BCL6 Rearrangements Research Articles

Outcome of high-grade B-cell lymphoma compared to other large B-cell lymphoma after CAR-T rescue. A DESCAR-T LYSA study.

High-grade-B-cell lymphoma (HGBL) with MYC and BCL2 and/or BCL6 rearrangements (double hit [HGBL-DH] or triple hit [HGBL-TH]), or not otherwise specified (HGBL-NOS), are considered to be more aggressive diseases among large B-cell lymphomas (LBCL). CD19-targeting Chimeric Antigen Receptor (CAR) T-cells have changed the prognosis of chemoresistant LBCL. Clinical and pathological data of patients treated for relapsed/refractory LBCL or HGBL in third line or more, all characterized by FISH, were collected from the French DESCAR-T registry. Between January 2018 and November 2022, 228 patients were included across 14 centers, 73 with HGBL (28 HGBL-DH MYC-BCL2, 14 HGBL-TH, 8 HGBL-DH MYC-BCL6, 23 HGBL-NOS) and 155 with non-HGBL. Median follow-up was 18.5 months [95% CI, 14.3-23.4] from the date of infusion. Progression-free survival (PFS) and overall survival (OS) were not significantly different between HGBL and non-HGBL, at respectively 3.2 months [95% CI, 2.8-6.0] vs 4.5 months [95% CI, 3.1-8.7] (p = 0.103) and 15.4 months [95% CI, 5.6-32.4] vs 18.3 months [95% CI, 8.5-NR]. From the date of eligibility, the median OS was inferior for patients with HGBL-TH/DH MYC-BCL2 at 6.6 months vs 18.5 months for HGBL-NOS vs 13.6 months for HGBL-DH MYC-BCL6 vs 11.8 months for LBCL (p = 0.037). However, infused patients presented the same outcome. CAR T-cell therapy used in third line or more seems to overcome the poor prognosis of HGBL subtypes, especially in HGBL-TH/DH MYC-BCL2. This observation supports considering the potential benefit of using CAR-T earlier in the course of the disease.

CD5-positive high-grade B-cell lymphoma with MYC, BCL2, and BCL6 rearrangements.

CD5-positive high-grade B-cell lymphoma with MYC, BCL2, and BCL6 rearrangements.

Diffuse Large B-Cell Lymphoma/High Grade B-Cell Lymphoma with MYC and BCL6 Rearrangements: a study of 60 Cases.

Classification of cases of diffuse large B-cell lymphoma (DLBCL)/high-grade B-cell lymphoma (HGBL) with MYC and BCL6 rearrangements, also known as BCL6 double hit lymphoma (DHL), is controversial. We assessed 60 cases of BCL6-DHL and compared this cohort to 224 cases of DHL with MYC and BCL2 rearrangements (BCL2-DHL) and 217 cases of DLBCL not otherwise specified. Compared with the DLBCL cohort, BCL6-DHL patients had more aggressive clinical features such as frequent extranodal involvement, high-stage disease, high IPI score and elevated serum lactate dehydrogenase level (p <0.01 for all). Compared with the BCL2-DHL cohort, BCL6-DHL patients had similarly aggressive clinical features but a lower frequency of germinal center B-cell (GCB) immunophenotype and MYC and BCL2 double expression. Patients with BCL6-DHL showed an overall survival (OS) intermediate between patients with DLBCL and BCL2-DHL. Following induction with R-CHOP chemotherapy, BCL6-DHL patients demonstrated a poor OS similar to BCL2-DHL patients and worse than that of DLBCL patients (p = 0.024). However, among patients who received R-EPOCH, there was no significant difference in OS among the three groups (p = 0.146). Gene expression profiling showed that 60% of BCL6-DHL cases had a double hit (DH)-like signature compared with 10% of DLBCL-GCB and 93% of BCL2-DHL. The DH-like signature in BCL6-DHL cases was associated with a GCB immunophenotype. Based on these data, we suggest that BCL6-DHL cases are clinically more aggressive than DLBCL and patients may benefit from a more aggressive therapy than R-CHOP. The data also suggest that BCL6-DHL as currently defined, is heterogeneous and that neoplasms with a GCB immunophenotype are more likely to have DH-like signature and behave more aggressively. Lastly, we suggest that BCL6-DHL cases deserve to be recognized separately in a lymphoma classification to facilitate further understanding of these neoplasms and for optimal patient management.

