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Pediatric non-Hodgkin lymphoma includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the US, compared to >60,000 cases of adult NHL annually. Improvements in survival in pediatric and adolescent mature B cell NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes through dose escalation of chemotherapy and, more recently, targeted therapy with rituximab. Pediatric dose-intense strategies carry risks of long-term consequences, but treatment failure is nearly universally fatal. By comparison, adult mature B cell lymphoma is typically less aggressive and treated with less intense chemotherapy. Optimizing therapy for adolescents and young adults remains a major challenge that requires creative solutions, including engineering study groups to combine biologically comparable adult and pediatric populations and developing effective salvage strategies that will ultimately be required for investigations of front-line dose reduction. In this review, we discuss challenges and opportunities for improving outcomes for adolescents and young adults with high-grade mature B cell lymphomas, diffuse large B cell lymphoma, and primary mediastinal B cell lymphoma.

Abstract Pediatric non‐Hodgkin lymphoma includes over 30 histologies (many with subtypes), with approximately 800 cases per year in the US, compared to >60,000 cases of adult NHL annually. Improvements in survival in pediatric and adolescent mature B cell NHL over the past 5 decades align with the overall success of the cooperative trial model with dramatic improvements in outcomes through dose escalation of chemotherapy and, more recently, targeted therapy with rituximab. Pediatric dose‐intense strategies carry risks of long‐term consequences, but treatment failure is nearly universally fatal. By comparison, adult mature B cell lymphoma is typically less aggressive and treated with less intense chemotherapy. Optimizing therapy for adolescents and young adults remains a major challenge that requires creative solutions, including engineering study groups to combine biologically comparable adult and pediatric populations and developing effective salvage strategies that will ultimately be required for investigations of front‐line dose reduction. In this review, we discuss challenges and opportunities for improving outcomes for adolescents and young adults with high‐grade mature B cell lymphomas, diffuse large B cell lymphoma, and primary mediastinal B cell lymphoma.

Introduction: Diffuse large B-cell lymphoma (DLBCL) and primary mediastinal Bcell lymphoma (PMBCL) are aggressive histological subtypes of non-Hodgkin’s lymphoma. Improved understanding of the underlying molecular pathogenesis has led to new classification and risk stratification tools, including the development of cell-free biomarkers through liquid biopsies. The goal of this study was to investigate cell-free RNA (cfRNA) biomarkers in DLBCL and PMBCL patients. Materials and methods: Blood plasma samples (n=168) and matched diagnostic formalin-fixed paraffin-embedded (FFPE) tissue samples (n=69) of DLBCL patients, PMBCL patients and healthy controls were collected between 2016- 2021. Plasma samples were collected at diagnosis, at interim evaluation, after treatment, and in case of refractory or relapsed disease. RNA was extracted from 200 µl plasma using the miRNeasy serum/plasma kit and from FFPE tissue using the miRNeasy FFPE kit. RNA was subsequently sequenced on a NovaSeq 6000 instrument using the SMARTer Stranded Total RNA-seq pico v3 library preparation kit. Results: Higher cfRNA concentrations were demonstrated in lymphoma patients compared to healthy controls. A large number of differentially abundant genes were identified between the cell-free transcriptomes of DLBCL patients, PMBCL patients, and healthy controls. Overlap analyses with matched FFPE samples showed that blood plasma has a unique transcriptomic profile that significantly differs from that of the tumor tissue. As a good concordance between tissue derived gene expression and the immunohistochemistry Hans algorithm for cellof-origin (COO) classification was demonstrated in the FFPE samples, but not in the plasma samples, a 64-gene cfRNA classifier was developed that can accurately determine COO in plasma. High plasma levels of a 9-gene signature (BECN1, PRKCB, COPA, TSC22D3, MAP2K3, UQCRHL, PTMAP4, EHD1, NAP1L1 pseudogene) and a 5-gene signature (FTH1P7, PTMAP4, ATF4, FTH1P8, ARMC7) were significantly associated with inferior progression-free and overall survival in DLBCL patients, respectively, independent of the NCCN-IPI score. Conclusion: Total RNA sequencing of blood plasma samples allows the analysis of the cell-free transcriptome in DLBCL and PMBCL patients and demonstrates its unexplored potential in identifying diagnostic, cell-of-origin, and prognostic cfRNA biomarkers. [ABSTRACT FROM AUTHOR]

