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B cell progenitor acute lymphoblastic leukemia (BCP-ALL) is the most common childhood malignancy, driven by multiple genetic alterations that cause maturation arrest and accumulation of abnormal progenitor B cells. Current treatment protocols with chemotherapy have led to favorable outcomes but are associated with significant toxicity and risk of side effects, highlighting the necessity for highly effective, less toxic, targeted drugs, even in subtypes with a favorable outcome. Here, we used multimodal single-cell sequencing to delineate the transcriptional, epigenetic, and immunophenotypic characteristics of 23 childhood BCP-ALLs, belonging to the BCR::ABL1-positive, ETV6::RUNX1-positive, high hyperdiploid, and recently discovered DUX4-rearranged (DUX4-r) subtypes. Projection of the ALL cells along the normal hematopoietic differentiation axis revealed a diversity in the maturation pattern between the different BCP-ALL subtypes. Whereas the BCR::ABL1-, ETV6::RUNX1-positive, and high hyperdiploidy cells mainly showed similarities to normal pro-B cells, the DUX4-r ALL cells also displayed transcriptional signatures resembling mature B cells. Focusing on the DUX4-r subtype, we found that the blast population displayed multilineage priming toward non-hematopoietic cells, myeloid, and T cell lineages, but also an activation of PI3K/AKT signaling that sensitized the cells to PI3K inhibition in vivo. Given the multilineage priming of the DUX4-r blasts with aberrant expression of the myeloid marker CD371 (CLL-1), we generated chimeric antigen receptor T cells, which effectively eliminated DUX4-r ALL cells in vivo. These results provide a detailed characterization of BCP-ALL at the single-cell level and reveal therapeutic vulnerabilities in the DUX4-r subtype with implications for the understanding of ALL biology and new therapeutic strategies.
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Constitutional polymorphisms in ARID5B are associated with an increased risk of developing high hyperdiploid (HeH; 51-67 chromosomes) pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL). Here, we investigated constitutional and somatic ARID5B variants in 1335 BCP ALL cases from five different cohorts, with a particular focus on HeH cases. In 353 HeH ALL that were heterozygous for risk alleles and trisomic for chromosome 10, where ARID5B is located, a significantly higher proportion of risk allele duplication was seen for the SNPs rs7090445 (p = 0.009), rs7089424 (p = 0.005), rs7073837 (p = 0.03), and rs10740055 (p = 0.04). Somatic ARID5B deletions were seen in 16/1335 cases (1.2%), being more common in HeH than in other genetic subtypes (2.2% vs. 0.4%; p = 0.002). The expression of ARID5B in HeH cases with genomic deletions was reduced, consistent with a functional role in leukemogenesis. Whole-genome sequencing and RNA-sequencing in HeH revealed additional somatic events involving ARID5B, resulting in a total frequency of 3.6% of HeH cases displaying a somatic ARID5B aberration. Overall, our results show that both constitutional and somatic events in ARID5B are involved in the leukemogenesis of pediatric BCP ALL, particularly in the HeH subtype.
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Proteínas de Unión al ADN , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Factores de Transcripción , Niño , Preescolar , Femenino , Humanos , Masculino , Proteínas de Unión al ADN/genética , Polimorfismo de Nucleótido Simple , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Factores de Transcripción/genéticaRESUMEN
Allopurinol can be used in maintenance therapy (MT) for pediatric acute lymphoblastic leukemia (ALL) to mitigate hepatic toxicity in patients with skewed 6- mercaptopurine metabolism. Allopurinol increases the erythrocyte levels of thioguanine nucleotides (e-TGN), which is the proposed main mediator of the antileukemic effect and decreases methyl mercaptopurine (e-MeMP) levels, associated with hepatotoxicity. We investigated the effects of allopurinol in thiopurine methyltransferase (TPMT) wild-type patients without previous clinical signs of skewed 6MP metabolism. Fifty-one patients from Sweden and Finland were enrolled in this prospective beforeafter trial during ALL MT. Mean e-TGN increased from 280 nmol/mmol Hb after 12 weeks of standard MT to 440 after 12 weeks of MT with addition of allopurinol 50 mg/m2 (p.
