Variant ALK-fusion positive anaplastic large cell lymphoma (ALCL): A population-based paediatric study of the NHL-BFM study group

Frequency, distribution and prognostic meaning of ALK-partner genes other than NPM1 in ALK-positive anaplastic large-cell lymphoma (ALCL) are unknown. Forty-nine of 316 ALCL diagnosed in the NHL-BFM study group showed no nuclear ALK expression suggestive of a variant ALK-partner; 41 were analysed by genomic capture high-throughput sequencing or specific RT-PCRs. NPM1::ALK was detected in 13 cases. Among the 28 patients with a non-NPM1::ALK-fusion partner, ATIC (n = 8; 29%) and TPM3 (n = 9; 32%) were the most common. Five of eight patients with ATIC::ALK-positive ALCL relapsed, none of nine with TPM3::ALK. Variant ALK-partners are rare and potentially associated with different prognoses.

Improving outcomes of childhood and young adult non-Hodgkin lymphoma: 25 years of research and collaboration within the framework of the European Intergroup for Childhood Non-Hodgkin Lymphoma

The European Intergroup for Childhood Non-Hodgkin Lymphoma (EICNHL) was established 25 years ago with the goal to facilitate clinical trials and research collaborations in the field both within Europe and worldwide. Since its inception, much progress has been made whereby major improvements in outcomes have been achieved. In this Review, we describe the different diagnostic entities of non-Hodgkin lymphoma in children and young adults describing key features of each entity and outlining clinical achievements made in the context of the EICNHL framework. Furthermore, we provide an overview of advances in biopathology with an emphasis on the role of biological studies and how they have shaped available treatments. Finally, for each entity, we describe future goals, upcoming clinical trials, and highlight areas of research that require our focus going forward.

Diagnosis and management of ALK-positive anaplastic large cell lymphoma in children and adolescents

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) is a CD30-positive T cell lymphoma characterized by signalling from constitutively activated ALK fusion proteins. Most children and adolescents present in advanced stages, often with extranodal disease and B symptoms. The current front-line therapy standard of six cycles polychemotherapy reaches an event-free survival of 70%. The strongest independent prognostic factors are minimal disseminated disease and early minimal residual disease. At relapse, ALK-inhibitors, Brentuximab Vedotin, Vinblastine, or second line chemotherapy are effective re-inductions. Survival at relapse exceeds 60-70% with consolidation according to the time of relapse (Vinblastine monotherapy or allogeneic hematopoietic stem cell transplantation) so that the overall survival reaches 95%. It needs to be shown whether check-point inhibitors or long-term ALK-inhibition may substitute for transplantation. The future necessitates international cooperative trials testing whether a shift of paradigm to a chemotherapy-free regimen can cure ALK-positive ALCL.

Impact of COVID-19 Related Restrictions on Infections in Children with Cancer or after Hematopoietic SCTA

BACKGROUND

Infections are a major concern for immunocompromised children. We investigated whether non-pharmaceutical interventions (NPIs) implemented in the general population during the coronavirus disease 2019 (COVID-19) pandemic in Germany had an impact on frequency, type and severity of infections in these patients.

PATIENTS AND METHODS

We analyzed all admissions to the clinic of pediatric hematology, oncology and stem cell transplantation (SCT) with (suspected) infection or fever of unknown origin (FUO) from 2018 to 2021.

RESULTS

We compared a 27-month period before NPIs (Pre-COVID: 01/2018-03/2020; 1041 cases) with a 12-month period with underlying NPIs (COVID: 04/2020-03/2021; 420 cases). During the COVID period the number of in-patient stays with FUO or infections decreased (38,6 cases/month vs. 35,0 cases/month), the median duration of hospital stays was longer (8 d (CI95: 7-8 d) vs. 9 d (CI95: 8-10 d) P=0,02)), the mean number of antibiotics per case increased (2,1 (CI95: 2,0-2,2) vs. 2,5 (CI95: 2,3-2,7); P=0,003)) and a substantial reduction of viral respiratory and gastrointestinal infections per case was seen (0,24 vs. 0,13; P<0,001). Notably, there was no detection of respiratory syncytial virus, influenza and norovirus, between May 2020 and March 2021. Based on need of intensive care measures and further parameters we conclude that severe (bacterial) infections were not significantly reduced by NPIs.

CONCLUSIONS

Introduction of NPIs in the general population during the COVID-pandemic substantially reduced viral respiratory and gastrointestinal infections in immunocompromised patients, while severe (bacterial) infections were not prevented.

Automated production of specific T cells for treatment of refractory viral infections after allogeneic stem cell transplantation

Therapy resistant viral reactivations significantly contribute to mortality after hematopoietic stem cell transplantation. Adoptive cellular therapy with virus-specific T cells has shown efficacy in various single center trials. However, scalability of this therapy is hampered by laborious production methods. In this study we describe the in-house production of virus-specific T cells (VST) in a closed system (CliniMACS Prodigy® system by Miltenyi Biotec). In addition, we report the efficacy in 26 patients with viral disease post HSCT in a retrospective analysis (ADV n=7, CMV n=8, EBV n=4, multi-viral n=7). Production of VST was successful in 100% of cases. Safety profile of VST therapy was favorable (n=2 adverse event grade 3, n=1 grade 4; all three were reversible). A response was seen in 20 of 26 patients (77%). Responding patients had a significantly better OS than patients without response (p.

PDGFRβ promotes oncogenic progression via STAT3/STAT5 hyperactivation in anaplastic large cell lymphoma

BACKGROUND

Anaplastic large cell lymphoma (ALCL) is an aggressive non-Hodgkin T cell lymphoma commonly driven by NPM-ALK. AP-1 transcription factors, cJUN and JUNb, act as downstream effectors of NPM-ALK and transcriptionally regulate PDGFRβ. Blocking PDGFRβ kinase activity with imatinib effectively reduces tumor burden and prolongs survival, although the downstream molecular mechanisms remain elusive.

METHODS AND RESULTS

In a transgenic mouse model that mimics PDGFRβ-driven human ALCL in vivo, we identify PDGFRβ as a driver of aggressive tumor growth. Mechanistically, PDGFRβ induces the pro-survival factor Bcl-xL and the growth-enhancing cytokine IL-10 via STAT5 activation. CRISPR/Cas9 deletion of both STAT5 gene products, STAT5A and STAT5B, results in the significant impairment of cell viability compared to deletion of STAT5A, STAT5B or STAT3 alone. Moreover, combined blockade of STAT3/5 activity with a selective SH2 domain inhibitor, AC-4-130, effectively obstructs tumor development in vivo.