Primary mediastinal large B-cell lymphoma is a rare subtype of lymphoma. The contemporary incidence of primary mediastinal large B-cell lymphoma remains unknown, and a large population-based study has not been reported. It is essential to provide guidance for further strategies in reducing the disease burden via population-based preventive initiatives. This study aims to explore the epidemiology and effect of therapeutic advances on the survival of patients with primary mediastinal large B-cell lymphoma. This population-based study was conducted using the Surveillance, Epidemiology, and End Results Program (SEER), covering the period from 1975 to 2018. A total of 774 patients in the SEER 9 and 1654 patients in the SEER 18 were analyzed. The age-adjusted incidence rate of primary mediastinal large B-cell lymphoma increased from 0.05/1,000,000 in 1975 to 2.38/1,000,000 in 2018. A significant positive linear increase in the incidence trend was found in primary mediastinal large B-cell lymphoma, with an annual percent change of 8.47% (95% confidence interval 7.7-9.2%, P < 0.001, z test). The survival in primary mediastinal large B-cell lymphoma was significantly superior to nodal diffuse large B-cell lymphoma. The incidence of PMBCL increases over the year. The survival of patients with primary mediastinal large B-cell lymphoma has improved over time. [ABSTRACT FROM AUTHOR]

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy actually represents the standard of care for multiple relapsed or refractory primary mediastinal B-cell lymphoma (r/r PMBCL). Checkpoint inhibitors, such as pembrolizumab, appear to be a safe and effective treatment strategy for patients who are ineligible for or resistant to autologous stem cell transplantation. Although preclinical studies suggested that checkpoint inhibitors may enhance the vitality and anti-tumor activity of CAR T cells, there are no substantial/robust clinical data about the immune-mediated toxicity of their association. We describe a case of a severe cutaneous adverse event arising immediately after Cytokine Release Syndrome (CRS) on day +6 from CAR T cells infusion in a young r/r PMBCL patient who previously received pembrolizumab. These skin lesions were interpreted as an immune mediated adverse event, considering their prompt improvement and fully recovering achieved with the addition of immunoglobulin infusion to systemic steroid therapy. This case of life-threatening cutaneous adverse event calls for further investigations about off-target immune-related adverse events deriving from the combination of CAR T cell therapy and checkpoint inhibition, whose synergic therapeutic effect is promising. [ABSTRACT FROM AUTHOR]

Anti-CD19 chimeric antigen receptor (CAR) T cell therapy actually represents the standard of care for multiple relapsed or refractory primary mediastinal B-cell lymphoma (r/r PMBCL). Checkpoint inhibitors, such as pembrolizumab, appear to be a safe and effective treatment strategy for patients who are ineligible for or resistant to autologous stem cell transplantation. Although preclinical studies suggested that checkpoint inhibitors may enhance the vitality and anti-tumor activity of CAR T cells, there are no substantial/robust clinical data about the immune-mediated toxicity of their association. We describe a case of a severe cutaneous adverse event arising immediately after Cytokine Release Syndrome (CRS) on day +6 from CAR T cells infusion in a young r/r PMBCL patient who previously received pembrolizumab. These skin lesions were interpreted as an immune mediated adverse event, considering their prompt improvement and fully recovering achieved with the addition of immunoglobulin infusion to systemic steroid therapy. This case of life-threatening cutaneous adverse event calls for further investigations about off-target immune-related adverse events deriving from the combination of CAR T cell therapy and checkpoint inhibition, whose synergic therapeutic effect is promising.