How I diagnose high-grade B-cell lymphoma.

High-grade B-cell lymphoma (HGBL), introduced in the 2016 World Health Organization (WHO) revised fourth edition classification, included cases defined by MYC and BCL2 and/or BCL6 rearrangements or by high-grade morphology. Diagnostic criteria and nomenclature for these lymphomas were refined in the 2022 WHO fifth edition (WHO-5) classification and International Consensus Classification (ICC). This review describes our approach to the diagnosis of HGBL. Two cases are presented illustrating how we diagnose HGBL, including 1 case harboring MYC and BCL6 rearrangements and a second showing TdT expression in an HGBL with MYC and BCL2 rearrangements. The ways in which these cases are distinguished from other lymphomas with high-grade features and the appropriate nomenclature using WHO-5 and ICC classifications are emphasized. An HGBL diagnosis requires integration of morphology, immunophenotype, and genetics and exclusion of other lymphomas with high-grade morphology, including Burkitt lymphoma, B-lymphoblastic leukemia/lymphoma (B-LBL/ALL), and blastoid mantle cell lymphoma. A diagnosis of HGBL/large B-cell lymphoma with 11q aberration should also be considered in certain patient populations. High-grade B-cell lymphomas are subclassified based on morphologic and genetic features. There are differences in the nomenclature and definition of these lymphomas in the WHO-5 and ICC classifications. Distinguishing HGBLs from other mature B-cell lymphomas and B-LBL/ALL is critical so that patients receive appropriate treatment.

Real-World Outcomes of Patients with High-Grade B-Cell Lymphoma with MYC and BCL2 rearrangements Treated in the Contemporary Era

Real-World Outcomes of Patients with High-Grade B-Cell Lymphoma with MYC and BCL2 rearrangements Treated in the Contemporary Era

MRI-based radiomics virtual biopsy for BCL6 in primary central nervous system lymphoma

To establish a machine learning model based on a radiomic signature for predicting B-cell lymphoma 6 (BCL-6) rearrangement in primary central nervous system lymphoma (PCNSL). Retrospective study on 102 PCNSL patients (31 with BCL-6 rearrangement positive, 71 with BCL-6 rearrangement negative) were randomly divided into the training and validation sets at a ratio of 7:3. Radiomics models based on contrast-enhanced T1-weighted imaging (CE-T1WI) and fluid-attenuated inversion recovery (FLAIR) in different regions, including VOItumour core and VOIperitumoural oedema. Radiomics features were extracted and selected using LASSO regression, and radiomics score (rad-score) were calculated using the weighted coefficients. Four machine learning models (logistic regression, random forest, support vector machine, K-nearest neighbours) were developed and evaluated based on rad-score. The optimal radiomics model was integrated into the clinical or radiological factors to construct a predictive model through logistic regression analysis. A nomogram was constructed based on independent significant features for individualised prediction. All rad-scores based on CE-T1WI and FLAIR sequences were significantly associated with BCL6 rearrangement (p < 0.05) in univariate regression analysis. The logistic regression machine learning model performed best with AUCs of 0.935 (training) and 0.923 (validation). Rad-scores from CE-T1WI tumour core and peritumoural oedema were independent significant predictors. Radiomics signatures based on CE-T1WI and FLAIR sequences have significant value in distinguishing BCL6 rearrangement. The CE-T1WI radiomics model based on VOItumour core and VOIperitumoural oedema are robust markers for identifying BCL6 rearrangement.

CNS relapse in high-grade B-cell lymphoma with MYC and BCL2 rearrangements and dark-zone signature–expressing DLBCL