CONCLUSIONS

We therefore propose PDGFRβ as a novel biomarker and introduce PDGFRβ-STAT3/5 signaling as an important axis in aggressive ALCL. Furthermore, we suggest that inhibition of PDGFRβ or STAT3/5 improve existing therapies for both previously untreated and relapsed/refractory ALK+ ALCL patients.

Clinical relevance of molecular characteristics in Burkitt lymphoma differs according to age

While survival has improved for Burkitt lymphoma patients, potential differences in outcome between pediatric and adult patients remain unclear. In both age groups, survival remains poor at relapse. Therefore, we conducted a comparative study in a large pediatric cohort, including 191 cases and 97 samples from adults. While TP53 and CCND3 mutation frequencies are not age related, samples from pediatric patients showed a higher frequency of mutations in ID3, DDX3X, ARID1A and SMARCA4, while several genes such as BCL2 and YY1AP1 are almost exclusively mutated in adult patients. An unbiased analysis reveals a transition of the mutational profile between 25 and 40 years of age. Survival analysis in the pediatric cohort confirms that TP53 mutations are significantly associated with higher incidence of relapse (25 ± 4% versus 6 ± 2%, p-value 0.0002). This identifies a promising molecular marker for relapse incidence in pediatric BL which will be used in future clinical trials.

NFB-13. Rhabdoid Tumor Predisposition Syndrome (RTPS) – Finding Evidence by systematic Analyses

BACKGROUND: Individuals with rhabdoid tumor predisposition syndrome (RTPS1 – SMARCB1, RTPS2 – SMARCA4) have a propensity to develop malignant rhabdoid tumors (MRT). Affected patients typically present &lt; age 12 months with synchronous tumors (SYN) exhibiting an unusually aggressive clinical behavior. Due to the rarity of RTPS, standards for management are evolving. METHODS: Clinical, genetic, and treatment data of 90 patients with RTPS from 16 countries were analyzed (2004 – 2020). Therapy followed the EU-RHAB recommendations. Tumors and matching blood samples were investigated for SMARCB1 and/or SMARCA4 mutations using FISH, MLPA and sequencing. DNA-methylation subgroups were determined using DNA methylation arrays. RESULTS: The median age at diagnosis of 52 girls and 38 boys was 5.5 months (0 – 203). 55.5% (50/90) of patients presented with an atypical teratoid/rhabdoid tumor (ATRT), 23.5% (21/90) demonstrated SYN, and 21% (19/90) extracranial MRT. RTPS1 was present in 84-, RTPS2 in six patients. In 77% (65/84) complete data on SMARCB1 mutational status were generated. Methylation subgroup status was available in 59% (40/68) of ATRT or SYN. The 5-year overall- (OS) and event free survival rates of patients with RTPS1 were 19.8 ± 4.8% and 15 ± 4.2%, respectively. Age &lt; 1 year at diagnosis (10.1±4.3% vs. 46.7±11.1%), presence of SYN (5.3±5.1% vs. 24.8±6%), histological diagnosis (ATRT vs. eMRT/RTK/SYN) (26.8±7.1% vs. 11.9±5.6%), localized disease (34.5±8 vs. 8.3±4.6%), and presence of PGV at C-terminal (33±8.6% vs. 9.4±5.3%) were significant prognostic factors for 5-year OS in univariate analysis. INTERPRETATION: In the largest cohort of patients with RTPS, predictors significant for positive outcome could be detected: age &gt; 1 year, absence of SYN, histological diagnosis ATRT, localized disease and PGV located at C-terminal. In our research project, we aim to characterize the complete pheno- and genotype of patients with RTPS to develop a risk score including surveillance recommendation.

Molecular features of non-anaplastic peripheral T-cell lymphoma in children and adolescents

Non-anaplasticperipheral T-cell lymphomas (PTCL) are rare tumors in children, adolescents, and young adults (CAYA) with poor prognosis and scarce genetic data. We analyzed lymphoma tissue from 36 patients up to 18 years old with PTCL, not otherwise specified (PTCL-NOS), hepatosplenic T-cell lymphoma, Epstein-Barr virus (EBV)-positive T-lymphoproliferative diseases, subcutaneous panniculitis-like T-cell lymphoma, and other PTCL types. Twenty-three patients (64%) had at least one genetic variant detectable, including TET2, KMT2C, PIK3D, and DMNT3A. TP53 and RHOA variants, commonly found in adults, were not identified. Eight of 20 (40%) CAYA PTCL-NOS had no detectable mutations. The genetic findings suggest that CAYA PTCL differ from adult cases.

Super-enhancer-based identification of a BATF3/IL-2R-module reveals vulnerabilities in anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL), an aggressive CD30-positive T-cell lymphoma, comprises systemic anaplastic lymphoma kinase (ALK)-positive, and ALK-negative, primary cutaneous and breast implant-associated ALCL. Prognosis of some ALCL subgroups is still unsatisfactory, and already in second line effective treatment options are lacking. To identify genes defining ALCL cell state and dependencies, we here characterize super-enhancer regions by genome-wide H3K27ac ChIP-seq. In addition to known ALCL key regulators, the AP-1-member BATF3 and IL-2 receptor (IL2R)-components are among the top hits. Specific and high-level IL2R expression in ALCL correlates with BATF3 expression. Confirming a regulatory link, IL-2R-expression decreases following BATF3 knockout, and BATF3 is recruited to IL2R regulatory regions. Functionally, IL-2, IL-15 and Neo-2/15, a hyper-stable IL-2/IL-15 mimic, accelerate ALCL growth and activate STAT1, STAT5 and ERK1/2. In line, strong IL-2Rα-expression in ALCL patients is linked to more aggressive clinical presentation. Finally, an IL-2Rα-targeting antibody-drug conjugate efficiently kills ALCL cells in vitro and in vivo. Our results highlight the importance of the BATF3/IL-2R-module for ALCL biology and identify IL-2Rα-targeting as a promising treatment strategy for ALCL.

Anaplastic large cell lymphoma (ALCL) is an aggressive T-cell lymphoma often with poor prognosis. To identify genes defining ALCL cell state and dependencies, the authors here characterize ALCL-specific super-enhancers and describe the BATF3/IL-2R−module as a therapeutic opportunity for ALCL.