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BACKGROUND: Childhood cancers affect about 350 children every year in Sweden and are life-threatening diseases. During the treatment period, situations arise that can become morally challenging for the child. When knowing children's values and morally challenging situations in childhood cancer care, targeted ethics support could be developed and used in care. AIM: To explore children's values and moral dilemmas ââwhen undergoing cancer treatment. METHODS: This is a qualitative study based on empirical data. The data collection was conducted through three focus group interviews and six individual interviews with children between 10 and 18 years (n = 16). A content analysis methodology was used to generate themes. Children who were/have been treated for cancer at three childhood cancer centres in Sweden were invited to participate. The study was approved by the Swedish Ethical Review Authority. The children's participation was based on voluntariness and consent/assent. FINDINGS: During the analysis, five themes of values emerged: Personal relationships, Bodily ease and identity, Feeling in control and being involved, Positive distractions and Right care that is needed. Their moral dilemmas were thematized into: Should I consider others or not? Should I rest or not? and Should I refuse treatment or not? CONCLUSION: Children undergoing cancer treatment want to have personal relationships with healthcare professionals. Their moral dilemmas were about questioning their own physical and psychological well-being against their expectations, the values of others and the treatment required. Further research is needed to understand how to deal with moral dilemmas in children undergoing cancer treatment.
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Principios Morales , Neoplasias , Investigación Cualitativa , Humanos , Neoplasias/terapia , Neoplasias/psicología , Niño , Femenino , Suecia , Masculino , Adolescente , Grupos Focales , Valores SocialesRESUMEN
High hyperdiploid acute lymphoblastic leukemia (ALL) is one of the most common malignancies in children. The main driver event of this disease is a nonrandom aneuploidy consisting of gains of whole chromosomes but without overt evidence of chromosomal instability (CIN). Here, we investigated the frequency and severity of defective sister chromatid cohesion-a phenomenon related to CIN-in primary pediatric ALL. We found that a large proportion (86%) of hyperdiploid cases displayed aberrant cohesion, frequently severe, to compare with 49% of ETV6/RUNX1-positive ALL, which mostly displayed mild defects. In hyperdiploid ALL, cohesion defects were associated with increased chromosomal copy number heterogeneity, which could indicate increased CIN. Furthermore, cohesion defects correlated with RAD21 and NCAPG mRNA expression, suggesting a link to reduced cohesin and condensin levels in hyperdiploid ALL. Knockdown of RAD21 in an ALL cell line led to sister chromatid cohesion defects, aberrant mitoses, and increased heterogeneity in chromosomal copy numbers, similar to what was seen in primary hyperdiploid ALL. In summary, our study shows that aberrant sister chromatid cohesion is frequent but heterogeneous in pediatric high hyperdiploid ALL, ranging from mild to very severe defects, and possibly due to low cohesin or condensin levels. Cases with high levels of aberrant chromosome cohesion displayed increased chromosomal copy number heterogeneity, possibly indicative of increased CIN. These abnormalities may play a role in the clonal evolution of hyperdiploid pediatric ALL.
