Relapse is the main reason for treatment failure in childhood acute lymphoblastic leukemia. Despite improvements in the up-front therapy, survival after relapse is still relatively poor, especially ...for high-risk relapses. The aims of this study were to assess outcomes following acute lymphoblastic leukemia relapse after common initial Nordic Society of Paediatric Haematology and Oncology protocol treatment; to validate currently used risk stratifications, and identify additional prognostic factors for overall survival. Altogether, 516 of 2735 patients (18.9%) relapsed between 1992 and 2011 and were included in the study. There were no statistically significant differences in outcome between the up-front protocols or between the relapse protocols used, but an improvement over time was observed. The 5-year overall survival for patients relapsing in the period 2002-2011 was 57.5±3.4%, but 44.7±3.2% (P<0.001) if relapse occurred in the period 1992-2001. Factors independently predicting mortality after relapse included short duration of first remission, bone marrow involvement, age ten years or over, unfavorable cytogenetics, and Down syndrome. T-cell immunophenotype was not an independent prognostic factor unless in combination with hyperleukocytosis at diagnosis. The outcome for early combined pre-B relapses was unexpectedly poor (5-year overall survival 38.0±10.6%), which supports the notion that these patients need further risk adjustment. Although survival outcomes have improved over time, the development of novel approaches is urgently needed to increase survival in relapsed childhood acute lymphoblastic leukemia.
To evaluate the early treatment response in children with acute myeloid leukemia (AML) using a response-guided induction strategy that includes idarubicin in the first course.
All Nordic children ...with AML younger than 15 years (n = 151) were treated on the Nordic Society for Pediatric Hematology and Oncology (NOPHO) AML 2004 protocol. After the first course of idarubicin, cytarabine, etoposide, and 6-thioguanin, patients with good response were allowed hematologic recovery before the second course, whereas patients with a poor (≥ 15% blasts) or intermediate (5% to 14.9% blasts) were recommended to proceed immediately with therapy. Patients not in remission after the second course received fludarabine, cytarabine, and granulocyte colony-stimulating factor. Poor responders received allogeneic stem-cell transplantation (SCT) as consolidation.
Seventy-four percent of patients had good response, 17% had intermediate response, and 7% had poor response after the first course. The overall remission frequency was 97.4%, with 92% in remission after the second course. The rate of induction death was 1.3%. Patients with an intermediate response had a lower event-free survival of 35% compared with good (61%) and poor responders (82%).
The NOPHO-AML 2004 induction strategy gives an excellent remission rate with low toxic mortality in an unselected population. Outcome is worse in patients with intermediate response but may be improved by intensifying consolidation in this group using SCT.
High hyperdiploid acute lymphoblastic leukemia (ALL) is one of the most common malignancies in children. It is characterized by gain of chromosomes, typically +X, +4, +6, +10, +14, +17, +18, and +21, ...+21; little is known about additional genetic aberrations. Approximately 20% of the patients relapse; therefore it is clinically important to identify risk-stratifying markers. We used SNP array analysis to investigate a consecutive series of 74 cases of high hyperdiploid ALL. We show that the characteristic chromosomal gains are even more frequent than previously believed, indicating that karyotyping mistakes are common, and that almost 80% of the cases display additional abnormalities detectable by SNP array analysis. Subclonality analysis strongly implied that the numerical aberrations were primary and arose before structural events, suggesting that step-wise evolution of the leukemic clone is common. An association between duplication of 1q and +5 was seen (P = 0.003). Other frequent abnormalities included whole-chromosome uniparental isodisomies (wUPIDs) 9 and 11, gain of 17q not associated with isochromosome formation, extra gain of part of 21q, deletions of ETS variant 6 (ETV6), cyclin-dependent kinase inhibitor 2A (CKDN2A) and paired box 5 (PAX5), and PAN3 poly(A) specific ribonuclease subunit homolog (PAN3) microdeletions. Comparison of whole-chromosome and partial UPID9 suggested different pathogenetic outcomes, with the former not involving CDKN2A. Finally, two cases had partial deletions of AT rich interactive domain 5B (ARID5B), indicating that acquired as well as constitutional variants in this locus may be associated with pediatric ALL. Here we provide a comprehensive characterization of the genetic landscape of high hyperdiploid childhood ALL, including the heterogeneous pattern of secondary genetic events.
