Predisposition to prolonged neutropenia after chemotherapy for paediatric acute myeloid leukaemia is associated with better prognosis in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study.

The variability in myelosuppression after chemotherapy for acute myeloid leukaemia (AML) can affect its prognosis; however, the underlying mechanism remains controversial. In the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-05 study, we showed that prolonged neutropenia was associated with high overall survival (P = 0·011) and low frequency of relapse (P = 0·042) in patients without granulocyte-colony stimulating factor (G-CSF) who completed the indicated treatment protocol. Our data indicate that predisposition to prolonged neutropenia after chemotherapy is correlated with a better outcome of AML treatment. Our results promote the usage of individualised drug dosing strategies to improve the therapeutic outcome in AML patients.

Droplet digital polymerase chain reaction assay for the detection of the minor clone of KIT D816V in paediatric acute myeloid leukaemia especially showing RUNX1-RUNX1T1 transcripts.

KIT D816V mutation within exon 17 has been particularly reported as one of the poor prognostic factors in pediatric acute myeloid leukemia (AML) with RUNX1-RUNX1T1. The exact frequency and the prognostic impact of KIT D816V minor clones at diagnosis were not examined. In this study, the minor clones were examined and the prognostic significance of KIT D816V mutation in pediatric patients was investigated. Consequently, 24 KIT D816V mutations (7.2%) in 335 pediatric patients were identified, and 12 of 24 were only detected via the digital droplet polymerase chain reaction method. All 12 patients were confined in core binding factor (CBF)-AML patients. The 5 year event-free survival of the patients with KIT D816V mutation was significantly inferior to those without KIT D816V mutation (44.1% [95% confidence interval (CI), 16.0%-69.4%] vs. 74.7% [95% CI, 63.0%-83.2%] P-value = 0.02, respectively). The 5 year overall survival was not different between the two groups (92.9% [95% CI, 59.0%-NA vs. 89.7% [95% CI, 69.6%-96.8%] P-value = 0.607, respectively). In this study, KIT D816V minor clones in patients with CBF-AML were confirmed and KIT D816V was considered as a risk factor for relapse in patients with RUNX1-RUNX1T1-positive AML.

Diffuse Large B-Cell Lymphoma of the Trachea in a Child With Symptoms of Bronchial Asthma.

Tracheal tumors are rare in children and manifest symptoms of airway obstruction. A 14-year-old boy with a 5-month history of dyspnea and wheezing was referred to our hospital. Although he had been initially diagnosed with bronchial asthma, computed tomography revealed tracheal tumors. Histologic examination showed only necrotic tissue. Thereafter, the systemic steroid treatment for bronchial asthma was tapered off. A second computed tomography scan revealed new lesions in the pancreas and lung. Biopsy of the pancreatic lesion revealed a diffuse large B-cell lymphoma. The patient was administered standard chemotherapy, following which he went into complete remission.

Patients aged less than 3 years with acute myeloid leukaemia characterize a molecularly and clinically distinct subgroup.

Although infants (age <1 year) with acute myeloid leukaemia (AML) have unique characteristics and are vulnerable to chemotherapy, children aged 1-2 years with AML may have characteristics similar to that of infants. Thus, we analysed 723 paediatric AML patients treated on the Japanese AML99 and AML-05 trials to identify characteristics of younger children. We identified patients aged <3 years (the younger group) as a distinct subgroup. KMT2A-rearrangement (KMT2A-R), CBFA2T3-GLIS2, CBFB-MYH11 and NUP98-KDM5A were frequently found in the younger group. Prognostic analyses revealed poor 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) in patients with CBFA2T3-GLIS2 (42%, 17% and 83%, respectively) and those with NUP98-KDM5A (33%, 17% and 83%, respectively). Additionally, we identified KMT2A-R and CBFB-MYH11 as age-specific prognostic markers. Regarding KMT2A-R, the younger group had significantly better OS, EFS and CIR than the older group (aged 3 to <18 years) (P = 0·023, 0·011 and <0·001, respectively). Conversely, concerning CBFB-MYH11, the younger group had significantly poor EFS and CIR than the older group (each P < 0·001), suggesting that certain molecular markers are linked to different prognoses according to age. Therefore, we characterized patients <3 years as a distinct subgroup of paediatric AML.

Attempts to optimize postinduction treatment in childhood acute myeloid leukemia without core-binding factors: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG).