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Cromátides/genética , Inestabilidad Cromosómica , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Niño , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Humanos , Ploidias , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Proteínas Proto-Oncogénicas c-ets/genética , Proteínas Represoras/genética , Proteína ETS de Variante de Translocación 6RESUMEN
BACKGROUND: In childhood cancer care, healthcare professionals must deal with several difficult moral situations in clinical practice. Previous studies show that morally difficult challenges are related to decisions on treatment limitations, infringing on the child's integrity and growing autonomy, and interprofessional conflicts. Research also shows that healthcare professionals have expressed a need for clinical ethics support to help them deal with morally difficult situations. Moral case deliberations (MCDs) are one example of ethics support. The aim of this study was to describe the MCD-related outcomes that healthcare professionals in childhood cancer care considered important, before MCDs were implemented, in order to facilitate the implementation of MCDs in childhood cancer care in Sweden. METHODS: This study is based on qualitative data. Healthcare professionals, mostly representing registered nurses, nursing assistants and physicians, working at childhood cancer care centres in Sweden, were invited to respond to the translated and content validated European MCD Outcomes Instrument, before participating in regular MCDs. Answers to the main open-ended question, included in the questionnaire, was analysed according to systematic text condensation. RESULTS: Data was collected from 161 responses from the healthcare professionals. The responses included healthcare professionals' perceptions of which MCD-related outcomes they found important for handling moral challenges. Three different themes of important outcomes from the analysis of the data are presented as follows: Interprofessional well-being in team interactions on a team level; Professional comfort when dealing with moral challenges on a personal level; and Improved quality of care for the child and the family on a care level. CONCLUSIONS: Healthcare professionals in childhood cancer care considered it important that ethics support could enhance the well-being of interprofessional teams, support healthcare professionals on an individual level and improve quality of care. The results of this study can be used in current and future training for MCD-facilitators. When knowing the context specific important MCD-outcomes, the sessions could be adapted. Managers in childhood cancer care would benefit from knowing about the specific important outcomes for their target group because they could then create relevant working conditions for clinical ethics support.
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Neoplasias , Niño , Atención a la Salud , Humanos , Principios Morales , Neoplasias/terapia , Percepción , Investigación Cualitativa , SueciaRESUMEN
In recent years, a subgroup of B-cell precursor acute lymphoblastic leukemia (BCP ALL) without an established abnormality ("B-other") has been shown to be characterized by rearrangements of ABL1, ABL2, CSF1R, or PDGFRB (a.k.a. ABL-class genes). Using FISH with probes for these genes, we screened 55 pediatric and 50 adult B-other cases. Three (6%) of the adult but none of the childhood B-other cases were positive for ABL-class aberrations. RT-PCR and sequencing confirmed a rare SFPQ-ABL1 fusion in one adult B-other case with t(1;9)(p34;q34). Only six SFPQ-ABL1-positive BCP ALLs have been reported, present case included. A review of these shows that all harbored fusions between exon 9 of SFPQ and exon 4 of ABL1, that the fusion is typically found in adolescents/younger adults without hyperleukocytosis, and that IKZF1 deletions are recurrent. The few patients not treated with tyrosine kinase inhibitors (TKIs) and/or allogeneic stem cell transplantation relapsed, strengthening the notion that TKI should be added to the therapy of SFPQ-ABL1-positive BCP ALL.
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Proteínas de Fusión Oncogénica/genética , Factor de Empalme Asociado a PTB/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Proteínas Proto-Oncogénicas c-abl/genética , Adolescente , Antineoplásicos/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Factor de Transcripción Ikaros/genética , Lactante , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Inhibidores de Proteínas Quinasas/uso terapéuticoRESUMEN
Single nucleotide polymorphism array (SNP-A) analyses are increasingly being introduced in routine genetic diagnostics of acute lymphoblastic leukemia (ALL). Despite this, only few studies that have compared the diagnostic value of SNP-A with conventional chromosome banding have been published. We here report such a comparison of 296 ALL cases, the largest series to date. Only genomic imbalances >5 Mb and microdeletions targeting the BTG1, CDKN2A/B, EBF1, ERG, ETV6, IKZF1, PAX5, and RB1 genes and the pseudoautosomal region 1 (PAR1) were ascertained, in agreement with recent guidelines. Of 36 T-cell ALL cases, the karyotypes of 24 cases (67%) were revised by SNP-A analyses that either revealed additional imbalances >5 Mb or better characterized the changes found by G-banding. Of 260 B-cell precursor (BCP) ALL cases, SNP-A analyses identified additional copy number alterations, including the above-mentioned microdeletions, or better characterized the imbalances found by G-banding in 236 (91%) cases. Furthermore, the cytogenetic subtype classification of 41/260 (16%) BCP ALL cases was revised based on the SNP-A findings. Of the subtype revisions, 12/41 (29%) had clinical implications as regards risk stratifying cytogenetic groups or genotype-specific minimal residual disease stratification. We conclude that SNP-A analyses dramatically improve the cytogenetic characterization of both T-cell and BCP ALL and also provide important information pertinent to risk stratification of BCP ALL.