Translocations involving chromosome 11q23 frequently occur in pediatric acute myeloid leukemia (AML) and are associated with poor prognosis. In most cases, the MLL gene is involved, and more than 50 ...translocation partners have been described. Clinical outcome data of the 11q23-rearranged subgroups are scarce because most 11q23 series are too small for meaningful analysis of subgroups, although some studies suggest that patients with t(9;11)(p22;q23) have a more favorable prognosis. We retrospectively collected outcome data of 756 children with 11q23- or MLL-rearranged AML from 11 collaborative groups to identify differences in outcome based on translocation partners. All karyotypes were centrally reviewed before assigning patients to subgroups. The event-free survival of 11q23/MLL-rearranged pediatric AML at 5 years from diagnosis was 44% (± 5%), with large differences across subgroups (11% ± 5% to 92% ± 5%). Multivariate analysis identified the following subgroups as independent prognostic predictors: t(1;11)(q21;q23) (hazard ratio HR = 0.1, P = .004); t(6;11)(q27;q23) (HR = 2.2, P < .001); t(10;11)(p12;q23) (HR = 1.5, P = .005); and t(10;11)(p11.2;q23) (HR = 2.5, P = .005). We could not confirm the favorable prognosis of the t(9;11)(p22;q23) subgroup. We identified large differences in outcome within 11q23/MLL-rearranged pediatric AML and novel subgroups based on translocation partners that independently predict clinical outcome. Screening for these translocation partners is needed for accurate treatment stratification at diagnosis.
Comprehensive clinical studies of patients with acute megakaryoblastic leukemia (AMKL) are lacking. We performed an international retrospective study on 490 patients (age ≤18 years) with non–Down ...syndrome de novo AMKL diagnosed from 1989 to 2009. Patients with AMKL (median age 1.53 years) comprised 7.8% of pediatric AML. Five-year event-free (EFS) and overall survival (OS) were 43.7% ± 2.7% and 49.0% ± 2.7%, respectively. Patients diagnosed in 2000 to 2009 were treated with higher cytarabine doses and had better EFS (P = .037) and OS (P = .003) than those diagnosed in 1989 to 1999. Transplantation in first remission did not improve survival. Cytogenetic data were available for 372 (75.9%) patients: hypodiploid (n = 18, 4.8%), normal karyotype (n = 49, 13.2%), pseudodiploid (n = 119, 32.0%), 47 to 50 chromosomes (n = 142, 38.2%), and >50 chromosomes (n = 44, 11.8%). Chromosome gain occurred in 195 of 372 (52.4%) patients: +21 (n = 106, 28.5%), +19 (n = 93, 25.0%), +8 (n = 77, 20.7%). Losses occurred in 65 patients (17.5%): –7 (n = 13, 3.5%). Common structural chromosomal aberrations were t(1;22)(p13;q13) (n = 51, 13.7%) and 11q23 rearrangements (n = 38, 10.2%); t(9;11)(p22;q23) occurred in 21 patients. On the basis of frequency and prognosis, AMKL can be classified to 3 risk groups: good risk—7p abnormalities; poor risk—normal karyotypes, –7, 9p abnormalities including t(9;11)(p22;q23)/MLL-MLLT3, –13/13q-, and –15; and intermediate risk—others including t(1;22)(p13;q13)/OTT-MAL (RBM15-MKL1) and 11q23/MLL except t(9;11). Risk-based innovative therapy is needed to improve patient outcomes.
•AMKL patients in 2000 to 2009 had better survival than those in 1989 to 1999, but outcomes for patients in 2000 to 2004 and 2005 to 2009 were comparable.•Heterogeneous cytogenetic groups can be classified into good, intermediate, and poor risk on the basis of prognosis.
Treatment of pediatric T-cell acute lymphoblastic leukemia (T-ALL) has improved, but there is a considerable fraction of patients experiencing a poor outcome. There is a need for better prognostic ...markers and aberrant DNA methylation is a candidate in other malignancies, but its potential prognostic significance in T-ALL is hitherto undecided.
Genome wide promoter DNA methylation analysis was performed in pediatric T-ALL samples (n = 43) using arrays covering >27000 CpG sites. Clinical outcome was evaluated in relation to methylation status and compared with a contemporary T-ALL group not tested for methylation (n = 32).
Based on CpG island methylator phenotype (CIMP), T-ALL samples were subgrouped as CIMP+ (high methylation) and CIMP- (low methylation). CIMP- T-ALL patients had significantly worse overall and event free survival (p = 0.02 and p = 0.001, respectively) compared to CIMP+ cases. CIMP status was an independent factor for survival in multivariate analysis including age, gender and white blood cell count. Analysis of differently methylated genes in the CIMP subgroups showed an overrepresentation of transcription factors, ligands and polycomb target genes.
We identified global promoter methylation profiling as being of relevance for subgrouping and prognostication of pediatric T-ALL.