We previously reported that risk-stratified therapy and intensive postremission chemotherapy (PRC) contributed to the improved survival of childhood acute myeloid leukemia (AML) in the AML99 study, which led us to consider a reduction in the number of PRC courses with more restrictive indications for stem cell transplantation (SCT) in the successor AML-05 study. We here report the outcome of AML patients without core-binding factor mutation (non-CBF AML) in the AML-05 study. Two-hundred eighty-nine children (age < 18 years old) with non-CBF AML were eligible. Patients with unfavorable cytogenetics and/or poor bone marrow response to the first induction course were candidates for SCT in the AML-05 study. After two courses of induction, a further three courses of PRC were given in AML-05, while four courses were given in the AML99 study. The 3-year event-free survival (EFS) rate in the AML-05 study (46.7%, 95% CI: 40.6-52.6%) was comparable to that of non-CBF AML in the AML99 study (51.5%, 95% CI: 42.7-59.6%) (P = .16). However, the 3-year overall survival (OS) rate in the AML-05 study (62.9%, 95% CI: 56.3-68.8%) was slightly lower than that in the AML99 study (71.6%, 95% CI: 63.2-78.5%) (P = .060), mainly due to decreased remission induction rate and increased nonrelapsed mortality. In conclusion, reductions in the number of PRC courses from four to three, together with repetitive cycles of high-dose cytarabine, were acceptable for non-CBF childhood AML.

Monitoring of fusion gene transcripts to predict relapse in pediatric acute myeloid leukemia.

BACKGROUND: In acute myeloid leukemia (AML), accurate detection of minimal residual disease (MRD) enables better risk-stratified therapy. There are few studies, however, on the monitoring of multiple fusion transcripts and evaluation of their accuracy as indicators of MRD at multiple time points. METHODS: We retrospectively examined RNA obtained from 82 pediatric AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 study. The expression of six important fusion transcripts (AML1(RUNX1)-ETO, CBFB-MYH11, MLL(KMT2A)-AF9, MLL-ELL, MLL-AF6, and FUS-ERG) was analyzed at five time points 30-40 days apart following diagnosis. RESULTS: In patients with AML1-ETO (n = 36 at time point 5), all six patients with >3,000 copies and four of 30 patients with ≤3,000 copies relapsed. AML1-ETO transcripts persisted during treatment even in patients without relapse, as well as CBFB-MYH11 transcripts. In contrast, in patients with MLL-AF9 (n = 9 at time point 5), two patients were positive for MLL-AF9 expression (>50 copies) and both relapsed. Only one of seven MLL-AF9-negative patients relapsed. In the AML1-ETO group, MRD-positive patients (>3,000 copies at time point 5) had significantly lower relapse-free survival (RFS; P < 0.0001) and overall survival (OS; P = 0.009) than MRD-negative patients. Similarly, in the MLL-AF9 group, MRD-positive patients (>50 copies at time point 5) had significantly lower RFS (P = 0.002) and OS (P = 0.002) than MRD-negative patients. CONCLUSIONS: Detection of MLL-AF9 transcripts on real-time quantitative polymerase chain reaction is a promising marker of relapse in pediatric AML. In contrast, the clinical utility of detecting AML1-ETO and CBFB-MYH11 expression is limited, although higher AML1-ETO expression can be a potential predictor of relapse when assessed according to an optimal threshold.

Multiplex fusion gene testing in pediatric acute myeloid leukemia.

BACKGROUND: Gene abnormalities, particularly chromosome rearrangements generating gene fusion, are associated with clinical characteristics and prognosis in pediatric acute myeloid leukemia (AML). Karyotyping is generally performed to enable risk stratification, but the results are not always consistent with those of reverse transcription-polymerase chain reaction (RT-PCR), and more accurate and rapid methods are required. METHODS: A total of 487 samples from de novo AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) AML-05 study (n = 448), and from acute promyelocytic leukemia (APL) patients enrolled in the JPLSG AML-P05 study (n = 39) were available for this investigation. Multiplex quantitative RT-PCR was performed to detect eight important fusion genes: AML1(RUNX1)-ETO(RUNX1T1), CBFB-MYH11, MLL(KMT2A)-AF9(MLLT3), MLL-ELL, MLL-AF6(MLLT4), FUS(TLS)-ERG, NUP98-HOXA9, and PML-RARA. RESULTS: Fusion genes were detected in 207 (46.2%) of the 448 AML-05 patient samples. After exclusion of two samples with PML-RARA, no chromosomal abnormalities were identified on karyotyping in 19 of 205 patients (9.3%) positive for fusion genes on RT-PCR. Fusion genes were confirmed on fluorescence in situ hybridization (FISH) in 11 of these 19 patients. In contrast, fusion genes were detected in 37 of 39 patients (94.9%) from the AML-P05 study, and 33 of these results were consistent with the karyotyping. There were discrepancies in four patients (10.8%), three with normal karyotypes and one in whom karyotyping was not possible. All four of these patients were PML-RARA positive on FISH. CONCLUSIONS: Multiplex quantitative RT-PCR-based fusion gene screening may be effective for diagnosis of pediatric AML.