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Polimorfismo de Nucleótido Simple/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiología , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Adolescente , Niño , Preescolar , Estudios de Cohortes , Análisis Citogenético , Humanos , Lactante , Recién Nacido , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnósticoRESUMEN
The prognostic value of minimal residual disease (MRD) in Philadelphia-chromosome-positive (Ph+) childhood acute lymphoblastic leukemia (ALL) treated with tyrosine kinase inhibitors is not fully established. We detected MRD by real-time quantitative polymerase chain reaction (RQ-PCR) of rearranged immunoglobulin/T-cell receptor genes (IG/TR) and/or BCR/ABL1 fusion transcript to investigate its predictive value in patients receiving Berlin-Frankfurt-Münster (BFM) high-risk (HR) therapy and post-induction intermittent imatinib (the European intergroup study of post-induction treatment of Philadelphia-chromosome-positive acute lymphoblastic leukemia (EsPhALL) study). MRD was monitored after induction (time point (TP)1), consolidation Phase IB (TP2), HR Blocks, reinductions, and at the end of therapy. MRD negativity progressively increased over time, both by IG/TR and BCR/ABL1. Of 90 patients with IG/TR MRD at TP1, nine were negative and none relapsed, while 11 with MRD<5×10-4 and 70 with MRD≥5×10-4 had a comparable 5-year cumulative incidence of relapse of 36.4 (15.4) and 35.2 (5.9), respectively. Patients who achieved MRD negativity at TP2 had a low relapse risk (5-yr cumulative incidence of relapse (CIR)=14.3[9.8]), whereas those who attained MRD negativity at a later date showed higher CIR, comparable to patients with positive MRD at any level. BCR/ABL1 MRD negative patients at TP1 had a relapse risk similar to those who were IG/TR MRD negative (1/8 relapses). The overall concordance between the two methods is 69%, with significantly higher positivity by BCR/ABL1. In conclusion, MRD monitoring by both methods may be functional not only for measuring response but also for guiding biological studies aimed at investigating causes for discrepancies, although from our data IG/TR MRD monitoring appears to be more reliable. Early MRD negativity is highly predictive of favorable outcome. The earlier MRD negativity is achieved, the better the prognosis.