AbstractHigh-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL-DH-BCL2), or “double-hit lymphoma,” has been associated with a high risk of central nervous system (CNS) relapse. However, historic estimates are impacted by selection bias. We report CNS relapse rates associated with HGBCL-DH-BCL2 from a population-based cohort with complete fluorescence in situ hybridization testing, as well as diffuse large B-cell lymphoma morphology (DLBCL) tumors expressing the dark-zone gene expression signature (DZsig), which was originally derived from HGBCL-DH-BCL2. The 2-year CNS relapse risk in HGBCL-DH-BCL2 was 6.8%. CNS relapses were early, predominantly leptomeningeal (73%), and co-occurred with systemic relapse (64%). High-risk CNS International Prognostic Index (CNS-IPI) and concordant bone marrow involvement were associated with an elevated CNS relapse risk in HGBCL-DH-BCL2. The “refined cell-of-origin” classification assigned 20% of DLBCL morphology tumors with germinal center B-cell–like phenotype (GCB-DLBCL) into a distinct subgroup based on DZsig expression (DZsig+). CNS relapse risk in DZsig+ (2 year: 6.4%) was independent of HGBCL-DH-BCL2 status and was further stratified by the CNS-IPI. CNS relapse in DZsig-negative GCB-DLBCL was rare (2-year risk, 1.4%; P = .04 vs DZsig+) and exclusively parenchymal. Altogether, the CNS relapse risk in HGBCL-DH-BCL2 is lower than previously reported, and DZsig refines risk stratification in GCB-DLBCL.

Primary central nervous system diffuse large B-cell lymphoma with MYC and BCL2 rearrangements associated with deep brain stimulation device.

Primary central nervous system (CNS) diffuse large B-cell lymphoma with MYC and BCL2 rearrangements is a very rare lymphoma subtype. Deep brain stimulation is an effective minimally invasive therapeutic option for the treatment of refractory movement disorders, as well as some psychiatric disorders and chronic pain syndromes. Herein, we report a case of CNS lymphoma, which developed around an electrode of a deep brain stimulation (DBS) device. A 70-year-old woman with drug-resistant essential tremor was treated with bilateral thalamic DBS with significant symptomatic improvement over the following year. She presented to the emergency department with recurrent tremor, blurred vision, and confusion. Imaging showed a 4 cm heterogeneously enhancing centered around the DBS electrode. Pathologic evaluation and systemic workup confirmed a diagnosis of primary CNS diffuse large B-cell lymphoma. MYC and BCL2 rearrangements were identified. To our knowledge, this is the first reported case of a CNS lymphoma associated with a DBS electrode.

An unusual case of a de novo high-grade B cell neoplasm with MYC and BCL2 rearrangements, strong TdT expression, and BRAF V600E mutation

Abstract Introduction/Objective Aggressive de novo B cell neoplasms can rarely exhibit overlapping features of B- lymphoblastic leukemia/lymphoma (B-ALL) and high-grade B cell lymphoma (HGBL) making their definitive classification challenging. The distinction between mature and immature B cell neoplasms is critical as treatment approaches differ. We report a unique case of an aggressive B cell neoplasm that not only posed diagnostic difficulties but was also found to harbor a BRAF V600E mutation, an unusual finding in such cases. Methods/Case Report A 33-year-old man without any significant past medical history presented for evaluation of a large tonsil mass and diffuse lymphadenopathy. The tonsil was excised, and histologic examination showed a diffuse atypical infiltrate composed of medium to large monomorphic lymphoid cells with high-grade cytology. By immunohistochemistry, the atypical cells were positive for CD19, CD79a, CD22, PAX5, CD10 (strong), CD45 (strong), BCL2, MYC, and TdT (strong). Ki67 showed a high proliferation index (80%). The atypical cells were negative for CD20, CD34, CD1a, CD30, Cyclin D1, T cell markers, myeloid markers, HHV8, and EBER. Flow cytometry detected a CD10 positive B cell population that was negative for CD20, CD34, and surface light chain expression. Fluorescence in-situ hybridization (FISH) detected BCL2 and MYC rearrangements. Staging marrow showed diffuse involvement by a neoplastic infiltrate with similar features to those observed in the tonsil. Chromosome analysis showed a complex karyotype. The patient was treated with two cycles of da-EPOCH-R. A neck lymph node biopsy two months later showed persistent disease. Next-generation sequencing (NGS) on this sample demonstrated a BRAF V600E mutation at 31% allele frequency. A mutation-specific BRAF-VE1 immunostain was diffusely positive. Results (if a Case Study enter NA) NA Conclusion This was a diagnostically challenging case of a de novo B-cell lineage neoplasm with high-grade features, MYC and BCL2 rearrangements, and strong diffuse TdT expression. There is limited literature on mutational profiles and prognostic data for such cases, and whether they are best classified (and treated) as HGBL or B-ALL remains challenging and controversial. In our case, we also discovered an unexpected finding of a BRAF V600E mutation, which has not been reported in similar cases in the existing literature and could serve as a potential therapeutic target. Additional reporting and genetic profiling of such cases may help further elucidate their biology and guide treatment protocols.