Dose-adjusted EPOCH-Rituximab or intensified B-NHL therapy for pediatric primary mediastinal large B-cell lymphoma

Not available.

Whole Exome Sequencing reveals NOTCH1 mutations in anaplastic large cell lymphoma and points to Notch both as a key pathway and a potential therapeutic target

Patients diagnosed with Anaplastic Large Cell Lymphoma (ALCL) are still treated with toxic multi-agent chemotherapy and as many as 25-50% of patients relapse. To understand disease pathology and to uncover novel targets for therapy, Whole-Exome Sequencing (WES) of Anaplastic Lymphoma Kinase (ALK)+ ALCL was performed as well as Gene-Set Enrichment Analysis. This revealed that the T-cell receptor (TCR) and Notch pathways were the most enriched in mutations. In particular, variant T349P of NOTCH1, which confers a growth advantage to cells in which it is expressed, was detected in 12% of ALK+ and ALK- ALCL patient samples. Furthermore, we demonstrate that NPM-ALK promotes NOTCH1 expression through binding of STAT3 upstream of NOTCH1. Moreover, inhibition of NOTCH1 with γ-secretase inhibitors (GSIs) or silencing by shRNA leads to apoptosis; co-treatment in vitro with the ALK inhibitor Crizotinib led to additive/synergistic anti-tumour activity suggesting this may be an appropriate combination therapy for future use in the circumvention of ALK inhibitor resistance. Indeed, Crizotinib-resistant and sensitive ALCL were equally sensitive to GSIs. In conclusion, we show a variant in the extracellular domain of NOTCH1 that provides a growth advantage to cells and confirm the suitability of the Notch pathway as a second-line druggable target in ALK+ ALCL.

Second malignancies after treatment of childhood non-Hodgkin lymphoma: a report of the Berlin-Frankfurt-Muenster study group

Second malignant neoplasms pose a concern for survivors of childhood cancer. We evaluated incidence, type and risk factors for second malignant neoplasms in patients included in Berlin-Frankfurt-Muenster protocols for childhood non-Hodgkin lymphoma. 3590 patients <15 years of age at diagnosis registered between 01/1981 and 06/2010 were analyzed. Second malignant neoplasms were reported by the treating institutions and the German Childhood Cancer Registry. After median follow-up of 9.4 years (Quartile, Q1 6.7 and Q3 12.1) 95 second malignant neoplasms were registered (26 carcinomas including 9 basal cell carcinomas, 21 acute myeloid leukemias/myelodysplastic syndromes, 20 lymphoid malignancies, 12 CNS-tumors, and 16 other). Cumulative incidence at 20 years was 5.7±0.7%, standard incidence ratio excluding basal cell carcinomas was 19.8 (95% CI 14.5-26.5). Median time from initial diagnosis to second malignancy was 8.7 years (range: 0.2-30.3). Acute-lymphoblastic-leukemia-type therapy, cumulative anthracycline dose, and cranial radiotherapy for brain tumor-development were significant risk factors in univariate analysis only. In multivariate analysis including risk factors significant in univariate analysis, female sex (HR 1.87, 95% CI 1.23-2.86, p=0.004), CNS-involvement (HR 2.24, 95% CI 1.03-4.88, p=0.042), lymphoblastic lymphoma (HR 2.60, 95% CI 1.69-3.97, p<0.001), and cancer-predisposing condition (HR 11.2, 95% CI 5.52-22.75, p<0.001) retained an independent risk. Carcinomas were the most frequent second malignant neoplasms after non-Hodgkin lymphoma in childhood followed by acute myeloid leukemia and lymphoid malignancies. Female sex, lymphoblastic lymphoma, CNS-involvement, or/and known cancer-predisposing condition were risk factors for second malignant neoplasm-development. Our findings set the basis for individualized long-term follow-up and risk assessment of new therapies.

Second malignant neoplasms after treatment of non-Hodgkin's lymphoma-a retrospective multinational study of 189 children and adolescents

Data on the spectrum of second malignant neoplasms (SMNs) after primary childhood non-Hodgkin's lymphoma (NHL) are scarce. One-hundred-and-eighty-nine NHL patients diagnosed in a 30 years period of 1980-2010 developing an SMN were retrieved from 19 members of the European Intergroup for Childhood NHL and/or the international Berlin-Frankfurt-Münster Study Group. Five subgroups of SMNs were identified: (1) myeloid neoplasms (n = 43; 23%), (2) lymphoid neoplasms (n = 51; 27%), (3) carcinomas (n = 48; 25%), (4) central nervous system (CNS) tumors (n = 19; 10%), and (5) "other" SMNs (n = 28; 15%). In 37 patients (20%) preexisting disorders were reported with 90% having any kind of cancer predisposition syndrome (CPS). For the 189 primary NHL patients, 5-year overall survival (OS) after diagnosis of an SMN was 56 ± 4%, being worst for patients with preexisting disorders at 28 ± 8%. Five-year OS rates were 38 ± 8%, 59 ± 7%, 79 ± 8%, 34 ± 12%, and 62 ± 11%, respectively, for patients with myeloid and lymphoid neoplasms, carcinomas, CNS tumors, and "other" SMNs (p < 0.0001). Patients with SMNs after childhood NHL having a reported CPS, mostly mismatch repair disorders, carried a very poor prognosis. Moreover, although outcome was favorable in some subtypes of SMNs after childhood NHL (carcinomas, lymphoid neoplasms), other SMNs such as myeloid neoplasms and CNS tumors had a dismal prognosis.

Stem Cell Transplantation and Vinblastine Monotherapy for Relapsed Pediatric Anaplastic Large Cell Lymphoma: Results of the International, Prospective ALCL-Relapse Trial

PURPOSE

To analyze the efficacy of a risk-stratified treatment of children with relapsed anaplastic large cell lymphoma (ALCL). The ALCL-Relapse trial (ClinicalTrials.gov identifier: NCT00317408 ) stratified patients according to the time of relapse and CD3 expression to prospectively test reinduction approaches combined with consolidation by allogeneic or autologous hematopoietic stem cell transplantation (SCT) and vinblastine monotherapy.