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Proteínas de Fusión bcr-abl/genética , Inmunoglobulinas/genética , Neoplasia Residual/diagnóstico , Neoplasia Residual/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Receptores de Antígenos de Linfocitos T/genética , Biomarcadores de Tumor , Terapia Combinada , Femenino , Humanos , Mesilato de Imatinib/uso terapéutico , Masculino , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Pronóstico , Recurrencia , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
Osteonecrosis (ON) is usually considered treatment related in patients with acute lymphoblastic leukemia (ALL). We report two patients with presentation of ON at the time of ALL diagnosis. Both were females and diagnosed with ALL at age 8 and 14 years. In the latter, some symptoms and radiologically verified ON in both knees were still present after the end of ALL therapy. No pediatric patients have previously been reported with ON presenting before initiation of ALL therapy.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Osteonecrosis/patología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Adolescente , Niño , Femenino , Humanos , Osteonecrosis/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , PronósticoAsunto(s)
Leucemia Mieloide Aguda/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Cariotipo Anormal , Anciano , Anciano de 80 o más Años , Proteínas Reguladoras de la Apoptosis/genética , Niño , Deleción Cromosómica , Cromosomas Humanos Par 7/genética , Metilación de ADN , Proteínas de Unión al ADN/genética , Femenino , Impresión Genómica , Humanos , Masculino , Persona de Mediana Edad , Modelos Genéticos , Regiones Promotoras Genéticas , Proteínas/genética , Proteínas de Unión al ARN/genética , Adulto JovenRESUMEN
Cytogenetic analyses of a consecutive series of 67 paediatric (median age 8 years; range 0-17) de novo acute myeloid leukaemia (AML) patients revealed aberrations in 55 (82%) cases. The most common subgroups were KMT2A rearrangement (29%), normal karyotype (15%), RUNX1-RUNX1T1 (10%), deletions of 5q, 7q and/or 17p (9%), myeloid leukaemia associated with Down syndrome (7%), PML-RARA (7%) and CBFB-MYH11 (5%). Single nucleotide polymorphism array (SNP-A) analysis and exon sequencing of 100 genes, performed in 52 and 40 cases, respectively (39 overlapping), revealed ≥1 aberration in 89%; when adding cytogenetic data, this frequency increased to 98%. Uniparental isodisomies (UPIDs) were detected in 13% and copy number aberrations (CNAs) in 63% (median 2/case); three UPIDs and 22 CNAs were recurrent. Twenty-two genes were targeted by focal CNAs, including AEBP2 and PHF6 deletions and genes involved in AML-associated gene fusions. Deep sequencing identified mutations in 65% of cases (median 1/case). In total, 60 mutations were found in 30 genes, primarily those encoding signalling proteins (47%), transcription factors (25%), or epigenetic modifiers (13%). Twelve genes (BCOR, CEBPA, FLT3, GATA1, KIT, KRAS, NOTCH1, NPM1, NRAS, PTPN11, SMC3 and TP53) were recurrently mutated. We conclude that SNP-A and deep sequencing analyses complement the cytogenetic diagnosis of paediatric AML.
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Análisis Citogenético/métodos , Exones/genética , Leucemia Mieloide Aguda/genética , Polimorfismo de Nucleótido Simple , Adolescente , Niño , Preescolar , Humanos , Lactante , Recién Nacido , Leucemia Mieloide Aguda/diagnóstico , Mutación , Nucleofosmina , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: When offered participation in clinical trials, families of children with cancer face a delicate balance between cure and toxicity. Since parents and children may perceive this balance differently, this paper explores whether adolescent patients have different enrollment patterns compared to younger children in trials with different toxicity profiles. PROCEDURE: Age-dependent participation rates in three consecutive, randomized childhood leukemia trials conducted by the Nordic Society of Paediatric Haematology and Oncology were evaluated. The ALL2000 dexamethasone/vincristine (Dx/VCR) trial tested treatment intensifications to improve cure, and the back-to-back ALL2008 6-mercaptopurine (6MP) and ALL2008 PEG-asparaginase (ASP) trials tested treatment intensifications (6MP) and toxicity reduction without compromising survival (ASP). Patient randomization and toxicity data were prospectively registered by the treating physicians. RESULTS: Parents of young children favored treatment intensifications (Dx/VCR: 12% refusal; 6MP: 14%; ASP: 21%), whereas parents of adolescents favored treatment reductions (Dx/VCR: 52% refusal; 6MP: 30%; ASP: 8%). Adolescents were more likely to refuse intensification trials than young children (adjusted ORs 6.3; P < 0.01 [Dx/VCR] and 2.1; P = 0.04 [6MP]). Adolescents were less likely to refuse the ASP trial, with varying effect size depending on the length of the preceding consolidation treatment (adjusted OR for median consolidation length 0.15; P = 0.01). Younger children participated more frequently in only 6MP than in only ASP (14% vs. 5%), and adolescents vice versa (2% vs. 17%; P = 0.001). CONCLUSIONS: Parents' and adolescents' divergent inclinations toward intensified or reduced therapy emphasize the necessity of actively involving adolescents in the informed consent process, which should also address motives for trial participation.