Composite Lymphoma Comprising of BCL2 Rearrangement Negative, CD23 Positive Follicle Center Cell Lymphoma and Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Case Report

Abstract Introduction/Objective BCL2 rearrangement negative, CD23-positive follicle center cell lymphoma (BCL2 neg CD23 pos FCL) is a rare, recently described provisional entity in International Consensus Classification (2022). It has a predominantly diffuse growth pattern and often involves inguinal region. The molecular profile includes a high frequency of STAT6 and CREBBP co-mutation as well as 1q gain and a recurrent 1p36 loss/TNFRS14 abnormalities. We describe a composite tumor comprising of a rare entity BCL2 neg CD23 pos FCL and Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL). To the best of our knowledge this is the first reported case description of this co-occurrence. Methods/Case Report A 59 y/o woman presented with right cervical and axillary lymphadenopathy (upto 1.6 cm). Sections showed partial effacement of nodal architecture by interfollicular and diffuse proliferation of atypical lymphoid cells. The interfollicular areas were comprised of a monotonous population of small lymphocytes. Immunohistochemical stains performed showed that the interfollicular CD20+ PAX5+ atypical lymphoid cells coexpressed CD5, CD23, BCL2 and LEF1 and were negative for CD10, BCL6, CD3, and SOX11, with MIB1 of 5-10%. Based on these, a diagnosis of CLL/SLL was made. Admixed with the CLL/SLL, a second neoplastic B-cell component that distorted nodal architecture was also identified. It composed of a diffuse proliferation of intermediate sized lymphoid cells with a centrocytic/centroblastic morphology. This smaller population of small to intermediate sized B cells expressed CD10, BCL6, and CD23 with a MIB1 proliferation index of ~30%. This population was CD5 and BCL2 negative. CD21 showed residual follicular dendritic cell meshworks. SOX11 and BCL1 were negative. Therefore, a diagnosis of BCL2 neg CD23 pos FCL was made. Flow cytometry showed two distinct populations of monotypic B-cells, one CD5-positive and the other CD10-positive. FISH studies were negative for BCL2 and BCL6 rearrangements as well as del1p36. Cytogenetics was positive for trisomy 12, supporting CLL/SLL. Next Generation Sequencing showed Tier 1 / 2 mutations in STAT6, TNFRSF14, CREBBP, and FOXO1, supporting BCL2 neg CD23 pos FCL. Hence, this represents a unique case of composite CLL/SLL and BCL2 neg CD23 pos FCL. B cell gene rearrangement showed 2 distinct clones confirming 2 separate B cell lymphomas. Results (if a Case Study enter NA) NA Conclusion Here, we describe a composite CLL/SLL and BCL2 rearrangement negative, CD23 positive, FCL never previously described in literature.

Molecular Classification of Large B-Cell Lymphoma and High-Grade B-Cell Lymphoma Cases and Association with Outcomes in Morocco

Background: High-grade B-cell lymphoma with c-MYC and BCL2 and/or BCL6 rearrangements (HGBL-DHL/THL) is a recently identified category in the most recent World Health Organization (WHO) classification. For all tumors displaying the appearance of diffuse large B-cell lymphoma (DLBCL) or high-grade B-cell lymphoma (HGBL), it is necessary to perform fluorescence in situ hybridization (FISH) in order to achieve an accurate diagnosis. The findings of FISH and immunohistochemistry (IHC) examinations from 50 DLBCL/HGBL samples obtained from Hassan II University Hospital in Fez/Morocco are reported. Methods: This retrospective study included 50 patients diagnosed with DLBCL/HGBL over a period of nine years (2013–2022) and treated with RCHOP chemotherapy protocol. All patients underwent a histological study followed by an immunohistochemical study to confirm the diagnosis and to classify patients according to cell of origin into non-GCB and GCB subtypes; then, a cytogenetic study using FISH was performed to classify patients according to the presence or absence of rearrangements in the c-MYC, BCL2 and BCL6 genes. A comparison was made between the molecular subtypes of DLBCL/HGBL in relation to clinicopathological features and outcomes. Results: Among the 50 cases studied in our population, we found 5 cases of HGBL with DLBCL morphology and 45 cases of DLBCL, which consisted of 13 cases (28.89%) of GCB subtype and 32 cases (71.11%) of non-GCB subtype based on the immunohistochemistry Hans algorithm. After FISH testing of all cases, we found three cases of double-hit lymphoma (DHL) and one case of triple-hit lymphoma (THL). Thus, HGBL-DHL/THL accounted for 8% of the cases. Furthermore, two cases were detected with only one rearrangement in the BCL2 gene and one case harboring a rearrangement in the BCL6 gene. DHL and THL patients and patients with a single rearrangement (BCL2 or BCL6) have a worse prognosis than patients with no rearrangement. Conclusions: DHL and THL are an aggressive entity of HGBL with poorer outcomes in comparison to DLBCL/HGBL NOS. First-line treatment with the RCHOP chemotherapy protocol may not be effective for all aggressive DLBCL cases. More targeted treatment is crucial for better patient outcomes.