Prognostic impact of specific molecular profiles in pediatric acute megakaryoblastic leukemia in non-Down syndrome.

Pediatric acute megakaryoblastic leukemia in non-Down syndrome (AMKL) is a unique subtype of acute myeloid leukemia (AML). Novel CBFA2T3-GLIS2 and NUP98-KDM5A fusions recurrently found in AMKL were recently reported as poor prognostic factors. However, their detailed clinical and molecular characteristics in patients treated with recent improved therapies remain uncertain. We analyzed molecular features of 44 AMKL patients treated on two recent Japanese AML protocols, the AML99 and AML-05 trials. We identified CBFA2T3-GLIS2, NUP98-KDM5A, RBM15-MKL1, and KMT2A rearrangements in 12 (27%), 4 (9%), 2 (5%), and 3 (7%) patients, respectively. Among 459 other AML patients, NUP98-KDM5A was identified in 3 patients, whereas CBFA2T3-GLIS2 and RBM15-MKL1 were only present in AMKL. GATA1 mutations were found in 5 patients (11%). Four-year overall survival (OS) and event-free survival (EFS) rates of CBFA2T3-GLIS2-positive patients in AMKL were 41.7% and 16.7%, respectively. Three-year cumulative incidence of relapse in CBFA2T3-GLIS2-positive patients was significantly higher than that of CBFA2T3-GLIS2-negative patients (75.0% vs. 35.7%, P = 0.024). In multivariate analyses, CBFA2T3-GLIS2 was an independent poor prognostic factor for OS (HR, 4.34; 95% CI, 1.31-14.38) and EFS (HR, 2.95; 95% CI, 1.20-7.23). Furthermore, seven (54%) of 13 infant AMKL patients were CBFA2T3-GLIS2-positive. Notably, out of 7 CBFA2T3-GLIS2-positive infants, six (86%) relapsed and five (71%) died. Moreover, all of CBFA2T3-GLIS2-positive patients who experienced induction failure (n = 3) were infants, indicating worse prognosis of CBFA2T3-GLIS2-positive infants. These findings indicated the significance of CBFA2T3-GLIS2 as a poor prognostic factor in AMKL patients, particularly in infants.

ASXL2 mutations are frequently found in pediatric AML patients with t(8;21)/ RUNX1-RUNX1T1 and associated with a better prognosis.

ASXL2 is an epigenetic regulator involved in polycomb repressive complex regulation or recruitment. Clinical features of pediatric acute myeloid leukemia (AML) patients with ASXL2 mutations remain unclear. Thus, we investigated frequencies of ASXL1 and ASXL2 mutations, clinical features of patients with these mutations, correlations of these mutations with other genetic alterations including BCOR/BCORL1 and cohesin complex component genes, and prognostic impact of these mutations in 369 pediatric patients with de novo AML (0-17 years). We identified 9 (2.4%) ASXL1 and 17 (4.6%) ASXL2 mutations in 25 patients. These mutations were more common in patients with t(8;21)(q22;q22)/RUNX1-RUNX1T1 (ASXL1, 6/9, 67%, P = 0.02; ASXL2, 10/17, 59%, P = 0.01). Among these 25 patients, 4 (27%) of 15 patients with t(8;21) and 6 (60%) of 10 patients without t(8;21) relapsed. However, most patients with relapse were rescued using stem cell transplantation irrespective of t(8;21). The overall survival (OS) and event-free survival (EFS) rates showed no differences among pediatric AML patients with t(8;21) and ASXL1 or ASXL2 mutations and ASXL wild-type (5-year OS, 75% vs. 100% vs. 91% and 5-year EFS, 67% vs. 80% vs. 67%). In 106 patients with t(8;21) AML, the coexistence of mutations in tyrosine kinase pathways and chromatin modifiers and/or cohesin complex component genes had no effect on prognosis. These results suggest that ASXL1 and ASXL2 mutations play key roles as cooperating mutations that induce leukemogenesis, particularly in pediatric AML patients with t(8;21), and these mutations might be associated with a better prognosis than that reported previously.