PATIENTS AND METHODS

Patients with progression during frontline therapy (very high risk) or a CD3-positive relapse (high risk) were scheduled for allogeneic SCT after reinduction chemotherapy. Patients with a CD3-negative relapse within 1 year after initial diagnosis or prior exposure to vinblastine (intermediate risk) received autologous SCT after carmustine-etoposide-cytarabine-melphalan. This arm was terminated prematurely, and subsequent patients received vinblastine monotherapy instead. Patients with a CD3-negative relapse > 1 year after initial diagnosis (low risk) received vinblastine monotherapy.

RESULTS

One hundred sixteen patients met the inclusion criteria; 105 evaluable patients with CNS-negative disease had a 5-year event-free survival (EFS) of 53% ± 5% and a 5-year overall survival (OS) of 78% ± 4%. Before termination of autologous SCT, EFS rates of patients in the very-high- (n = 17), high- (n = 26), intermediate- (n = 32), and low- (n = 21) risk groups were 41% ± 12%, 62% ± 10%, 44% ± 9%, and 81% ± 9%; the respective OS rates were 59% ± 12%, 73% ± 9%, 78% ± 7%, and 90% ± 6%. Analyzing only the patients in the intermediate-risk group consolidated per protocol by autologous SCT, EFS and OS of 23 patients were 30% ± 10% and 78% ± 9%, respectively. All 5 patients with intermediate risk receiving vinblastine monotherapy after the amendment experienced relapse again.

CONCLUSION

Shorter time to relapse was the strongest predictor of subsequent relapse. Allogeneic SCT offers a chance for cure in patients with high-risk ALCL relapse. For early relapsed ALCL autologous SCT was not effective. Vinblastine monotherapy achieved cure in patients with late relapse; however, it was not effective for early relapses.

Clinical and genetic risk factors define two risk groups of extracranial malignant rhabdoid tumours (eMRT/RTK)

INTRODUCTION

Extracranial rhabdoid tumours are rare, highly aggressive malignancies primarily affecting young children. The EU-RHAB registry was initiated in 2009 to prospectively collect data of rhabdoid tumour patients treated according to the EU-RHAB therapeutic framework.

METHODS

We evaluated 100 patients recruited within EU-RHAB (2009-2018). Tumours and matching blood samples were examined for SMARCB1 mutations by sequencing and cytogenetics.

RESULTS

A total of 70 patients presented with extracranial, extrarenal tumours (eMRT) and 30 with renal rhabdoid tumours (RTK). Nine patients demonstrated synchronous tumours. Distant metastases at diagnosis (M+) were present in 35% (35/100), localised disease (M0) with (LN+) and without (LN-) loco-regional lymph node involvement in 65% (65/100). SMARCB1 germline mutations (GLM) were detected in 21% (17/81 evaluable) of patients. The 5-year overall survival (OS) and event-free survival (EFS) rates were 45.8 ± 5.4% and 35.2 ± 5.1%, respectively. On univariate analyses, age at diagnosis (≥12 months), M0-stage, absence of synchronous tumours, absence of a GLM, gross total resection (GTR), radiotherapy and achieving a CR were significantly associated with favourable outcomes. In an adjusted multivariate model presence of a GLM, M+ and lack of a GTR were the strongest significant negative predictors of outcome.

CONCLUSIONS

We suggest to stratify patients with localised disease (M0), GTR+ and without proof of a GLM (5-year OS 72.2 ± 9.9%) as 'standard risk'. Patients presenting with one of the features M+ and/or GTR- and/or GLM+ belong to a high risk group (5-year, OS 32.5 ± 6.2%). These patients need novel therapeutic strategies such as combinations of targeted agents with conventional chemotherapy or novel experimental approaches ideally within international phase I/II trials.

Prognostic Factors in Childhood Anaplastic Large Cell Lymphoma: Long Term Results of the International ALCL99 Trial

With the aim of describing the long-term follow-up and to define the prognostic role of the clinical/pathological/molecular characteristics at diagnosis for childhood, adolescent and young adults affected by anaplastic large cell lymphoma (ALCL), we analyzed 420 patients aged up to 22 years homogeneously treated within the international ALCL99 trial. The 10-year progression free survival (PFS) was 70% and overall survival was 90%, rare late relapses occurred but no secondary malignancies were reported. Among clinical/pathological characteristics, only patients presenting a small cell/lymphohistiocytic (SC/LH) pattern were independently associated with risk of failure (hazard ratio = 2.49). Analysis of minimal disseminated disease (MDD), available for 162 patients, showed that both SC/LH pattern (hazard ratio = 2.4) and MDD positivity (hazard ratio = 2.15) were significantly associated with risk of failure in multivariate analysis. Considering MDD and SC/LH results, patients were separated into three biological/pathological (bp) risk groups: a high-risk group (bpHR) including MDD-positive patients with SC/LH pattern; a low-risk group (bpLR) including MDD-negative patients without SC/LH pattern; and an intermediate-risk group (bpIR) including remaining patients. The 10-year PFS was 40%, 75% and 86% for bpHR, bpIR and bpLR, respectively (p < 0.0001). These results should be considered in the design of future ALCL trials to tailor individual treatments.

Rare non-Hodgkin lymphoma of childhood and adolescence: A consensus diagnostic and therapeutic approach to pediatric-type follicular lymphoma, marginal zone lymphoma, and nonanaplastic peripheral T-cell lymphoma

Pediatric-type follicular (PTFL), marginal zone (MZL), and peripheral T-cell lymphoma (PTCL) account each for <2% of childhood non-Hodgkin lymphoma. We present clinical and histopathological features of PTFL, MZL, and few subtypes of PTCL and provide treatment recommendations. For localized PTFL and MZL, watchful waiting after complete resection is the therapy of choice. For PTCL, therapy is subtype-dependent and ranges from a block-like anaplastic large cell lymphoma (ALCL)-derived and, alternatively, leukemia-derived therapy in PTCL not otherwise specified and subcutaneous panniculitis-like T-cell lymphoma to a block-like mature B-NHL-derived or, preferentially, ALCL-derived treatment followed by hematopoietic stem cell transplantation in first remission in hepatosplenic and angioimmunoblastic T-cell lymphoma.