Testicular large B-cell lymphoma is genetically similar to PCNSL and distinct from nodal DLBCL.

Testicular large B-cell lymphoma (TLBCL) is an infrequent and aggressive lymphoma arising in an immune-privileged site and has recently been recognized as a distinct entity from diffuse large B-cell lymphoma (DLBCL). We describe the genetic features of TLBCL and compare them with published series of nodal DLBCL and primary large B-cell lymphomas of the CNS (PCNSL). We collected 61 patients with TLBCL. We performed targeted next-generation sequencing, copy number arrays, and fluorescent in situ hybridization to assess chromosomal rearrangements in 40 cases with available material. Seventy percent of the cases showed localized stages. BCL6 rearrangements were detected in 36% of cases, and no concomitant BCL2 and MYC rearrangements were found. TLBCL had fewer copy number alterations (p < 0.04) but more somatic variants (p < 0.02) than nodal DLBCL and had more frequent 18q21.32-q23 (BCL2) gains and 6q and 9p21.3 (CDKN2A/B) deletions. PIM1, MYD88 L265P , CD79B, TBL1XR1, MEF2B, CIITA, EP300, and ETV6 mutations were more frequent in TLBCL, and BCL10 mutations in nodal DLBCL. There were no major genetic differences between TLBCL and PCNSL. Localized or disseminated TLBCL displayed similar genomic profiles. Using LymphGen, the majority of cases were classified as MCD. However, we observed a subgroup of patients classified as BN2, both in localized and disseminated TLBCL, suggesting a degree of genetic heterogeneity in the TLBCL genetic profile. TLBCL has a distinctive genetic profile similar to PCNSL, supporting its recognition as a separate entity from DLBCL and might provide information to devise targeted therapeutic approaches.

Large B-cell lymphomas with CCND1 rearrangement have different immunoglobulin gene breakpoints and genomic profile than mantle cell lymphoma

Mantle cell lymphoma (MCL) is genetically characterized by the IG::CCND1 translocation mediated by an aberrant V(D)J rearrangement. CCND1 translocations and overexpression have been identified in occasional aggressive B-cell lymphomas with unusual features for MCL. The mechanism generating CCND1 rearrangements in these tumors and their genomic profile are not known. We have reconstructed the IG::CCND1 translocations and the genomic profile of 13 SOX11-negative aggressive B-cell lymphomas using whole genome/exome and target sequencing. The mechanism behind the translocation was an aberrant V(D)J rearrangement in three tumors and by an anomalous IGH class-switch recombination (CSR) or somatic hypermutation (SHM) mechanism in ten. The tumors with a V(D)J-mediated translocation were two blastoid MCL and one high-grade B-cell lymphoma. None of them had a mutational profile suggestive of DLBCL. The ten tumors with CSR/SHM-mediated IGH::CCND1 were mainly large B-cell lymphomas, with mutated genes commonly seen in DLBCL and BCL6 rearrangements in 6. Two cases, which transformed from marginal zone lymphomas, carried mutations in KLF2, TNFAIP3 and KMT2D. These findings expand the spectrum of tumors carrying CCND1 rearrangement that may occur as a secondary event in DLBCL mediated by aberrant CSR/SHM and associated with a mutational profile different from that of MCL.