Primary mediastinal B-cell lymphoma (PMBCL) is the only non-Hodgkin’s lymphoma variant responding to immune checkpoint inhibitor (ICI) therapy, approximately in half of the cases; however, no molecular markers predicting a response to ICI therapy in PMBCL have been described so far. In this study, we assessed the incidence of the loss of heterozygosity (LOH), elevated microsatellite alteration at selected tetranucleotides (EMAST), and microsatellite instability (MSI) in the tumor genomes of 72 patients with PMBCL undergoing high-dose chemotherapy treatment at the National Research Center for Hematology (Moscow, Russia). Tumor DNA was isolated from biopsy samples taken at diagnosis. Control DNA was isolated from the blood of patients in complete remission or from buccal epithelium. STR-profiles for LOH and EMAST were assessed by PCR with COrDIS Plus multiplex kit (Gordiz Ltd., Moscow, Russia). LOH was detected in 37 of 72 patients (51.4%). EMAST was found in 40 patients (55.5%); 24 had a combination of EMAST with LOH. MSI-high was not found, while MSI-low was detected only in one patient. The association of certain genetic lesions with the clinical outcome in patients receiving treatment according to the standard clinical protocol R-Da-EPOCH-21 has been estimated (58 patients out of 72) and no associations with the worst overall or event-free survival were found.

Abstract Patients with high‐risk aggressive B‐cell lymphoma exhibit poor survival after R‐CHOP. More intensive regimens yield higher rates of remission but also of complication. We investigated all 401 patients

Primary mediastinal B-cell lymphoma (PMBCL) is the only non-Hodgkin's lymphoma variant responding to immune checkpoint inhibitor (ICI) therapy, approximately in half of the cases; however, no molecular markers predicting a response to ICI therapy in PMBCL have been described so far. In this study, we assessed the incidence of the loss of heterozygosity (LOH), elevated microsatellite alteration at selected tetranucleotides (EMAST), and microsatellite instability (MSI) in the tumor genomes of 72 patients with PMBCL undergoing high-dose chemotherapy treatment at the National Research Center for Hematology (Moscow, Russia). Tumor DNA was isolated from biopsy samples taken at diagnosis. Control DNA was isolated from the blood of patients in complete remission or from buccal epithelium. STR-profiles for LOH and EMAST were assessed by PCR with COrDIS Plus multiplex kit (Gordiz Ltd., Moscow, Russia). LOH was detected in 37 of 72 patients (51.4%). EMAST was found in 40 patients (55.5%); 24 had a combination of EMAST with LOH. MSI-high was not found, while MSI-low was detected only in one patient. The association of certain genetic lesions with the clinical outcome in patients receiving treatment according to the standard clinical protocol R-Da-EPOCH-21 has been estimated (58 patients out of 72) and no associations with the worst overall or event-free survival were found. [ABSTRACT FROM AUTHOR]

Up to 60% of patients with aggressive B-cell lymphoma who receive chimeric antigen receptor (CAR) T-cell therapy experience treatment failure and subsequently have a poor prognosis. Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains a potentially curative approach for patients in this situation. Induction of a deep response prior to alloHSCT is crucial for long-term outcomes, but the optimal bridging strategy following relapse after CAR T-cell therapy has not yet been established. Polatuzumab vedotin, an antibody drug conjugate targeting CD79b, is a novel treatment option for use in combination with rituximab and bendamustine (Pola-BR) in relapsed or refractory disease. Patients: We report two heavily pretreated patients with primary refractory diffuse large B-cell lymphoma (DLBCL) and primary mediastinal B-cell lymphoma (PMBCL) respectively who relapsed after therapy with CAR T-cells with both nodal and extranodal manifestations of the disease. After application of three courses of Pola-BR both patients achieved a complete metabolic remission. Both patients underwent alloHSCT from a human leukocyte antigen (HLA)-mismatched donor following conditioning with busulfan and fludarabine and are disease free 362 days and 195 days after alloHSCT respectively. We conclude that Pola-BR can be an effective bridging therapy before alloHSCT of patients relapsing after CAR T-cell therapy. Further studies will be necessary to define the depth and durability of remission of this salvage regimen before alloHSCT. [ABSTRACT FROM AUTHOR]