ZNF384-related fusion genes define a subgroup of childhood B-cell precursor acute lymphoblastic leukemia with a characteristic immunotype.

Fusion genes involving ZNF384 have recently been identified in B-cell precursor acute lymphoblastic leukemia, and 7 fusion partners have been reported. We further characterized this type of fusion gene by whole transcriptome sequencing and/or polymerase chain reaction. In addition to previously reported genes, we identified BMP2K as a novel fusion partner for ZNF384 Including the EP300-ZNF384 that we reported recently, the total frequency of ZNF384-related fusion genes was 4.1% in 291 B-cell precursor acute lymphoblastic leukemia patients enrolled in a single clinical trial, and TCF3-ZNF384 was the most recurrent, with a frequency of 2.4%. The characteristic immunophenotype of weak CD10 and aberrant CD13 and/or CD33 expression was revealed to be a common feature of the leukemic cells harboring ZNF384-related fusion genes. The signature gene expression profile in TCF3-ZNF384-positive patients was enriched in hematopoietic stem cell features and related to that of EP300-ZNF384-positive patients, but was significantly distinct from that of TCF3-PBX1-positive and ZNF384-fusion-negative patients. However, clinical features of TCF3-ZNF384-positive patients are markedly different from those of EP300-ZNF384-positive patients, exhibiting higher cell counts and a younger age at presentation. TCF3-ZNF384-positive patients revealed a significantly poorer steroid response and a higher frequency of relapse, and the additional activating mutations in RAS signaling pathway genes were detected by whole exome analysis in some of the cases. Our observations indicate that ZNF384-related fusion genes consist of a distinct subgroup of B-cell precursor acute lymphoblastic leukemia with a characteristic immunophenotype, while the clinical features depend on the functional properties of individual fusion partners.

Hypocellular acute myeloid leukemia treated with bone marrow transplantation.

Hypocellular acute myeloid leukemia (AML) mainly occurs in elderly patients, and is extremely rare in childhood. There is still no established treatment for hypocellular AML. We report the case of an 11-year-old boy with hypocellular AML who was treated successfully with allogenic bone marrow transplantation (allo-BMT). He presented with fever, pallor and pancytopenia. Bone marrow aspiration and biopsy confirmed a diagnosis of hypocellular AML. Although low-dose cytarabine induced reduction of blasts, it did not lead to complete remission. He subsequently received myeloablative conditioning and allo-BMT. Graft-versus-host disease (GVHD) prophylaxis included short-course methotrexate and cyclosporine. Neutrophil engraftment (>5 × 108 /L) and platelet recovery (>10 × 1010 /L) were achieved on days 13 and 27, respectively. He developed acute GVHD of the skin (grade 2), which responded well to treatment with prednisolone. He has remained in complete remission for 5 years since allo-BMT. We consider allo-BMT to be feasible for children with hypocellular AML.

High event-free survival rate with minimum-dose-anthracycline treatment in childhood acute promyelocytic leukaemia: a nationwide prospective study by the Japanese Paediatric Leukaemia/Lymphoma Study Group.

We evaluated the efficacy of treatment using reduced cumulative doses of anthracyclines in children with acute promyelocytic leukaemia (APL) in the Japanese Paediatric Leukaemia/Lymphoma Study Group AML-P05 study. All patients received two and three subsequent courses of induction and consolidation chemotherapy respectively, consisting of all-trans retinoic acid (ATRA), cytarabine and anthracyclines, followed by maintenance therapy with ATRA. Notably, a single administration of anthracyclines was introduced in the second induction and all consolidation therapies to minimize total doses of anthracycline. The 3-year event-free (EFS) and overall survival rates for 43 eligible children were 83·6% [95% confidence interval (CI): 68·6-91·8%] and 90·7% (95% CI: 77·1-96·4%), respectively. Although two patients died of intracranial haemorrhage or infection during induction phases, no cardiac adverse events or treatment-related deaths were observed during subsequent phases. Patients not displaying M1 marrow after the first induction therapy, or those under 5 years of age at diagnosis, showed inferior outcomes (3-year EFS rate; 33·3% (95% CI: 19·3-67·6%) and 54·6% (95% CI: 22·9-78·0%), respectively). In conclusion, a single administration of anthracycline during each consolidation phase was sufficient for treating childhood APL. In younger children, however, conventional ATRA and chemotherapy may be insufficient so that alternative therapies should be considered.