Double-hit primary central nervous system lymphoma with histogenetically proven bone marrow infiltration: a case report and a review of the literature.

Double-hit lymphoma (DHL) formerly referred to high-grade B-cell lymphoma with concurrent MYC and BCL2 or BCL6 rearrangements, however, the updated 2022 World Health Organization Classification (5th edition online) excludes those with MYC and BCL 6 rearrangements from the high-grade category. DHL confined to the central nervous system (CNS), known as double-hit primary CNS lymphoma (DH-PCNSL), is rare with poorly understood clinical features. Here, we report a case of a 64-year-old man with multiple brain tumors diagnosed with DH-PCNSL who showed bone marrow (BM) infiltration early in the clinical course. The histological diagnosis was high-grade B-cell lymphoma with MYC and BCL6 rearrangements. Fluorodeoxyglucose positron emission tomography (FDG-PET) revealed no abnormal accumulation except in the CNS. The patient received whole-brain radiotherapy following the failure of high-dose methotrexate. After completion of radiotherapy, the patient developed thrombocytopenia, and BM biopsy showed infiltration of DHL cells, which were not detected by repeated FDG-PET. This is the first report of DH-PCNSL where identical gene rearrangements were confirmed in both the resected CNS tumor and BM tissue. Patients with DH-PCNSL require careful follow-up because they may be at a potential risk of BM infiltration, which may be undetectable by FDG-PET, particularly early in the disease course.

Clinicopathological and Molecular Characteristics of Rare EBV-associated Diffuse Large B-cell Lymphoma With IRF4 Rearrangement.

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (DLBCL) is a rare form of aggressive B-cell lymphoma with limited molecular information reported regarding interferon regulatory factor 4 ( IRF4 ) status. Here, we presented 3 EBV-positive DLBCL cases with IRF4 rearrangement (EBV+DLBCL- IRF4 -R) verified by fluorescence in situ hybridization (FISH). Three patients, including 1 male and 2 females (median age: 64y; range: 45 to 68y), had normal immune function. During a median follow-up of 12 months (range: 0 to 24 mo), 2 patients succumbed to the disease, and 1 patient achieved complete response. Three tumors were present in the mediastinum, stomach, and thalamus, respectively. All three tumors exhibited DLBCL morphology and were identified as the non-germinal center B-cell subtype, with EBV-encoded small RNA positivity ranging from 70% to 80%. RNA sequencing was able to identify RHOH and IGH as fusion partners of IRF4 in two cases. No MYC and BCL2 rearrangements were detected in 3 cases by FISH and RNA sequencing. Next-generation sequencing revealed a low mutation burden, and only IRF4 was recurrently mutated in two EBV+DLBCL- IRF4 -R cases. Using the LymphGen 2.0 classifier, 1 case was classified as the MCD (including MYD88L265P and CD79B mutations) subtype. We report rare EBV+DLBCL- IRF4 -R that may enhance our understanding of the diverse spectrum of large B-cell lymphoma.

Unbalanced MYC break-apart FISH patterns indicate the presence of a MYC rearrangement in HGBCL-DH-BCL2

AbstractFluorescence in situ hybridization (FISH) using break-apart probes is recommended for identifying high-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL-DH-BCL2). Unbalanced MYC break-apart patterns, in which the red or green signal is lost, are commonly reported as an equivocal result by clinical laboratories. In a cohort of 297 HGBCL-DH-BCL2, 13% of tumors had unbalanced MYC break-apart patterns with loss of red (LR; 2%) or loss of green (LG; 11%) signal. To determine the significance of these patterns, MYC rearrangements were characterized by sequencing in 130 HGBCL-DH-BCL2, including 3 LR and 14 LG tumors. A MYC rearrangement was identified for 71% of tumors with LR or LG patterns, with the majority involving immunoglobulin loci or other recurrent MYC rearrangement partners. The architecture of these rearrangements consistently preserved the rearranged MYC allele, with the MYC gene predicted to be on the derivative chromosome containing the signal that is still present in nearly all cases. MYC protein expression, MYC messenger RNA expression, and the proportion of tumors expressing the dark-zone signature was not significantly different between balanced and unbalanced groups. These results support a recommendation that unbalanced MYC break-apart FISH patterns be reported as positive for MYC rearrangement in the context of diagnosing HGBCL-DH-BCL2.