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Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Prioridad del Paciente/psicología , Leucemia-Linfoma Linfoblástico de Células Precursoras , Negativa del Paciente al Tratamiento/psicología , Adolescente , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Asparaginasa/administración & dosificación , Asparaginasa/efectos adversos , Dexametasona/administración & dosificación , Dexametasona/efectos adversos , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Mercaptopurina/administración & dosificación , Mercaptopurina/efectos adversos , Persona de Mediana Edad , Padres/psicología , Polietilenglicoles/administración & dosificación , Polietilenglicoles/efectos adversos , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Leucemia-Linfoma Linfoblástico de Células Precursoras/psicología , Tasa de Supervivencia , Vincristina/administración & dosificación , Vincristina/efectos adversosRESUMEN
In contrast to IKZF1 deletions (ΔIKZF1), IKZF1 sequence mutations (mutIKZF1) have been reported to be rare in B-cell precursor acute lymphoblastic leukemia and their clinical implications are unknown. We performed targeted deep sequencing of all exons of IKZF1 in 140 pediatric cases, eight (5.7%) of which harbored a mutIKZF1. The probabilities of relapse (pRel) and event-free survival (pEFS) did not differ between cases with or without mutIKZF1, whereas pEFS was decreased and pRel increased in ΔIKZF1-positive case. Coexisting microdeletions, mutations (FLT3, JAK2, SH2B3, and SPRED1), and rearrangements (ABL1, CRLF2, JAK2, and PDGFRB) in 35 ΔIKZF1 and/or mutIKZF1-positive cases were ascertained using fluorescence in situ hybridization, single nucleotide polymorphism array, Sanger, and targeted deep sequencing analyses. The overall frequencies of copy number alterations did not differ between cases with our without ΔIKZF1/mutIKZF1. Deletions of HIST1, SH2B3, and the pseudoautosomal region (PAR1), associated with deregulation of CRLF2, were more common in ΔIKZF1-positive cases, whereas PAR1 deletions and JAK2 mutations were overrepresented in the combined ΔIKZF1/mutIKZF1 group. There was no significant impact on pRel of the deletions in ΔIKZF1-positive cases or of JAK2 mutations in cases with ΔIKZF1/mutIKZF1. In contrast, the pRel was higher (P = 0.005) in ΔIKZF1/mutIKZF1-positive cases with PAR1 deletions.
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Factor de Transcripción Ikaros/genética , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Eliminación de Secuencia , Adolescente , Secuencia de Bases , Niño , Humanos , Polimorfismo de Nucleótido Simple , PronósticoAsunto(s)
Mesilato de Imatinib/administración & dosificación , Cromosoma Filadelfia , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Adolescente , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Lactante , Recuento de Leucocitos , Masculino , Tasa de SupervivenciaRESUMEN
BACKGROUND: Trials of imatinib have provided evidence of activity in adults with Philadelphia-chromosome-positive acute lymphoblastic leukaemia (ALL), but the drug's role when given with multidrug chemotherapy to children is unknown. This study assesses the safety and efficacy of oral imatinib in association with a Berlin-Frankfurt-Munster intensive chemotherapy regimen and allogeneic stem-cell transplantation for paediatric patients with Philadelphia-chromosome-positive ALL. METHODS: Patients aged 1-18 years recruited to national trials of front-line treatment for ALL were eligible if they had t(9;22)(q34;q11). Patients with abnormal renal or hepatic function, or an active systemic infection, were ineligible. Patients were enrolled by ten study groups between 2004 and 2009, and were classified as good risk or poor risk according to early response to induction treatment. Good-risk patients were randomly assigned by a web-based system with permuted blocks (size four) to receive post-induction imatinib with