Summary
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.
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.
Non-Hodgkin lymphoma is the fourth most common malignancy in children, has an even higher incidence in adolescents, and is primarily represented by only a few histologic subtypes. Dramatic progress ...has been achieved, with survival rates exceeding 80%, in large part because of a better understanding of the biology of the different subtypes and national and international collaborations. Most patients with Burkitt lymphoma and diffuse large B-cell lymphoma are cured with short intensive pulse chemotherapy containing cyclophosphamide, cytarabine, and high-dose methotrexate. The benefit of the addition of rituximab has not been established except in the case of primary mediastinal B-cell lymphoma. Lymphoblastic lymphoma is treated with intensive, semi-continuous, longer leukemia-derived protocols. Relapses in B-cell and lymphoblastic lymphomas are rare and infrequently curable, even with intensive approaches. Event-free survival rates of approximately 75% have been achieved in anaplastic large-cell lymphomas with various regimens that generally include a short intensive B-like regimen. Immunity seems to play an important role in prognosis and needs further exploration to determine its therapeutic application. ALK inhibitor therapeutic approaches are currently under investigation. For all pediatric lymphomas, the intensity of induction/consolidation therapy correlates with acute toxicities, but because of low cumulative doses of anthracyclines and alkylating agents, minimal or no long-term toxicity is expected. Challenges that remain include defining the value of prognostic factors, such as early response on positron emission tomography/computed tomography and minimal disseminated and residual disease, using new biologic technologies to improve risk stratification, and developing innovative therapies, both in the first-line setting and for relapse.
The genetic hallmark of Burkitt lymphoma (BL) is the t(8;14)(q24;q32) and its variants leading to activation of the MYC oncogene. It is a matter of debate whether true BL without MYC translocation ...exists. Here, we identified 59 lymphomas concordantly called BL by 2 gene expression classifiers among 753 B-cell lymphomas. Only 2 (3%) of these 59 molecular BL lacked a MYC translocation, which both shared a peculiar pattern of chromosome 11q aberration characterized by interstitial gains including 11q23.2-q23.3 and telomeric losses of 11q24.1-qter. We extended our analysis to 17 MYC-negative high-grade B-cell lymphomas with a similar 11q aberration and showed this aberration to be recurrently associated with morphologic and clinical features of BL. The minimal region of gain was defined by high-level amplifications in 11q23.3 and associated with overexpression of genes including PAFAH1B2 on a transcriptional and protein level. The recurrent region of loss contained a focal homozygous deletion in 11q24.2-q24.3 including the ETS1 gene, which was shown to be mutated in 4 of 16 investigated cases. These findings indicate the existence of a molecularly distinct subset of B-cell lymphomas reminiscent of BL, which is characterized by deregulation of genes in 11q.
•A subset of lymphomas with gene expression and pathological characteristics of Burkitt lymphomas but absence of MYC translocation does exist.•These lymphomas carry chr 11q proximal gains and telomeric losses, suggesting co-deregulation of oncogenes and tumor suppressor genes.
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
10
copies of
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
was 61±12% compared to 21±5% for the remaining 73 patients (
=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
/10
copies
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.
Minimal residual disease (MRD) detection is established routine practice for treatment stratification in leukemia and used for treatment optimization in adult lymphomas. Minimal disease studies in ...childhood non-Hodgkin lymphomas are challenged by stratified treatment in different subtypes, high cure rates, low patient numbers, limited initial tumor material, and early progression. Current clinical applications differ between the subtypes. A prognostic value of minimal disseminated disease (MDD) could not yet be clearly established for lymphoblastic lymphoma using flow cytometry and PCR-based methods for T-cell receptor (TCR) or immunoglobulin (IG) rearrangements.
fusion sequences or IG rearrangements enable minimal disease detection in Burkitt lymphoma and -leukemia. An additional prognostic value of MDD in Burkitt lymphoma and early MRD in Burkitt leukemia is implicated by single studies with risk-adapted therapy. MDD and MRD determined by PCR for ALK-fusion transcripts are independent prognostic parameters for patients with ALK-positive anaplastic large cell lymphoma (ALCL). They are introduced in routine clinical practice and used for patient stratification in clinical studies. Early MRD might serve as an endpoint for clinical trials and for guiding individual therapy. Validation of MDD and MRD as prognostic parameters is required for all subtypes but ALCL. Next-generation sequencing-based methods may provide new options and applications for minimal disease evaluation in childhood lymphomas.
Summary
Anaplastic large cell lymphomas (ALCL) in children express anaplastic lymphoma kinase (ALK) fusion genes, most commonly NPM1‐ALK. The distribution of X‐ALK among 66 childhood ALCLs was ...analysed. One ALCL was ALK‐negative. Reverse transcription polymerase chain reaction detected NPM1‐ALK in 58 tumours, all showing nuclear and cytoplasmic ALK staining. The remaining seven ALCL stained for ALK in the cytoplasm only: two expressed TPM3‐ALK, one ATIC‐ALK, one MYH9‐ALK; three no TPM3‐, TFG‐, ATIC‐, CLTC‐ or MYH9‐ALK. Almost 90% of paediatric ALK‐positive ALCLs express NPM1‐ALK. There was complete concordance between ALK staining pattern and the presence of a typical/variant ALK fusion partner.
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