Interim efficacy of a multicenter cohort study for China Net Childhood Lymphoma mature B-cell lymphoma 2017 regimen in the treatment of pediatric High-grade-B cell lymphoma

Objective: To analyze the mid-term efficacy of the China Net Childhood Lymphoma mature B-cell lymphoma 2017 (CNCL-B-NHL-2017) regimen in treating children with high-grade B-cell lymphoma (HGBL). Methods: Clinical and pathological data of HGBL children aged≤18 years admitted to 16 hospitals of the Chinese Children's Lymphoma Collaborative Group (CNCL) from May 2017 to April 2021 were collected retrospectively. They were divided in to high-grade B-cell lymphoma with double hit/triple hit (HGBL-DH/TH) group and high-grade B-cell lymphoma non-specified (HGBL-NOS) group, according to the 2016 version of the World Health Organization (WHO) Hematopoietic and Lymphoid Tissues Cancer Classification. Both groups of patients were treated with stratified chemotherapy by risk according to the CNCL-B-NHL-2017 scheme. The deadline for follow-up was December 31, 2023. All the patients were examined by chromosome fluorescence in situ hybridization (FISH), and the rearrangement of genes MYC, BCL-2 and BCL-6 was confirmed. The clinical and pathological characteristics of patients at disease onset were analyzed, and the therapeutic effects of patients in different clinical stages and risk groups were compared. Survival analysis was drawn by Kaplan Meier method, the log-rank test was used to compare the differences in the cumulative survival rate between different groups, and multivariate Cox regression model was used to identify the prognostic factors. Results: A total of 62 patients were included, with an onset age [M(Q1, Q3)] of 7 (4, 11) years, including 48 males and 14 females. There were 11 (17.7%) patients in stageⅡ, 33(53.2%)patients in stage Ⅲ and 18(29.1%)patients in stage Ⅳ. FISH testing showed that 4 cases (6.5%) were HGBL-DH and 3 (4.8%) were HGBL-TH. The remaining 55 cases (88.7%) were HGBL-NOS, with 18 cases accompanied by MYC rearrangement. There were 7 cases in the HGBL-DH/TH group and 55 cases in the HGBL-NOS group. Thirteen cases (20.9%) were treated with the B1 regimen, 3 cases (4.8%) with B2 regimen, 37 cases (59.6%) with C1 regimen, and 9 cases (14.7%) with the C2 regimen. Forty-eight cases (77.4%) received rituximab therapy at the same time. Five cases (8.0%) progressed during treatment. The follow-up time [M(Q1, Q3)] was 43.5 (36.1, 53.7) months. The complete remission rate was 91.9% (57/62). The 3 year overall survival rate was 93.5% and event-free survival (EFS) rate was 91.9%. The 3-year overall survival rate in the HGBL-NOS group was higher than that in the HGBL-DH/TH group (96.3% vs 71.4%, P=0.011). The 3-year EFS rate of the HGBL-NOS group was higher than that of the HGBL-DH/TH group (94.5% vs 71.4%, P=0.037). In the HGBL-NOS subgroup, the overall survival rate of children with MYC rearrangement was lower (100% vs 88.9%,P=0.039). Multivariate Cox regression analysis showed that central invasion (HR=6.05, 95%CI: 1.96-38.13, P=0.046) was a risk factor for overall survival. Conclusion: CNCL-B-NHL-2017 regimen shows significant effects in the treatment of pediatric HGBL, with a good prognosis.

Characteristics and Clinical Value of MYC , BCL2, and BCL6 Rearrangement Detected by Next-generation Sequencing in DLBCL.