Neuro-meningeal relapse in anaplastic large-cell lymphoma: incidence, risk factors and prognosis - a report from the European intergroup for childhood non-Hodgkin lymphoma

Relapses involving the central nervous system (CNS) are rare in children and adolescents with ALK+ anaplastic large cell lymphoma (ALCL) treated with regimens including CNS prophylaxis. Early identification of patients at high-risk for CNS relapse would enable stratification and better adaptation of initial treatment especially in the light of the upcoming targeted therapies with limited CNS penetration. We analyzed clinical and histological data of all ALK+ALCL patients with CNS relapse registered in ALCL99-database with the aim to describe risk factors and outcome. Characteristics of patients with no relapse, relapse without CNS involvement and CNS relapse were compared. At a median follow-up of 8 years (0.05-18 years), a CNS involvement was reported at first or subsequent relapse in 26/618 patients. Median interval between initial diagnosis and first CNS relapse was 8 months (IQR 5.55-10.61/range 1.31-130.69). The 5-year cumulative risk of CNS relapse was 4% (95% CI 2.9-5.5). Bone marrow involvement, peripheral blasts and CNS involvement at diagnosis were more frequent in patients with CNS relapse than in patients with no relapse or with relapse with no CNS involvement. The treatment of CNS relapse was heterogeneous. The median survival after CNS relapse was 23.7 months. Eleven patients were alive at last follow-up. Three-year overall survival after CNS relapse was 48.70% (95% CI 30.52-67.23).

Experience with provisional WHO-entities large B-cell lymphoma with IRF4-rearrangement and Burkitt-like lymphoma with 11q aberration in paediatric patients of the NHL-BFM group

Large B-cell lymphoma with IRF4 rearrangement, and Burkitt-like lymphoma with 11q aberration are two provisional lymphoma entities in the 2017 revision of the WHO classification of lymphoid neoplasms. Despite being more frequent in young patients, knowledge regarding their true incidence and clinical features in unselected cohorts of paediatric and adolescent patients is limited. We screened for both entities among paediatric patients (<18 years of age) in the German NHL-BFM (Non-Hodgkin lymphoma Berlin-Frankfurt-Münster) group. Among follicular lymphomas and diffuse large B-cell lymphomas (DLBCL), 7/34 cases (21%) showed an IRF4 break-apart pattern by fluorescence in situ hybridisation (FISH) and are associated with stages I and II disease (P = 0·043). Among lymphomas morphologically resembling Burkitt lymphoma, DLBCL and high-grade B-cell lymphoma, unclassifiable, 13/102 cases (13%) lacked a MYC break-apart pattern but were positive for 11q proximal gain and telomeric loss by FISH. MYC-negative Burkitt-like lymphomas with the typical 11q gain-loss pattern by FISH were older (P = 0·004), showed less male predominance (P = 0·003), lower stage (P = 0·040), lower serum LDH level (P = 0·01) and less abdominal involvement (P = 0·008) compared to high grade B-cell lymphomas without 11q gain-loss pattern. Both entities showed excellent outcome with overall survival of 100% when managed according to NHL-BFM strategies and may provide candidates for future therapy de-escalation in clinical trials.

Tuberculosis-Associated HLH in an 8-Month-Old Infant: A Case Report and Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare immunological disease, which can be mistaken for sepsis easily. Among the infectious causes that may trigger secondary HLH, tuberculosis (TBC), a rather rare pathogen nowadays, is typical. To our knowledge, this is the first case report of an infant suffering from TBC-associated HLH-induced acute respiratory failure who was treated successfully using extracorporeal membrane oxygenation. An 8-month-old boy with fever (over the last 8 wk) and pancytopenia was transferred to our institution with acute respiratory failure and for extracorporeal membrane oxygenation therapy. Bone marrow biopsy revealed hemophagocytosis. Immunological work-up for familial HLH was negative. In a desperate search for the cause of secondary HLH, an interferon-gamma release assay for TBC returned positive. However, microscopy for acid-fast bacteria as well as polymerase chain reaction for TBC were initially negative. Despite this, the child was treated with tuberculostatic therapy. TBC was finally confirmed. The child remained on extracorporeal membrane oxygenation for 28 d. Further work-up showed typical lesions of disseminated TBC. The mother was identified as the source of TBC. The boy presents with mild sequelae (fine motor skills). In infants with suspected septicemia, TBC should be considered as differential diagnosis even if the results are initially negative.

Quantification of minimal disseminated disease by quantitative polymerase chain reaction and digital polymerase chain reaction for NPM-ALK as a prognostic factor in children with anaplastic large cell lymphoma

Detection of minimal disseminated disease is a validated prognostic factor in ALK-positive anaplastic large cell lymphoma. We previously reported that quantification of minimal disease by quantitative real-time polymerase chain reaction (RQ-PCR) in bone marrow applying a cut-off of 10 copies NPM-ALK/10⁴ copies of ABL1 identifies very high-risk patients. In the present study, we aimed to confirm the prognostic value of quantitative minimal disseminated disease evaluation and to validate digital polymerase chain reaction (dPCR) as an alternative method. Among 91 patients whose bone marrow was analyzed by RQ-PCR, more than 10 normalized copy-numbers correlated with stage III/IV disease, mediastinal and visceral organ involvement and low anti-ALK antibody titers. The cumulative incidence of relapses of 18 patients with more than 10 normalized copy-numbers of NPM-ALK was 61±12% compared to 21±5% for the remaining 73 patients (P=0.0002). Results in blood correlated with those in bone marrow (r=0.74) in 70 patients for whom both materials could be tested. Transcripts were quantified by RQ-PCR and dPCR in 75 bone marrow and 57 blood samples. Copy number estimates using dPCR and RQ-PCR correlated in 132 samples (r=0.85). Applying a cut-off of 30 copies NPM-ALK/10⁴ copies ABL1 for quantification by dPCR, almost identical groups of patients were separated as those separated by RQ-PCR. In summary, the prognostic impact of quantification of minimal disseminated disease in bone marrow could be confirmed for patients with anaplastic large cell lymphoma. Blood can substitute for bone marrow. Quantification of minimal disease by dPCR provides a promising tool to facilitate harmonization of minimal disease measurement between laboratories and for clinical studies.