Up to 60% of patients with aggressive B-cell lymphoma who receive chimeric antigen receptor (CAR) T-cell therapy experience treatment failure and subsequently have a poor prognosis. Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains a potentially curative approach for patients in this situation. Induction of a deep response prior to alloHSCT is crucial for long-term outcomes, but the optimal bridging strategy following relapse after CAR T-cell therapy has not yet been established. Polatuzumab vedotin, an antibody drug conjugate targeting CD79b, is a novel treatment option for use in combination with rituximab and bendamustine (Pola-BR) in relapsed or refractory disease. Patients: We report two heavily pretreated patients with primary refractory diffuse large B-cell lymphoma (DLBCL) and primary mediastinal B-cell lymphoma (PMBCL) respectively who relapsed after therapy with CAR T-cells with both nodal and extranodal manifestations of the disease. After application of three courses of Pola-BR both patients achieved a complete metabolic remission. Both patients underwent alloHSCT from a human leukocyte antigen (HLA)-mismatched donor following conditioning with busulfan and fludarabine and are disease free 362 days and 195 days after alloHSCT respectively. We conclude that Pola-BR can be an effective bridging therapy before alloHSCT of patients relapsing after CAR T-cell therapy. Further studies will be necessary to define the depth and durability of remission of this salvage regimen before alloHSCT.

Abstract The expression of programmed cell death ligand 1 (PD‐L1) is a biomarker for immunotherapy, but approved detection method is absent in diffuse large B‐cell lymphoma (DLBCL). Here, we performed three methods including immunohistochemistry (IHC) (clone SP263 and SP142), RNAscope, and fluorescence in situ hybridization (FISH) to evaluate PD‐L1 status on a cohort of DLBCL including 94 of DLBCL‐NOS, 25 of primary mediastinal large B‐cell lymphoma (PMBCL) and 7 of double‐hit lymphoma (DHL). SP263 with 25% for immune cell (IC) or combined cell and SP142 with 10% for tumor cell (TC), 20% for both of IC and combined cell were proved to have corresponding survival prognostic. Combined+ showed comparable prognostic value with TC+ and IC+. SP263 and SP142 showed strong concordance (k = 0.788) with combined+ rates of 33.3% (42/126) and 34.9% (44/126), respectively. In DLBCL‐NOS, TC+ by SP263 preferred to non‐GCB and immunoblastic variant DLBCL‐NOS (P = 0.029 and P = 0.004). Combined+ (SP263 and SP142) were associated with more than one extranodal site involved (P = 0.006, P = 0.042), higher ECOG PS scores (P = 0.001, P

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare type of non-Hodgkin lymphoma that typically has a good response rate to first line chemotherapy regimens. There have been reports of successful chemotherapy, but with a residual mass from fibrosis. Here, we report the case of a 19-year-old primigravida presenting with cardiogenic shock and superior vena cava (SVC) syndrome at full term who was found to have a PMBCL. Following delivery via urgent cesarean section, she was put on veno-arterial extra corporeal membrane oxygenation (VA-ECMO) and once hemodynamically stable was started on chemotherapy. In view of limited change in tumor size on consecutive CT scans and questionable response to chemotherapy, there were multidisciplinary meetings wherein withdrawing support was discussed and put forward to the family. At that point, surgical debulking was offered on compassionate grounds to be able to wean her off the VA-ECMO. This case report highlights the role of salvage resection when there are no other options.

COVID-19 has become the biggest public health problem and one of the most important causes of death in many countries in the world. SARS-CoV-2 infection is most likely to be fatal in elderly patients with concomitant diseases. In this article we present two cases of asymptomatic SARS-CoV-2-positive patients suffering from cancer who were treated with chemotherapy. The first case, a patient with primary mediastinal B-cell lymphoma, shows that confirmed SARS-CoV-2 infection does not have to be a contraindication to chemotherapy. We describe the course of disease and discuss doubts related to the choice of chemotherapy regimen. The second patient was a male with metastatic sigmoid cancer treated with FOLFOX4 as first-line palliative chemotherapy. This case draws attention to asymptomatic SARS-CoV-2 carriers who underwent chemotherapy. Our patient was safely treated with chemotherapy without long break caused by viral infection. It should be remembered that there are asymptomatic carriers among cancer patients and that they may spread infection to others. On the other hand, delaying chemotherapy can cause rapid disease progression and reduce overall survival of our patients.