chemotherapy or chemotherapy only in a 1:1 ratio, while all poor-risk patients received post-induction imatinib with chemotherapy. Patients were stratified by study group. The chemotherapy regimen was modelled on a Berlin-Frankfurt-Munster high-risk backbone; all received four post-induction blocks of chemotherapy after which they became eligible for stem-cell transplantation. The primary endpoints were disease-free survival at 4 years in the good-risk group and event-free survival at 4 years in the poor-risk group, analysed by intention to treat and a secondary analysis of patients as treated. The trial is registered with EudraCT (2004-001647-30) and ClinicalTrials.gov, number NCT00287105. FINDINGS: Between Jan 1, 2004, and Dec 31, 2009, we screened 229 patients and enrolled 178: 108 were good risk and 70 poor risk. 46 good-risk patients were assigned to receive imatinib and 44 to receive no imatinib. Median follow-up was 3·1 years (IQR 2·0-4·6). 4-year disease-free survival was 72·9% (95% CI 56·1-84·1) in the good-risk, imatinib group versus 61·7% (45·0-74·7) in the good-risk, no imatinib group (p=0·24). The hazard ratio (HR) for failure, adjusted for minimal residual disease, was 0·63 (0·28-1·41; p=0·26). The as-treated analysis showed 4-year disease-free survival was 75·2% (61·0-84·9) for good-risk patients receiving imatinib and 55·9% (36·1-71·7) for those who did not receive imatinib (p=0·06). 4-year event-free survival for poor-risk patients was 53·5% (40·4-65·0). Serious adverse events were much the same in the good-risk groups, with infections caused by myelosuppression the most common. 16 patients in the good-risk imatinib group versus ten in the good-risk, no imatinib group (p=0·64), and 24 in the poor-risk group, had a serious adverse event. INTERPRETATION: Our results suggests that imatinib in conjunction with intensive chemotherapy is well tolerated and might be beneficial for treatment of children with Philadelphia-chromosome-positive ALL. FUNDING: Projet Hospitalier de Recherche Clinique-Cancer (France), Fondazione Tettamanti-De Marchi and Associazione Italiana per la Ricerca sul Cancro (Italy), Novartis Germany, Cancer Research UK, Leukaemia Lymphoma Research, and Central Manchester University Hospitals Foundation Trust.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Cromosoma Filadelfia , Piperazinas/administración & dosificación , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Pirimidinas/administración & dosificación , Adolescente , Benzamidas , Niño , Preescolar , Supervivencia sin Enfermedad , Femenino , Humanos , Mesilato de Imatinib , Incidencia , Lactante , Masculino , Recurrencia Local de Neoplasia/epidemiología , Neoplasia Residual , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Leucemia-Linfoma Linfoblástico de Células Precursoras/cirugía , Medición de Riesgo , Trasplante de Células Madre , Tasa de SupervivenciaRESUMEN
High hyperdiploid acute lymphoblastic leukemia (HeH ALL), one of the most common childhood malignancies, is driven by nonrandom aneuploidy (abnormal chromosome numbers) mainly comprising chromosomal gains. In this study, we investigate how aneuploidy in HeH ALL arises. Single cell whole genome sequencing of 2847 cells from nine primary cases and one normal bone marrow reveals that HeH ALL generally display low chromosomal heterogeneity, indicating that they are not characterized by chromosomal instability and showing that aneuploidy-driven malignancies are not necessarily chromosomally heterogeneous. Furthermore, most chromosomal gains are present in all leukemic cells, suggesting that they arose early during leukemogenesis. Copy number data from 577 primary cases reveals selective pressures that were used for in silico modeling of aneuploidy development. This shows that the aneuploidy in HeH ALL likely arises by an initial tripolar mitosis in a diploid cell followed by clonal evolution, in line with a punctuated evolution model.