Among 1614 children with acute lymphoblastic leukemia (ALL) treated with the Nordic Society for Paediatric Haematology and Oncology (NOPHO) ALL-92 protocol, 20 patients developed a second malignant ...neoplasm (SMN) with a cumulative risk of 1.6% at 12 years from the diagnosis of ALL. Nine of the 16 acute myeloid leukemias or myelodysplastic syndromes had monosomy 7 (n = 7) or 7q deletions (n = 2). In Cox multivariate analysis, longer duration of oral 6-mercaptopurine (6MP)/methotrexate (MTX) maintenance therapy (P = .02; longest for standard-risk patients) and presence of high hyperdiploidy (P = .07) were related to increased risk of SMN. Thiopurine methyltransferase (TPMT) methylates 6MP and its metabolites, and thus reduces cellular levels of cytotoxic 6-thioguanine nucleotides. Of 524 patients who had erythrocyte TPMT activity measured, the median TPMT activity in 9 patients developing an SMN was significantly lower than in the 515 that did not develop an SMN (median, 12.1 vs 18.1 IU/mL; P = .02). Among 427 TPMT wild-type patients for whom the 6MP dose was registered, those who developed SMN received higher average 6MP doses than the remaining patients (69.7 vs 60.4 mg/m2; P = .03). This study indicates that the duration and intensity of 6MP/MTX maintenance therapy of childhood ALL may influence the risk of SMNs in childhood ALL.
Mutation status of FLT3, NPM1, CEBPA, and WT1 genes and gene expression levels of ERG, MN1, BAALC, FLT3, and WT1 have been identified as possible prognostic markers in acute myeloid leukemia (AML). ...We have performed a thorough prognostic evaluation of these genetic markers in patients with pediatric AML enrolled in the Nordic Society of Pediatric Hematology and Oncology (NOPHO) 1993 or NOPHO 2004 protocols. Mutation status and expression levels were analyzed in 185 and 149 patients, respectively. Presence of FLT3-internal tandem duplication (ITD) was associated with significantly inferior event-free survival (EFS), whereas presence of an NPM1 mutation in the absence of FLT3-ITD correlated with significantly improved EFS. Furthermore, high levels of ERG and BAALC transcripts were associated with inferior EFS. No significant correlation with survival was seen for mutations in CEBPA and WT1 or with gene expression levels of MN1, FLT3, and WT1. In multivariate analysis, the presence of FLT3-ITD and high BAALC expression were identified as independent prognostic markers of inferior EFS. We conclude that analysis of the mutational status of FLT3 and NPM1 at diagnosis is important for prognostic stratification of patients with pediatric AML and that determination of the BAALC gene expression level can add valuable information.
Structural chromosomal rearrangements that lead to expressed fusion genes are a hallmark of acute lymphoblastic leukemia (ALL). In this study, we performed transcriptome sequencing of 134 primary ALL ...patient samples to comprehensively detect fusion transcripts.
We combined fusion gene detection with genome-wide DNA methylation analysis, gene expression profiling, and targeted sequencing to determine molecular signatures of emerging ALL subtypes.
We identified 64 unique fusion events distributed among 80 individual patients, of which over 50% have not previously been reported in ALL. Although the majority of the fusion genes were found only in a single patient, we identified several recurrent fusion gene families defined by promiscuous fusion gene partners, such as ETV6, RUNX1, PAX5, and ZNF384, or recurrent fusion genes, such as DUX4-IGH. Our data show that patients harboring these fusion genes displayed characteristic genome-wide DNA methylation and gene expression signatures in addition to distinct patterns in single nucleotide variants and recurrent copy number alterations.
Our study delineates the fusion gene landscape in pediatric ALL, including both known and novel fusion genes, and highlights fusion gene families with shared molecular etiologies, which may provide additional information for prognosis and therapeutic options in the future.
Between 1992 and 2008, 713 high hyperdiploid acute lymphoblastic leukemias in children aged 1-15 years were diagnosed and treated according to the Nordic Society for Pediatric Hematology and Oncology ...acute lymphoblastic leukemia 1992/2000 protocols. Twenty (2.8%) harbored t(1;19), t(9;22), der(11q23), or t(12;21). The median age of patients with "classic" high hyperdiploidy was lower than that of patients with translocation-positive high hyperdiploidy (P<0.001). Cases with triple trisomies (+4, +10, +17), comprising 50%, had higher modal numbers than the triple trisomy-negative cases (P<0.0001). The probabilities of event-free survival and overall survival were lower for those with white blood cell counts ≥ 50 × 10(9)/L (P=0.017/P=0.009), ≥ 5% bone marrow blasts at day 29 (P=0.001/0.002), and for high-risk patients (P<0.001/P=0.003), whereas event-free, but not overall, survival, was higher for cases with gains of chromosomes 4 (P<0.0001), 6 (P<0.003), 17 (P=0.010), 18 (P=0.049), and 22 (P=0.040), triple trisomies (P=0.002), and modal numbers >53/55 (P=0.020/0.024). In multivariate analyses, modal number and triple trisomies were significantly associated with superior event-free survival in separate analyses with age and white blood cell counts. When including both modal numbers and triple trisomies, only low white blood cell counts were significantly associated with superior event-free survival (P=0.009). We conclude that high modal chromosome numbers and triple trisomies are highly correlated prognostic factors and that these two parameters identify the same subgroup of patients characterized by a particularly favorable outcome.
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