COVID-19 has become the biggest public health problem and one of the most important causes of death in many countries in the world. SARS-CoV-2 infection is most likely to be fatal in elderly patients with concomitant diseases. In this article we present two cases of asymptomatic SARS-CoV-2-positive patients suffering from cancer who were treated with chemotherapy. The first case, a patient with primary mediastinal B-cell lymphoma, shows that confirmed SARS-CoV-2 infection does not have to be a contraindication to chemotherapy. We describe the course of disease and discuss doubts related to the choice of chemotherapy regimen. The second patient was a male with metastatic sigmoid cancer treated with FOLFOX4 as first-line palliative chemotherapy. This case draws attention to asymptomatic SARS-CoV-2 carriers who underwent chemotherapy. Our patient was safely treated with chemotherapy without long break caused by viral infection. It should be remembered that there are asymptomatic carriers among cancer patients and that they may spread infection to others. On the other hand, delaying chemotherapy can cause rapid disease progression and reduce overall survival of our patients. [ABSTRACT FROM AUTHOR]

The expression of programmed cell death ligand 1 (PD‐L1) is a biomarker for immunotherapy, but approved detection method is absent in diffuse large B‐cell lymphoma (DLBCL). Here, we performed three methods including immunohistochemistry (IHC) (clone SP263 and SP142), RNAscope, and fluorescence in situ hybridization (FISH) to evaluate PD‐L1 status on a cohort of DLBCL including 94 of DLBCL‐NOS, 25 of primary mediastinal large B‐cell lymphoma (PMBCL) and 7 of double‐hit lymphoma (DHL). SP263 with 25% for immune cell (IC) or combined cell and SP142 with 10% for tumor cell (TC), 20% for both of IC and combined cell were proved to have corresponding survival prognostic. Combined+ showed comparable prognostic value with TC+ and IC+. SP263 and SP142 showed strong concordance (k = 0.788) with combined+ rates of 33.3% (42/126) and 34.9% (44/126), respectively. In DLBCL‐NOS, TC+ by SP263 preferred to non‐GCB and immunoblastic variant DLBCL‐NOS (P = 0.029 and P = 0.004). Combined+ (SP263 and SP142) were associated with more than one extranodal site involved (P = 0.006, P = 0.042), higher ECOG PS scores (P = 0.001, P < 0.001), high IPI risk (P = 0.012, P = 0.005), and poor treatment response (P = 0.095, P = 0.002). IC+ by SP263 and SP142 were both independent risk factors (P = 0.027, P = 0.037). 9p24.1 locus amplification and gain were identified in 4.3% and 7.6% DLBCL‐NOS and indicated shorter overall survival (P = 0.004). Positive rate of PD‐L1 by RNAscope was 36.5%, while no clinical significance shown. PD‐L1 positive rates were all higher in PMBCL and DHL than in DLBCL‐NOS by SP263, SP142, RNAscope, and FISH (P = 0.001, P < 0.001, P = 0.005 and P < 0.001, respectively). In conclusion, combined PD‐L1 expression by IHC was potentially reliable and convenient as a predicting biomarker. SP263 staining was easier to evaluate and recognized more PD‐L1‐stained cells, but SP142 presented a better prognostic indicator. FISH and RNAscope could be used as supplementary assays. PMBCL itself was a sensitive cohort for immunotherapy. [ABSTRACT FROM AUTHOR]

Prior to the introduction of rituximab, primary mediastinal B-cell lymphoma (PMBCL) had high rates of treatment failure with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), prompting the use of consolidative mediastinal radiation or more intensive chemotherapy regimens. Cure rates improved dramatically with rituximab, but mediastinal radiation was still commonly employed with R-CHOP. We performed a retrospective review of patients treated with R-CHOP alone without radiation for PMBCL. Of 43 patients with PMBCL, 16 received R-CHOP alone. High-risk factors included 56% with bulky disease, 75% with elevated LDH, 25% with SVC syndrome, and 13% with stage IV disease. Three-year progression-free survival (PFS) and overall survival (OS) were 93% and 100% respectively. These results suggest that R-CHOP alone has a high cure rate in PMBCL while avoiding the side effects of mediastinal radiation. [ABSTRACT FROM AUTHOR]

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare type of non-Hodgkin lymphoma that typically has a good response rate to first line chemotherapy regimens. There have been reports of successful chemotherapy, but with a residual mass from fibrosis. Here, we report the case of a 19-year-old primigravida presenting with cardiogenic shock and superior vena cava (SVC) syndrome at full term who was found to have a PMBCL. Following delivery via urgent cesarean section, she was put on veno-arterial extra corporeal membrane oxygenation (VA-ECMO) and once hemodynamically stable was started on chemotherapy. In view of limited change in tumor size on consecutive CT scans and questionable response to chemotherapy, there were multidisciplinary meetings wherein withdrawing support was discussed and put forward to the family. At that point, surgical debulking was offered on compassionate grounds to be able to wean her off the VA-ECMO. This case report highlights the role of salvage resection when there are no other options. [ABSTRACT FROM AUTHOR]