Asunto(s)
Aneuploidia , Leucemia-Linfoma Linfoblástico de Células Precursoras , Humanos , Aberraciones Cromosómicas , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Diploidia , Inestabilidad CromosómicaRESUMEN
The cellular targets of primary mutations and malignant transformation remain elusive in most cancers. Here, we show that clinically and genetically different subtypes of acute lymphoblastic leukemia (ALL) originate and transform at distinct stages of hematopoietic development. Primary ETV6-RUNX1 (also known as TEL-AML1) fusions and subsequent leukemic transformations were targeted to committed B-cell progenitors. Major breakpoint BCR-ABL1 fusions (encoding P210 BCR-ABL1) originated in hematopoietic stem cells (HSCs), whereas minor BCR-ABL1 fusions (encoding P190 BCR-ABL1) had a B-cell progenitor origin, suggesting that P190 and P210 BCR-ABL1 ALLs represent largely distinct tumor biological and clinical entities. The transformed leukemia-initiating stem cells in both P190 and P210 BCR-ABL1 ALLs had, as in ETV6-RUNX1 ALLs, a committed B progenitor phenotype. In all patients, normal and leukemic repopulating stem cells could successfully be separated prospectively, and notably, the size of the normal HSC compartment in ETV6-RUNX1 and P190 BCR-ABL1 ALLs was found to be unaffected by the expansive leukemic stem cell population.
Asunto(s)
Proteínas de Fusión bcr-abl/fisiología , Células Madre Hematopoyéticas/fisiología , Leucemia-Linfoma Linfoblástico de Células Precursoras/clasificación , ADP-Ribosil Ciclasa , ADP-Ribosil Ciclasa 1 , Adulto , Antígenos CD , Antígenos CD19 , Antígenos CD34 , Niño , Cromosomas Humanos Par 12 , Cromosomas Humanos Par 21 , Subunidad alfa 2 del Factor de Unión al Sitio Principal , Proteínas de Unión al ADN/fisiología , Citometría de Flujo , Proteínas de Fusión bcr-abl/genética , Humanos , Glicoproteínas de Membrana , Mutación , Proteínas Nucleares/fisiología , Proteínas de Fusión Oncogénica/fisiología , Fenotipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/inmunología , Leucemia-Linfoma Linfoblástico de Células Precursoras/patología , Proteínas Proto-Oncogénicas c-ets , Proteínas Represoras/fisiología , Translocación Genética , Proteína ETS de Variante de Translocación 6RESUMEN
Infant acute lymphoblastic leukemia (ALL) with KMT2A-gene rearrangements (KMT2A-r) have few mutations and a poor prognosis. To uncover mutations that are below the detection of standard next-generation sequencing (NGS), a combination of targeted duplex sequencing and NGS was applied on 20 infants and 7 children with KMT2A-r ALL, 5 longitudinal and 6 paired relapse samples. Of identified nonsynonymous mutations, 87 had been previously implicated in cancer and targeted genes recurrently altered in KMT2A-r leukemia and included mutations in KRAS, NRAS, FLT3, TP53, PIK3CA, PAX5, PIK3R1, and PTPN11, with infants having fewer such mutations. Of identified cancer-associated mutations, 62% were below the resolution of standard NGS. Only 33 of 87 mutations exceeded 2% of cellular prevalence and most-targeted PI3K/RAS genes (31/33) and typically KRAS/NRAS. Five patients only had low-frequency PI3K/RAS mutations without a higher-frequency signaling mutation. Further, drug-resistant clones with FLT3 D835H or NRAS G13D/G12S mutations that comprised only 0.06% to 0.34% of diagnostic cells, expanded at relapse. Finally, in longitudinal samples, the relapse clone persisted as a minor subclone from diagnosis and through treatment before expanding during the last month of disease. Together, we demonstrate that infant and childhood KMT2A-r ALL harbor low-frequency cancer-associated mutations, implying a vast subclonal genetic landscape.