Allogeneic hematopoietic stem cell transplantation from unrelated donors is associated with higher infection rates in children with acute lymphoblastic leukemia-A prospective international multicenter trial on behalf of the BFM-SG and the EBMT-PDWP

Severe infections (SI) significantly impact on non‐relapse mortality after hematopoietic stem cell transplantation (HSCT). We assessed 432 children and adolescents with acute lymphoblastic leukemia (ALL) after total body irradiation based myeloablative HSCT within the multicenter ALL‐BFM‐SCT 2003 trial for SI grade 3 or higher according to common terminology criteria for adverse events. A total 172 patients experienced at least one SI. Transplantation from matched unrelated donors (MUD) was associated with any type of SI in the pre‐engraftment period (hazard ratio [HR]: 2.57; P < .001), and with any SI between day +30 and + 100 (HR: 2.91; P = .011). Bacterial (HR: 2.24; P = .041) and fungal infections (HR: 4.06; P = .057) occurred more often in the pre‐engraftment phase and viral infections more often before day +30 (HR: 2.66; P = .007) or between day +30 and + 100 (HR: 3.89; P = .002) after HSCT from MUD as compared to matched sibling donors. Chronic GvHD was an independent risk factor for any type of SI after day +100 (HR: 2.57; P < .002). We conclude that allogeneic HSCT from MUD in children and adolescents with pediatric ALL is associated with higher infection rates, which seems attributable to an intensified GvHD prophylaxis including serotherapy and methotrexate.

NPM-ALK-reactive T-cell responses in children and adolescents with NPM-ALK positive anaplastic large cell lymphoma

The oncoantigen nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) induces cellular and humoral immune responses in patients with NPM-ALK-positive anaplastic large cell lymphoma (ALCL). We characterize the NPM-ALK-specific T-cell responses in a cohort of pediatric and adolescent ALCL-patients in remission without Human Leucocyte Antigen (HLA)-preselection.

First, we assessed NPM-ALK-reactive T-cell responses and their HLA-class I restriction in patients by using dendritic cells (DCs) transfected with in vitro transcribed (IVT) NPM-ALK-RNA for CD8 (n = 20) or CD3 (n = 9) T-cell stimulation. NPM-ALK-specific T-cells were detected in twelve of 29 patients (nine of 20 with CD8-selected and three of nine with CD3-selected cells). Recognition of NPM-ALK was restricted by HLA-C alleles in six of eight, and by HLA-B alleles in four of eight analyzed patients. No NPM-ALK-reactivity was detected in 20 healthy individuals.

Second, in order to define possible immunogenic NPM-ALK-epitope regions, DCs pulsed with pools of overlapping long NPM-ALK-peptides were used to stimulate T-cells in further 22 patients and ten controls. Responsive T-cells were detected in 15 patients and in five controls. A peptide pool located in the middle of the kinase domain induced ALK-reactive T-cells in 14 of 15 responsive patients. We could narrow to single peptides between p327-p370 of NPM-ALK in four patients.

In conclusion, using IVT-RNA, 40% of NPM-ALK-positive ALCL-patients in remission had detectable NPM-ALK-specific T-cell responses which were mainly restricted by HLA-B and -C alleles. Peptide stimulation of T-cells revealed responses in almost 70% of patients and allowed describing an immunogenic region located in the ALK-kinase domain.

Rare mature B-cell lymphomas in children and adolescents

Pediatric-type follicular lymphoma (PTFL), pediatric nodal marginal zone lymphoma (pnMZL), and large B-cell lymphoma (LBCL) with IRF4 rearrangement have been introduced into the current World Health Organization (WHO) classification. They account for 5% to 10% of mature B-cell lymphomas in children and adolescents. Both PTFL and pnMZL predominantly affect male adolescents and usually present with localized lymphadenopathy in the head and neck region. The cells within the follicles of PTFL typically show high-grade cytology, IGH monoclonality and lack the t(14;18) chromosomal alteration. In contrast, pnMZL is characterized by progressive transformation of germinal center (PTGC)-like features and interfollicular proliferation of the cells with expansion of the marginal zones with diffuse areas. Watch and wait after complete resection seems an adequate therapy with chemotherapy restricted to incompletely resected disease. All children with PTFL and pnMZL reported, so far, survived. B-cell lymphomas presenting in the Waldeyer's ring are characterized by the expression of IRF4/MUM1 and often associated with IRF4 rearrangements. Because of the frequent diffuse component, treatment often follows current protocols for mature B-NHL. The prognosis is excellent.

Hematopoietic Stem Cell Transplantation as Treatment for Patients with DOCK8 Deficiency

BACKGROUND

Biallelic variations in the dedicator of cytokinesis 8 (DOCK8) gene cause a combined immunodeficiency with eczema, recurrent bacterial and viral infections, and malignancy. Natural disease outcome is dismal, but allogeneic hematopoietic stem cell transplantation (HSCT) can cure the disease.

OBJECTIVE

To determine outcome of HSCT for DOCK8 deficiency and define possible outcome variables.

METHODS

We performed a retrospective study of the results of HSCT in a large international cohort of DOCK8-deficient patients.

RESULTS

We identified 81 patients from 22 centers transplanted at a median age of 9.7 years (range, 0.7-27.2 years) between 1995 and 2015. After median follow-up of 26 months (range, 3-135 months), 68 (84%) patients are alive. Severe acute (III-IV) or chronic graft versus host disease occurred in 11% and 10%, respectively. Causes of death were infections (n = 5), graft versus host disease (5), multiorgan failure (2), and preexistent lymphoma (1). Survival after matched related (n = 40) or unrelated (35) HSCT was 89% and 81%, respectively. Reduced-toxicity conditioning based on either treosulfan or reduced-dose busulfan resulted in superior survival compared with fully myeloablative busulfan-based regimens (97% vs 78%; P = .049). Ninety-six percent of patients younger than 8 years at HSCT survived, compared with 78% of those 8 years and older (P = .06). Of the 73 patients with chimerism data available, 65 (89%) had more than 90% donor T-cell chimerism at last follow-up. Not all disease manifestations responded equally well to HSCT: eczema, infections, and mollusca resolved quicker than food allergies or failure to thrive.

CONCLUSIONS

HSCT is curative in most DOCK8-deficient patients, confirming this approach as the treatment of choice. HSCT using a reduced-toxicity regimen may offer the best chance for survival.

Mini photopheresis for refractory chronic graft-versus-host disease in children and adolescents

BACKGROUND

Extracorporeal photopheresis (ECP) has been established to treat graft-versus-host disease. Our mini ECP technique (mini-ECP) allows for treatment of patients with GVHD and contraindications for classical ECP or low body weight. The safety and efficacy of applying ECP for the long-term treatment of chronic GVHD (cGVHD) have not been described.