CXCR4 Overexpression is a Poor Prognostic Factor in Pediatric Acute Myeloid Leukemia With Low Risk: A Report From the Japanese Pediatric Leukemia/Lymphoma Study Group.

BACKGROUND: Overexpression of CXC chemokine receptor 4 (CXCR4+) is a poor prognostic factor in adult acute myeloid leukemia (AML); however, its prognostic significance in pediatric AML is unclear. PROCEDURE: This retrospective study examined the prognostic significance of CXCR4+ in pediatric AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 study. RESULTS: In the total cohort (n = 248), no significant differences were observed between CXCR4+ patients (n = 81) and CXCR4- patients (n = 167) in terms of 3-year overall survival (OS) (69.4% vs. 75.2%, P = 0.44). However, there was a significant difference in 3-year OS between CXCR4+ and CXCR4- patients in the low-risk (LR) group (n = 93; 79.2% vs. 98.3%, P = 0.007). CXCR4+ patients in the t(8;21) AML without KIT mutation group had a significantly worse 3-year OS than CXCR4- patients (n = 44; 76.1% vs. 100.0%, P = 0.01). Multivariate Cox regression analysis identified CXCR4+ as a poor prognostic factor for OS in LR AML patients (hazard ratio, 11.47; P = 0.01). Consistent with the data for survival analysis, CXCR4+ patients in the t(8;21) AML group had a higher incidence of splenomegaly than CXCR4- patients (25.9% vs. 5.9%, P = 0.03). CONCLUSIONS: These results suggest that CXCR4+ is a poor prognostic factor for LR patients, particularly t(8;21) patients without KIT mutation. The poor outcome was only applicable to OS, not relapse-free survival (RFS); thus, CXCR4+ may be associated with a poor prognosis after recurrence. Intensive therapy, including administration of CXCR4 antagonists, may be promising for pediatric AML patients with LR.

Preserved High Probability of Overall Survival with Significant Reduction of Chemotherapy for Myeloid Leukemia in Down Syndrome: A Nationwide Prospective Study in Japan.

BACKGROUND: On the basis of results of previous Japanese trials for myeloid leukemia in Down syndrome (ML-DS), the efficacy of risk-oriented therapy was evaluated in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-D05 study. PROCEDURE: All patients received induction chemotherapy that consisted of pirarubicin, intermediate-dose cytarabine, and etoposide. Patients who achieved complete remission (CR) after initial induction therapy were stratified to the standard risk (SR) group and received four courses of reduced-dose intensification therapy. Patients who did not achieve CR were stratified to the high risk (HR) group and received intensified therapy that consisted of continuous or high-dose cytarabine. RESULTS: A total of 72 patients were eligible and evaluated. One patient died of sepsis during initial induction therapy. Sixty-nine patients were stratified to SR and two patients to HR. No therapy-related deaths were observed during intensification therapy. The 3-year event-free and overall survival rates were 83.3% ± 4.4% and 87.5% ± 3.9%, respectively. Age at diagnosis less than 2 years was a significant favorable prognostic factor for risk of relapse (P = 0.009). CONCLUSIONS: The attempt of risk-oriented prospective study for ML-DS was unsuccessful, but despite the dose reduction of chemotherapeutic agents, the overall outcome was good, and further dose reduction might be possible for specific subgroups.

Infective endocarditis associated with acute leukemia: Report of two cases.

There have been few reports regarding infective endocarditis (IE) in patients with leukemia. In the first case, a 15-year-old girl with Down syndrome was diagnosed with acute lymphoblastic leukemia. On admission, methicillin-sensitive Staphylococcus aureus (MSSA) was detected on blood culture. Echocardiography was performed because MSSA was detected repeatedly even after treatment. Vegetation in all of the atria and ventricles met the Duke criteria defining IE. She died of multiple organ failure 21 days after diagnosis. In the second case, an 11-year-old boy with acute myeloid leukemia underwent peripheral blood stem cell transplantation (PBSCT). He had fever 68 days after PBSCT, and methicillin-resistant S. aureus (MRSA) was detected on blood culture. Echocardiography showed vegetation in the right atrium and ventricle. Daptomycin was administered for 7 weeks, and recurrence was not observed. IE should be considered when S. aureus bacteremia is documented even in patients with leukemia.