MYC , BCL2, and BCL6 rearrangements are clinically important events of diffuse large B-cell lymphoma (DLBCL). The ability and clinical value of targeted next-generation sequencing (NGS) in the detection of these rearrangements in DLBCL have not been fully determined. We performed targeted NGS (481-gene-panel) and break-apart FISH of MYC , BCL2, and BCL6 gene regions in 233 DLBCL cases. We identified 88 rearrangements (16 MYC ; 20 BCL2 ; 52 BCL6 ) using NGS and 96 rearrangements (28 MYC ; 20 BCL2 ; 65 BCL6 ) using FISH. The consistency rates between FISH and targeted NGS for the detection of MYC , BCL2, and BCL6 rearrangements were 93%, 97%, and 89%, respectively. FISH-cryptic rearrangements (NGS+/FISH-) were detected in 7 cases (1 MYC ; 3 BCL2 ; 2 BCL6 ; 1 MYC::BCL6 ), mainly caused by small chromosomal insertions and inversions. NGS-/FISH+ were detected in 38 cases (14 MYC ; 4 BCL2 ; 20 BCL6 ).To clarify the cause of the inconsistencies, we selected 17 from the NGS-/FISH+ rearrangements for further whole genome sequencing (WGS), and all 17 rearrangements were detected with break points by WGS. These break points were all located outside the region covered by the probe of targeted NGS, and most (16/17) were located in the intergenic region. These results indicated that targeted NGS is a powerful clinical diagnostics tool for comprehensive MYC , BCL2, and BCL6 rearrangement detection. Compared to FISH, it has advantages in describing the break point distribution, identifying uncharacterized partners, and detecting FISH-cryptic rearrangements. However, the lack of high-sensitivity caused by insufficient probe coverage is the main limitation of the current technology.

Targeted inhibition of DHODH is synergistic with BCL2 blockade in HGBCL with concurrent MYC and BCL2 rearrangement

High-grade B-cell lymphoma (HGBCL), the subtype of non-Hodgkin lymphoma, to be relapsed or refractory in patients after initial therapy or salvage chemotherapy. Dual dysregulation of MYC and BCL2 is one of the important pathogenic mechanisms. Thus, combined targeting of MYC and BCL2 appears to be a promising strategy. Dihydroorotate dehydrogenase (DHODH) is the fourth rate-limiting enzyme for the de novo biosynthesis of pyrimidine. It has been shown to be a potential therapeutic target for multiple diseases. In this study, the DHODH inhibitor brequinar exhibited growth inhibition, cell cycle blockade, and apoptosis promotion in HGBCL cell lines with MYC and BCL2 rearrangements. The combination of brequinar and BCL2 inhibitors venetoclax had a synergistic inhibitory effect on the survival of DHL cells through different pathways. Venetoclax could upregulate MCL-1 and MYC expression, which has been reported as a resistance mechanism of BCL2 inhibitors. Brequinar downregulated MCL-1 and MYC, which could potentially overcome drug resistance to venetoclax in HGBCL cells. Furthermore, brequinar could downregulate a broad range of genes, including ribosome biosynthesis genes, which might contribute to its anti-tumor effects. In vivo studies demonstrated synergetic tumor growth inhibition in xenograft models with brequinar and venetoclax combination treatment. These results provide preliminary evidence for the rational combination of DHODH and BCL2 blockade in HGBCL with abnormal MYC and BCL2.

Molecular characterization of a rare case of high-grade B-cell lymphoma with MYC, BCL2, BCL6, and CCND1 rearrangements

Quadruple-hit lymphomas are extremely rare non-Hodgkin lymphomas with a reported dismal prognosis in the few reported cases. A “quadruple hit” has been defined by the presence of concurrent MYC, BCL2, BCL6, and CCND1 chromosomal rearrangements. We report a new case of a quadruple hit lymphoma in a 73-year-old Hispanic man who presented with an enlarging left-sided neck mass. Computed tomography showed a 1.9-cm mass in left the tonsil with bulky cervical lymphadenopathy. The presence of all four chromosomal rearrangements can reportedly occur with disease progression in both diffuse large B-cell lymphomas and mantle cell lymphomas. Further characterization of the tumor by next-generation sequencing may be of benefit to delineate between these two possibilities. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and next-generation sequencing were used to confirm and classify the diagnosis. Histologic sections of the cervical lymph node demonstrated an atypical lymphoid infiltrate with large and pleomorphic cells, which were positive for CD20, CD10, BCL1 (Cyclin D1), BCL2, BCL6, and cMYC and negative for CD5 and SOX11 on immunohistochemistry with a Ki-67 proliferative index of 70%. FISH demonstrated MYC, BCL2, BCL6, and CCND1 rearrangements and the diagnosis of high-grade B-cell lymphoma with MYC, BCL2, BCL6, and CCND1 was rendered. Our patient was treated with dose adjusted etoposide, doxorubicin, cyclophosphamide, prednisone, and rituximab chemotherapy and has been in remission for 20 months.