is not readily predicted by histomorphologic, immunophenotypic or cytogenetic findings. DisclosuresLaCasce:Forty Seven: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Seattle Genetics: Consultancy, Research Funding.

Pediatric Aggressive Mature B-Cell Lymphomas, Version 2.2020, NCCN Clinical Practice Guidelines in Oncology.

Pediatric aggressive mature B-cell lymphomas are the most common types of non-Hodgkin lymphoma in children, and they include Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). These diseases are highly aggressive but curable, the treatment is complex, and patients may have many complicated supportive care issues. The NCCN Guidelines for Pediatric Aggressive Mature B-Cell Lymphomas provide guidance regarding pathology and diagnosis, staging, initial treatment, disease reassessment, surveillance, therapy for relapsed/refractory disease, and supportive care for clinicians who treat sporadic pediatric BL and DLBCL.

Integrative genomic analysis focused on cell cycle genes for MYC-driven aggressive mature B-cell lymphoma.

MYC is a transcriptional factor that regulates growth and proliferation through cell cycle pathways. MYC alterations, in particular MYC rearrangements, are important in assessing the prognosis of aggressive B-cell lymphoma. In this study, we focused on the impact of nine major cell cycle genes for MYC-driven aggressive mature B-cell lymphoma and analyzed the mutational status using targeted next generation sequencing. Our 40 cases of aggressive mature B-cell lymphomas included 5 Burkitt lymphomas, 17 high-grade B-cell lymphomas and 18 diffuse large B-cell lymphomas with MYC breaks in 100%, 88% and 11%, respectively. Our data allowed a molecular classification into four categories partially independent from the histopathological diagnosis but correlating with the Ki-67 labelling index: (I) harboring TP53 and CDKN2A mutations, being highly proliferative, (II) with MYC rearrangement associated with MYC and/or ID3 mutations, being highly proliferative, (III) with MYC rearrangement combined with additional molecular changes, being highly proliferative, and (IV) with a diverse pattern of molecular alterations, being less proliferative. Taken together, we found that mutations of TP53, CDKN2A, MYC and ID3 are associated with highly proliferative B-cell lymphomas that could profit from novel therapeutic strategies.

Primary Chest Wall MYC/BCL6 Double-hit Lymphoma with t (3;7) (q27;p12) and t (8;14) (q24;q32) Translocations

Primary chest wall lymphoma is rare and typically associated with chronic pleural inflammation. Double-hit lymphoma (DHL), which is defined as aggressive mature B-cell lymphoma with MYC and BCL2 or BCL6 rearrangements, is a highly aggressive malignancy that tends to have extranodal involvement and is resistant to standard immunochemotherapy. We herein report a 55-year-old man with no history of chronic pleural inflammation, diagnosed with primary chest wall DHL with MYC/BCL6 rearrangement, and harboring a unique BCL6 translocation, t(3;7)(q27;p12). After six courses of intensive chemotherapy, he has achieved complete remission. To our knowledge, this is the first case report of primary chest wall DHL.

Successful Treatment of Aggressive Mature B-cell Lymphoma Mimicking Immune Thrombocytopenic Purpura

A 55-year-old woman suffered from hemorrhagic tendency. She had severe thrombocytopenia without any hematological or coagulatory abnormalities, and a bone marrow examination revealed an increased number of megakaryocytes without any abnormal cells or blasts. No lymphadenopathy or hepatosplenomegaly was observed on computed tomography. She was initially diagnosed with immune thrombocytopenic purpura (ITP). None of the treatments administered for ITP produced a response. However, abnormal cells were eventually found during the third bone marrow examination. The pathological diagnosis was mature B-cell lymphoma. Rituximab-containing chemotherapy produced a marked increase in the patient's platelet count, and her lymphoma went into complete remission.

Pathology and classification of aggressive mature B-cell lymphomas.

Pathology and classification of aggressive mature B-cell lymphomas.