Highlights • Outcomes of relapsed primary mediastinal large B cell lymphoma are uncharacterized. • We reviewed patients treated with second-line treatment and intent to transplant. • Our data suggest that this strategy is curative in most patients. • A risk score identified patients less likely to be cured with this strategy. Abstract Primary mediastinal (thymic) large B cell lymphoma is a subtype of diffuse large B cell lymphoma with distinct clinical, molecular, and genetic features, many of which overlap with Hodgkin lymphoma. Increasingly, initial therapy for these patients has used dose-dense chemotherapy with or without radiation with excellent results. In patients with relapsed and primary refractory disease, outcomes of second-line therapy followed by consolidation with high-dose therapy and autologous stem cell transplantation remains largely undefined. We reviewed the outcomes of 60 transplant-eligible patients with relapsed or refractory primary mediastinal (thymic) large B cell lymphoma enrolled on sequential protocols with uniform second-line therapy with intent to consolidate with autologous stem cell transplant. The estimated 3-year overall and event-free survivals for all patients were 61% and 57%, respectively, and 68% and 65%, respectively, for patients proceeding to stem cell transplant. Multivariable analysis of risk factors before transplant revealed that an incomplete response to initial therapy, advanced Ann Arbor stage at disease progression, and failure to achieve a partial remission or better to second-line therapy to be independently associated with inferior event-free and overall survival. A risk score based on these variables was able to identify patients who are unlikely to respond to conventional second-line strategies. These results suggest that salvage chemoradiotherapy with intent of subsequent high-dose therapy and autologous stem cell transplant is successful in most patients with relapsed and refractory primary mediastinal (thymic) large B cell lymphoma. Alternative strategies are warranted for a significant subset of patients with high-risk disease who are unlikely to be cured with this strategy. [ABSTRACT FROM AUTHOR]

Summary: Primary mediastinal (thymic) large B‐cell lymphoma (PMBCL) is an uncommon subtype of non‐Hodgkin lymphoma (NHL) that presents with a mediastinal mass and has unique clinicopathological features. Historically, patients with PMBCL were treated with R‐CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy ± involved field radiation. Since a phase II trial, published in April 2013, demonstrated excellent results using dose‐adjusted (DA) R‐EPOCH (rituximab, etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin), this treatment has gained popularity. We performed a retrospective, multicentre analysis of patients aged ≥18 years with PMBCL since January 2011. Patients were stratified by frontline regimen, R‐CHOP versus DA‐R‐EPOCH. 132 patients were identified from 11 contributing centres (56 R‐CHOP and 76 DA‐R‐EPOCH). The primary outcome was overall survival. Secondary outcomes included progression‐free survival, complete response (CR) rate, and rates of treatment‐related complications. Demographic characteristics were similar in both groups. DA‐R‐EPOCH use increased after April 2013 (79% vs. 45%, P < 0·001), and there was less radiation use after DA‐R‐EPOCH (13% vs. 59%, P < 0·001). While CR rates were higher with DA‐R‐EPOCH (84% vs. 70%, P = 0·046), these patients were more likely to experience treatment‐related toxicities. At 2 years, 89% of R‐CHOP patients and 91% of DA‐R‐EPOCH patients were alive. To our knowledge, this represents the largest series comparing outcomes of R‐CHOP to DA‐R‐EPOCH for PMBCL. [ABSTRACT FROM AUTHOR]