STUDY DESIGN AND METHODS

A retrospective analysis of mini-ECP treatments for children and adolescents with cGVHD was performed. Mini-ECP with 100 to 200 mL of whole blood was used to treat 14 patients. The median age at the start of treatment was 7 years (range, 1-17 years), and median body weight was 20 kg (range, 8-53 kg). A total of 703 mini-ECP treatments was performed. The median number of treatments per patient was 35 (range, 8-129), and median treatment duration was 11 months (range, 1.4-28.5 months).

RESULTS

Mini-ECP was well tolerated. Four adverse events occurred in three patients, and two of them were related to the ECP procedure. Complete or partial responses were observed in 10 patients. Steroids were discontinued in seven patients and tapered in three others. Responses were seen in the skin, mouth, gastrointestinal tract, and eyes.

CONCLUSION

Mini-ECP represents a less invasive ECP alternative for low-body-weight patients with cGVHD and contraindications for apheresis.

Epitope mapping of anti-ALK antibodies in children with anaplastic large cell lymphoma

Patients with Nucleophosmin (NPM)-Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) mount ALK autoantibodies. The titer of these autoantibodies inversely correlates with the risk of relapse. The epitopes recognized by these autoantibodies in NPM-ALK might be associated with different ALK-antibody levels. We used overlapping peptide microarray technology to analyze epitope-binding to NPM-ALK by plasma or serum from 129 ALK-positive ALCL patients and 21 controls. Antibodies present in sera from ALCL patients bound to epitopes mainly in the C-terminal region of the ALK portion of NPM-ALK (amino acid positions 469-496, 561-588, 617-644). Patients with higher ALK antibody titers detected the epitope 561-588 more frequently as well as three further epitopes at the N-terminus of the kinase domain compared to patients with intermediate and low titers. These results identify new potential target epitopes for immunotherapy in ALK-positive ALCL. The methodology can be adapted for more reproducible analyses of tumor antigen detection.

Lmo2 expression defines tumor cell identity during T-cell leukemogenesis

The impact of LMO2 expression on cell lineage decisions during T‐cell leukemogenesis remains largely elusive. Using genetic lineage tracing, we have explored the potential of LMO2 in dictating a T‐cell malignant phenotype. We first initiated LMO2 expression in hematopoietic stem/progenitor cells and maintained its expression in all hematopoietic cells. These mice develop exclusively aggressive human‐like T‐ALL. In order to uncover a potential exclusive reprogramming effect of LMO2 in murine hematopoietic stem/progenitor cells, we next showed that transient LMO2 expression is sufficient for oncogenic function and induction of T‐ALL. The resulting T‐ALLs lacked LMO2 and its target‐gene expression, and histologically, transcriptionally, and genetically similar to human LMO2‐driven T‐ALL. We next found that during T‐ALL development, secondary genomic alterations take place within the thymus. However, the permissiveness for development of T‐ALL seems to be associated with wider windows of differentiation than previously appreciated. Restricted Cre‐mediated activation of Lmo2 at different stages of B‐cell development induces systematically and unexpectedly T‐ALL that closely resembled those of their natural counterparts. Together, these results provide a novel paradigm for the generation of tumor T cells through reprogramming in vivo and could be relevant to improve the response of T‐ALL to current therapies.

CNS progression during vinblastine or targeted therapies for high-risk relapsed ALK-positive anaplastic large cell lymphoma: A case series

Vinblastine and targeted therapies induce remissions in patients with relapsed or progressive anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL). Central nervous system (CNS) prophylaxis often is not included during re-induction in CNS-negative relapse patients. We report on five patients with progressive or early relapsed ALK-positive ALCL who developed CNS progression during re-induction with vinblastine, crizotinib, or brentuximab vedotin given for bridging to allogeneic blood stem cell transplantation. These observations suggest that CNS prophylaxis should be considered in ALCL patients suffering progression during initial therapy who receive re-induction using agents with limited CNS penetration.

Characterization and diagnostic application of genomic NPM-ALK fusion sequences in anaplastic large-cell lymphoma

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion genes resulting from the translocation t(2;5)(p23;q35) are present in almost 90% of childhood ALK-positive anaplastic large-cell lymphomas (ALCL). Detection and quantification of minimal disseminated disease (MDD) by measuring NPM-ALK fusion transcript levels in the blood provide independent prognostic parameters. Characterization of the genomic breakpoints provides insights into the pathogenesis of the translocation and allows for DNA-based minimal disease monitoring.

We designed a nested multiplex PCR assay for identification and characterization of genomic NPM-ALK fusion sequences in 45 pediatric ALCL-patients, and used the sequences for quantitative MDD monitoring. Breakpoint analysis indicates the involvement of inaccurate non-homologous end joining repair mechanisms in the formation of NPM-ALK fusions. Parallel quantification of RNA and DNA levels in the cellular fraction of 45 blood samples from eight patients with NPM-ALK-positive ALCL correlated, as did cell-free circulating NPM-ALK DNA copies in the plasma fraction of 37 blood samples. With genomic NPM-ALK fusion sequence quantification, plasma samples of ALCL patients become an additional source for MRD-assessment. Parallel quantification of NPM-ALK transcripts and fusion genes in ALCL cell lines treated with the ALK kinase inhibitor crizotinib illustrates the potential value of supplementary DNA-based quantification in particular clinical settings.

Immune Response against ALK in Children with ALK-Positive Anaplastic Large Cell Lymphoma

Patients with anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) mount a humoral and cellular immune response against ALK. More than 90% of children and adolescents with ALK-positive ALCL have detectable anti-ALK antibodies in serum or plasma, and the antibody titer inversely correlates with the risk of relapse. ALK-specific CD8 and CD4 T cell responses have been described in patients with ALK-positive ALCL. Vaccination with ALK DNA led to protection against lymphoma growth in a murine model. Collectively, these data suggest that the ALK-specific immune response is involved in the control of the disease. The characteristics of the humoral and cellular immune response against ALK as well as tumor immune escape mechanisms have been increasingly investigated. However, tumor and host factors contributing to the individual immune response against ALK are still largely unknown. Depending on the individual strength of the immune response and its determinants, individualized immunological approaches might be appropriate for the consolidation of ALCL patients. Strategies such as ALK vaccination could be effective for those with a pre-existing anti-tumor immunity, while an allogeneic blood stem cell transplantation or check-point inhibition could be effective for others.