No impact of high-dose cytarabine and asparaginase as early intensification with intermediate-risk paediatric acute lymphoblastic leukaemia: results of randomized trial TCCSG study L99-15.

The Tokyo Children's Cancer Study Group conducted a randomized controlled study to evaluate the effect of experimental early intensification using high-dose cytarabine and L-asparaginase in paediatric intermediate-risk (IR) acute lymphoblastic leukaemia (ALL). A total of 310 IR ALL patients were randomized to receive either experimental early intensification (n = 156) or standard early intensification including standard-dose cytarabine arm (n = 154) after induction therapy. The experimental arm consisted of high-dose cytarabine and L-asparaginase, while the standard arm consisted of standard-dose cytarabine, oral 6-mercaptopurine and cyclophosphamide. The probabilities of event-free survival at 8 years in the experimental and standard arms were 72·3 ± 3·7% and 77·5 ± 3·5%, respectively (P = 0·32). The 8-year overall survival rates for these two arms were 85·0 ± 3·0% and 86·9 ± 2·8%, respectively (P = 0·72). The frequency of infectious events was significantly higher in the experimental arm (66·4%) than in the standard arm (24·6%) (P < 0·001). In conclusion, experimental early intensification including high-dose cytarabine followed by L-asparaginase had no advantage over standard early intensification in paediatric IR ALL patients.

Acute myeloid leukaemia with myelodysplastic features in children: a report of Japanese Paediatric Leukaemia/Lymphoma Study Group.

The clinical characteristics and prognostic relevance of acute myeloid leukaemia (AML) with myelodysplastic features remains to be clarified in children. We prospectively examined 443 newly diagnosed patients in a multicentre clinical trial for paediatric de novo AML, and found 'AML with myelodysplasia-related changes' (AML-MRC) according to the 2008 World Health Organization classification in 93 (21·0%), in whom 59 were diagnosed from myelodysplasia-related cytogenetics alone, 28 from multilineage dysplasia alone and six from a combination of both. Compared with 111 patients with 'AML, not otherwise specified' (AML-NOS), patients with 'AML-MRC' presented at a younger age, with a lower white blood cell count, higher incidence of 20-30% bone marrow blasts, unfavourable cytogenetics and a lower frequency of Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD), NPM1 and CEBPA mutations. Complete remission rate and 3-year probability of event-free survival were significantly worse in 'AML-MRC' patients (67·7 vs. 85·6%, P < 0·01, 37·1% vs. 53·8%, P = 0·02, respectively), but 3-year overall survival and relapse-free survival were comparable with 'AML-NOS' patients. By multivariate analysis, FLT3-ITD was solely associated with worse overall survival. These results support the distinctive features of the category 'AML-MRC' even in children.

Clinical characteristics and outcome of refractory/relapsed myeloid leukemia in children with Down syndrome.

Myeloid leukemia in Down syndrome (ML-DS) is associated with good response to chemotherapy and favorable prognosis. Because little research has been focused on refractory/relapsed (R/R) cases, we conducted a retrospective analysis for R/R ML-DS. Among ML-DS patients diagnosed between 2000 and 2010 in Japan, 26 relapsed (25 in the BM and 1 in the skin), and 3 refractory patients were enrolled. The male/female ratio was 18/11. The median age at initial diagnosis of ML-DS was 2 years, and the median time to relapse was 8.6 months. Each patient initially had been treated with ML-DS-specific protocols. Thirteen of the 26 patients achieved complete remission with various kinds of reinduction chemotherapies; 2 of 8 survived without further recurrence after receiving allogeneic hematopoietic stem cell transplantation, and 4 of 5 maintained complete remissions with chemotherapy alone. Treatment failures mostly were associated with disease progression rather than treatment-related toxicities. The 3-year OS rate was 25.9% ± 8.5%. A longer duration from initial diagnosis to relapse was a significant favorable prognostic factor (P < .0001). We conclude that clinical outcome for patients with R/R ML-DS generally are unfavorable, even in those receiving hematopoietic stem cell transplantation. Novel methods to identify poor prognostic factors for ML-DS are necessary.

Diagnosis and management of acute myeloid leukemia in children and adolescents: recommendations from an international expert panel.

Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼70%. State-of-the-art recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.