The optimal therapy for primary mediastinal B-cell lymphoma is a subject of ongoing debate, with no accepted standard of care. We performed a retrospective analysis of 63 patients in the modern era treated with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP), with or without radiation. Median age was 37 years (range 20-82). Eighty percent had limited stage disease and 71% were bulky. By age-adjusted International Prognostic Index (IPI), 15% were low-risk, 52% low-intermediate, 27% high-intermediate and 6% high-risk. Some 77% of responding patients received consolidative radiotherapy. Overall and complete response rates were 79% and 71%. Primary induction failure occurred in 13 (21%) patients. Five-year PFS and OS were 68% and 79%, respectively. Adverse prognostic features included increased IPI, advanced stage, advanced age and multiple extranodal sites. These data demonstrate an unacceptably high rate of primary refractory disease on R-CHOP, particularly among patients with high-risk features. Novel treatment approaches are needed that reduce primary refractory disease and reliance on mediastinal radiation in young people. [ABSTRACT FROM AUTHOR]

Summary: The physiologic expression of the product of the proto-oncogene TCL1 (T-cell leukemia 1) is primarily restricted to early embryonic cells. In nonneoplastic B cells, the expression of TCL1 is determined by the differentiation step with silencing at the germinal center stage. TCL1 protein is overexpressed in a wide variety of human diseases. It has been shown that TCL1 is a powerful B-cell oncogene, which has been implicated in the pathogenesis of various types of mature B-cell lymphomas. There is no comparative information in the literature addressing the expression of TCL1 in pediatric and adult nodal diffuse large B-cell lymphoma or primary mediastinal large B-cell lymphoma. We studied 55 cases of adult and pediatric diffuse large B-cell lymphoma and primary mediastinal large B-cell lymphoma to analyze the phenotypic profile of these lymphomas, including TCL1 expression, and its relationship with clinical outcome in different age groups. The cases were analyzed by immunohistochemistry for the expression of TCL1, CD10, BCL-2, BCL-6, and MUM1. We also evaluated c-MYC translocation by fluorescence in situ hybridization. TCL1 was observed in 11 cases, 5 pediatric and 6 adult cases, all but one diffuse large B-cell lymphoma. Pediatric cases showed a significant association between TCL1 expression, high proliferative index, and presence of c-MYC translocation. TCL1 positivity was predominantly found in germinal center phenotype diffuse large B-cell lymphoma. Overall survival was worse in adult TCL1-positive cases than pediatric ones. Primary mediastinal large B-cell lymphomas infrequently expressed TCL1 in both age groups. [ABSTRACT FROM AUTHOR]

Patients with high-risk aggressive B-cell lymphoma exhibit poor survival after R-CHOP. More intensive regimens yield higher rates of remission but also of complication. We investigated all 401 patients < 70 years with high-risk (age-adjusted [aa] international prognostic index [IPI] ≥2, extranodal, or bulky) aggressive B-cell lymphoma hospitalized at Karolinska for urgent start of immunochemotherapy (129 R-Hyper-CVAD; 261 R-CHOP/R-CHOEP). Patients showed IPI 3-5 (70%), WHO PS ≥2 (49%), bulky disease (70%), extranodal (75%) and CNS (8%) involvement. Five-year overall/progression-free survival (OS/PFS) was better in patients who started R-Hyper-CVAD (84%/77%) compared with R-CHOP/R-CHOEP (66%/55%). Differences were independent in multivariable analysis, seen in all patient categories, and accentuated in extreme high-risk disease: R-Hyper-CVAD vs. R-CHOP/R-CHOEP showed 5-year PFS 69% vs.40% in aaIPI 3 and 88% vs. 38% in CNS involvement. For validation, survival was compared between the two Karolinska sites and calendar periods. Survival was superior 2006-2010 at the site that introduced R-Hyper-CVAD/R-MA 2006, identical at both sites 2011-2017 after the other site adopted R-Hyper-CVAD/R-MA 2011, and excellent 2018-2020 when R-Hyper-CVAD/R-MA use increased to 75% of patients. Despite considerable toxicity, also patients aged 61-69 years showed better survival with R-Hyper-CVAD/R-MA. This is the largest single-centre series of patients treated with R-Hyper-CVAD/R-MA, showing favourable outcome in high-risk aggressive B-cell lymphoma., Competing Interests: The authors declare that they have no competing interests., (© 2021 The Authors. eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.)