Development of in Vivo Models of Paediatric Burkitt Lymphoma Allowing Therapeutic Target Analysis and Drug Testing

Childhood sporadic Burkitt lymphoma (BL) is a highly aggressive mature B-cell lymphoma. Patients require intensive chemotherapy which results in prolonged periods of hospitalisation for distressing and dangerous side effects. Additionally those with refractory disease or those that relapse have an extremely poor prognosis. As a result, there is an urgent need to develop new targeted treatments that have undergone rigorous pre-clinical evaluation. The aim of this project is to develop improved models for target selection and pre-clinical validation to reduce the failure of translation of novel agents.Two models are being developed. Firstly, xenotransplantation of BL cell lines is being used to optimise transplantation protocols and to provide an orthotopic assay for in vivo functional genomic (RNAi) screening. This is currently being used in genome-wide target identification screens. Secondly, cryopreservation of viable BL blasts is allowing development of a patient-derived xenograft model, suitable for validation of candidate targets by both RNAi and pharmacological inhibition and for testing novel therapeutic agents.The sporadic BL cell lines CA46 and RAMOS have been transplanted into NOD/LtSz-scid IL-2Rg-/- (NSG) and RAG2-/-gc-/- (RAG2) mice at reducing cell doses (105, 104 and 103 cells/mouse). This approach will identify the optimal conditions for orthotopic engraftment. Prior to transplantation, cells were transduced with the lentiviral vector pSLIEW expressing green fluorescent protein (analysis and cell sorting) and firefly luciferase (in vivo bioluminescent imaging). Engraftment was then monitored in real-time using the Caliper in vivo imaging system (IVIS).CA46 and RAMOS cell lines have been transduced with SLIEW, sorted to high purity (>90%) and engrafted in both NGS and RAG2 mice. IVIS imaging of mice transplanted with CA46 cells showed that rate of engraftment was relative to cell dose. All six mice showed a bioluminescent signal over the femurs by 3 weeks post transplantation, indicative of bone marrow (BM) engraftment. Analysis of BM by flow cytometry confirmed engraftment in the two mice analysed, as determined by GFP positivity and presence of the human B-cell markers CD10, CD19 and CD20. Renal enlargement was observed in all mice analysed, with dense infiltration by mature lymphoid blasts evident microscopically. Immunohistochemistry confirmed infiltration with human CD20 positive cells. Splenic enlargement was observed in five out of six mice and engraftment was again confirmed histologically. Onset of disease was rapid. Mice were killed when they showed signs of ill health (see table).A similar pattern of engraftment was observed in NSG and RAG2 mice transplanted with RAMOS cells, although signal intensity was not relative to transplanted cell dose. Bioluminescent signal over the femur was detected in four out of six mice by 3 weeks post transplantation. NSG and RAG2 mice receiving 103 cells, with no IVIS signal, were negative for BM engraftment by flow cytometry. Renal enlargement was not observed, however focal renal lesions were evident macroscopically in three out of six mice. These lesions were composed of human CD20 positive cells. Splenic enlargement was not observed, although a degree of splenic engraftment was identified histologically. Onset of disease was also rapid.Following the initial cell line model development, we are now able to transplant the first patient-derived BL sample. If successful, primograft material will be labelled with luciferase (pSLIEW) and re-transplanted, allowing in vivo imaging. When combined with in vivo RNAi screening, this advanced pre-clinical model for target selection and validation may help reduce target drop-out during early phase clinical trials. This is a critical step, not only to avoid exposing children to ineffectual and potentially toxic drugs, but also to avoid delay in the development of new effective therapies. Abstract 5501. TableCA46DoseSpleenKidneyBMSurvival (days)RAMOSDoseSpleenKidneyBMSurvival (days)RAG2105+++++na29RAG2105+++++31104+++++++38104-/+-/++29103+++na38103--/+-39NSG105++na23NSG105-+++37104++++++31104-/+-/+na30103+++++na38103-++-39CD20 positivity for spleen and kidney; none (-), < 10% (-/+), 10 - 50% (+), > 50% (++), 100% (+++). For BM engraftment (CD10, CD19 and CD20 positive); no engraftment (-), engrafted (+), not assessed (na). DisclosuresNo relevant conflicts of interest to declare.

CD20‐positive plasmablastic lymphoma with excellent response to bortezomib combined with rituximab

As a distinct type of aggressive mature large B-cell lymphoma, plasmablastic lymphoma (PBL) poses diagnostic and treatment challenges. PBL is distinguished from other B-cell lymphomas by the presence of plasmacytic differentiation markers such as CD38, CD138, and MUM1. Clinically, PBLs from oral and extra-oral sites are rapidly progressive tumors with frequent relapse after treatment with standard diffuse large B-cell lymphoma regimens. Here, we report a near-complete response of one patient with relapsed PBL following treatment with a non-cytotoxic regimen containing bortezomib, rituximab, and dexamethasone.