Duodenocolonic Fistula As A Rare Complication of Intestinal Burkitt Lymphoma in a Three-Year-Old Boy

BACKGROUND

Burkitt lymphoma (BL) in children often presents with abdominal localization. Intestinal perforations have been described mainly during treatment. We report on a three-year-old patient with abdominal BL who was diagnosed with a duodenocolonic fistula.

CASE REPORT

A three-year-old boy presented with diarrhea, crampy abdominal pain, and a four-week history of loss of appetite and weight. Ultrasound and MRI detected a colonic tumor forming a duodenocolonic fistula which was verified by gastroduodenoscopy. A surgical biopsy revealed BL. The stage III BL with low LDH was treated with four courses of BFM-type short-pulse chemotherapy. After two courses of chemotherapy the patient developed a mechanic ileus. A segmental resection of a short segment of the colon at the right flexure carrying the residual tumor mass with cicatricial stenosis and fistula followed by colonic end to end anastomosis and covering of the fistula by omentum major were carried out without complication. 15 days after surgery, two additional courses of chemotherapy could be administrated and the boy is in ongoing remission and free of any symptoms with a follow-up interval of 18 months.

CONCLUSIONS

Duodeonocolonic fistula at presentation in a child with abdominal BL is extremely rare. Delayed surgery after size of the tumor bulk has been reduced by chemotherapy might represent a risk adapted approach. However, due to limited experience with duodenocolonic fistulas even in larger pediatric lymphoma trials any decision has to be based on the problems to be faced in individual cases.

The AP-1-BATF and -BATF3 module is essential for growth, survival and TH17/ILC3 skewing of anaplastic large cell lymphoma

Transcription factor AP-1 is constitutively activated and IRF4 drives growth and survival in ALK⁺ and ALK^- anaplastic large cell lymphoma (ALCL). Here we demonstrate high-level BATF and BATF3 expression in ALCL. Both BATFs bind classical AP-1 motifs and interact with in ALCL deregulated AP-1 factors. Together with IRF4, they co-occupy AP-1-IRF composite elements, differentiating ALCL from non-ALCL. Gene-specific inactivation of BATFs, or global AP-1 inhibition results in ALCL growth retardation and/or cell death in vitro and in vivo. Furthermore, the AP-1-BATF module establishes TH17/group 3 innate lymphoid cells (ILC3)-associated gene expression in ALCL cells, including marker genes such as AHR, IL17F, IL22, IL26, IL23R and RORγt. Elevated IL-17A and IL-17F levels were detected in a subset of children and adolescents with ALK⁺ ALCL. Furthermore, a comprehensive analysis of primary lymphoma data confirms TH17-, and in particular ILC3-skewing in ALCL compared with PTCL. Finally, pharmacological inhibition of RORC as single treatment leads to cell death in ALCL cell lines and, in combination with the ALK inhibitor crizotinib, enforces death induction in ALK⁺ ALCL. Our data highlight the crucial role of AP-1/BATFs in ALCL and lead to the concept that some ALCL might originate from ILC3.

Blood cytokine concentrations in pediatric patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma

Patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma often present with B-symptoms or hemophagocytosis and generate an anti-tumor immune response. Specific serum cytokine levels or profiles may reflect the tumor burden, non-specific immune stimulation by the tumor or differences in the strength of the patients’ anti-lymphoma immunity. We systematically correlated pretreatment concentrations of 25 cytokines with clinical and biological characteristics in a well-characterized cohort of 119 uniformly treated pediatric patients with anaplastic large cell lymphoma. Fifteen patients with anaplastic large cell lymphoma in remission and 11 patients with low-stage B-cell lymphoma served as controls. Concentrations of interleukin-9, interleukin-10, interleukin-17a, hepatocyte growth factor, soluble interleukin-2 receptor, and soluble CD30 were significantly higher in initial sera of patients than in the sera of subjects from both control groups, indicating an anaplastic large cell lymphoma-type cytokine signature. The levels of interleukin-6, interferon-γ, interferon γ-induced protein, and soluble interleukin-2 receptor correlated with the stage, initial general condition, minimal disseminated disease, anaplastic lymphoma kinase-antibody titers, and the risk of relapse among patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma. Only interleukin-6 showed an independent prognostic value in multivariate analyses. Pretreatment cytokine profiles in patients with anaplastic large cell lymphoma reflect a tumor signature as well as tumor burden and also differences in the strength of the patients’ immune response.

Results and conclusions of the European Intergroup EURO-LB02 trial in children and adolescents with lymphoblastic lymphoma

In the European Intergroup EURO-LB02 trial, children and adolescents with lymphoblastic lymphoma underwent the non-Hodgkin lymphoma Berlin-Frankfurt-Münster protocol without prophylactic cranial radiotherapy. The primary aims of this trial were to test whether replacing prednisone with dexamethasone during induction increases event-free survival in the subgroups with T-cell lymphoblastic lymphoma and whether therapy duration could be reduced from 24 to 18 months (factorial design, randomizations). These questions could not be answered due to premature closure of the trial. Here we report on the secondary aims of the trial: whether the results of the NHL-BFM90 study could be reproduced and evaluation of disease features and prognostic factors. Three hundred and nineteen patients (66 with precursor B-cell lymphoblastic lymphoma, 233 with T-cell lymphoblastic lymphoma, 12 with mixed phenotype, 8 not classifiable) were enrolled. In induction, 215 patients received prednisone and 104 patients received dexamethasone. The median follow-up was 6.8 years (range, 3.0–10.3). The 5-year event-free survival was 82±2% [12 toxic deaths, 5 secondary malignancies, 43 non-response/relapse (central nervous system n=9; all received prednisone during induction)]. The event-free survival rate was 80±5% for patients with precursor B-cell lymphoblastic lymphoma, 82±3% for those with T-cell lymphoblastic lymphoma, and 100% for patients with a mixed phenotype. During induction, significantly more grade III/IV toxicities were observed in patients receiving dexamethasone, resulting in significant treatment delays. The number of toxic deaths did not differ significantly. The only variable associated with outcome was performance status at diagnosis. The 90% event-free survival rate for patients with T-cell lymphoblastic lymphoma shown in study NHL-BFM90 was not replicated, mainly due to more toxic deaths and central nervous system relapses. Dexamethasone in induction may prevent central nervous system relapse more effectively than prednisone but produces a higher burden of toxicity. (#NCT00275106).