Purpose: Diagnosing primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is challenging because it is a clinicopathologic entity that shares characteristics with other lymphomas and lacks pathognomonic features. We sought to investigate the fidelity between a working diagnosis of PMBCL at our institution and the clinicopathologic criteria established within the 2017 World Health Organization (WHO) classification., Patients and Methods: Medical records and archived tissue of patients treated for stage I-II PMBCL from 1998 to 2018 were retrospectively reviewed for clinical and pathologic conformity with current WHO criteria. Disease was characterized as definitely PMBCL if all of the following were present: anterior mediastinal mass with or without lymph node involvement, no extranodal disease, B-cell antigen expression, Epstein-Barr virus negativity, and at least one supportive feature: female gender under age 40, bulky primary tumor, CD30 weakly positive, compartmentalizing alveolar fibrosis, lack of surface immunoglobulin expression, and MUM1 or CD23 positivity. Disease without supportive features or other pathologic findings more suggestive of other entities was characterized as equivocal for PMBCL. Lack of an anterior mediastinal mass, presence of distant lymph node involvement or extranodal disease, lack of B-cell antigen expression, or Epstein-Barr virus positivity were characterized as definitely not PMBCL. Clinical management and outcomes were also assessed., Results: Of 63 patients treated for presumed stage I-II PMBCL, 58 (92%) met the criteria for PMBCL. The most common reason for a discordant diagnosis was lack of an anterior mediastinal mass (n = 3). Two additional patients were characterized as having disease equivocal for PMBCL. In retrospect, one patient most likely had a mediastinal gray zone lymphoma due to CD15 positivity and another diffuse large B cell, not otherwise specified, at pathologic review. Five-year progression-free and overall survival were 67% (95% confidence interval, 54-77) and 81% (95% confidence interval, 68-89), respectively, for all patients., Conclusion: Despite the complexity of the clinicopathologic criteria of PMBCL, most patients (92%) who were treated for stage I-II PMBCL at our institution appear to have been accurately diagnosed., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background : Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is an uncommon subtype of diffuse large B-cell lymphoma. Approximately 10-30% of patients experience refractory or relapsed PMBCL (rrPMBCL) after first-line therapy. Data and treatment guidelines for rrPMBCL are scarce, and management is based on clinical experience. Methods : Two structured literature reviews were undertaken to determine the incidence, prevalence, and mortality rates associated with rrPMBCL, and to identify clinical practice guidelines and real-world patterns of care. Results : Epidemiology studies included reported lymphomas ( n = 1), non-Hodgkin lymphoma ( n = 1), lymphoid neoplasm ( n = 1), PMBCL ( n = 6), and rrPMBCL ( n = 1). Of 12 published treatment guidelines, only four provided recommendations for rrPMBCL. Sixteen studies provided data on real-world treatment patterns, but most were single-center studies with small patient numbers. Chemotherapy/immunochemotherapy, followed by high-dose treatment (HDT) and stem cell transplantation, was a mainstay of salvage therapy in most studies; real-world care generally followed treatment guidelines. Conclusions : Salvage chemotherapy (often with rituximab and radiotherapy), followed by HDT and stem cell transplantation, appears to be the standard real-world treatment for rrPMBCL. However, large prospective and retrospective studies are warranted to improve our knowledge of real-world treatment patterns.

Aberrant constitutive activation of Rel/NF-κB transcription factors is a hallmark of numerous cancers. Of the five Rel family members, c-Rel has the strongest direct links to tumorigenesis. c-Rel is the only member that can malignantly transform lymphoid cells in vitro. Furthermore, c-Rel is implicated in human B cell lymphoma through the frequent occurrence of REL gene locus gains and amplifications. In normal physiology, high c-Rel expression predominates in the hematopoietic lineage and a diverse range of stimuli can trigger enhanced expression and activation of c-Rel. Both expression and activation of c-Rel are tightly regulated on multiple levels, indicating the necessity to keep its functions under control. In this review we meta-analyze and integrate studies reporting gene locus aberrations to provide an overview on the frequency of REL gains in human B cell lymphoma subtypes, namely follicular lymphoma, diffuse large B cell lymphoma, primary mediastinal B cell lymphoma, and classical Hodgkin lymphoma. We also summarize current knowledge on c-Rel expression and protein localization in these human B cell lymphomas and discuss the co-amplification of BCL11A with REL. In addition, we highlight and illustrate key pathways of c-Rel activation and regulation with a specific focus on B cell biology. [ABSTRACT FROM AUTHOR]