Prognostic factors in infants with acute myeloid leukemia

Long noncoding RNAs as regulators of pediatric acute myeloid leukemia

Long noncoding RNAs (lncRNAs) are increasingly emerging as regulators across human development and disease, and many have been described in the context of hematopoiesis and leukemogenesis. These studies have yielded new molecular insights into the contribution of lncRNAs to AML development and revealed connections between lncRNA expression and clinical parameters in AML patients. In this mini review, we illustrate the versatile functions of lncRNAs in AML, with a focus on pediatric AML, and present examples that may serve as future therapeutic targets or predictive factors.

Whole exome sequencing of pediatric leukemia reveals a novel InDel within FLT-3 gene in AML patient from Mizo tribal population, Northeast India

Background

Leukemia is the most common type of cancer in pediatrics. Genomic mutations contribute towards the molecular mechanism of disease progression and also helps in diagnosis and prognosis. This is the first scientific mutational exploration in whole exome of pediatric leukemia patients from a cancer prone endogamous Mizo tribal population, Northeast India.

Result

Three non-synonymous exonic variants in NOTCH1 (p.V1699E), MUTYH (p.G143E) and PTPN11 (p.S502P) were found to be pathogenic. A novel in-frame insertion-deletion within the juxtamembrane domain of FLT3 (p.Tyr589_Tyr591delinsTrpAlaGlyAsp) was also observed.

Conclusion

These unique variants could have a potential mutational significance and these could be candidate genes in elucidating the possibility of predisposition to cancers within the population. This study merits further investigation for its role in diagnosis and prognosis and also suggests the need for population wide screening to identify unique mutations that might play a key role towards precision medicine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01037-x.

Successful Bone Marrow Transplantation With Intensive Post-transplant Intrathecal Chemotherapy for CNS Relapsed AML in 2 Infants

BACKGROUND

Infant acute myeloid leukemia is a rare but aggressive form of leukemia.

OBSERVATION

We report 2 children who presented with hyperleukocytosis, subsequently diagnosed with infant acute myeloid leukemia, and both developed isolated central nervous system relapse while on chemotherapy. Both infants underwent successful bone marrow transplantation with myeloablative conditioning (thiotepa, busulfan, and cyclophosphamide) without radiation, followed by 12 empiric post-transplant lumbar punctures with intrathecal cytarabine. Both patients tolerated these therapies well, and are without infections, chronic graft-versus-host disease, or any post-transplant sequelae.

CONCLUSION

Nonradiation-based conditioning followed by empiric central nervous system-directed intrathecal chemotherapy may be considered for high-risk infants with leukemia.

Presentation acuity, induction mortality, and resource utilization in infants with acute leukemia

BACKGROUND

Treatment of infants with acute leukemia remains challenging, especially for acute lymphocytic leukemia (ALL). Infants have shown markedly higher rates of induction mortality compared with noninfants. There are limited data on presentation acuity and supportive care utilization in this age group.

METHODS

In retrospective analyses of patients treated for new onset ALL or acute myeloid leukemia (AML) at pediatric hospitals contributing to the Pediatric Health Information System, we compared presentation acuity, induction mortality, and resource utilization in infants relative to noninfants less than 10 years at diagnosis.

RESULTS

Analyses included 10 359 children with ALL (405 infants, 9954 noninfants) and 871 AML (189 infants, 682 noninfants). Infants were more likely to present with multisystem organ failure compared to noninfants for both ALL (12% and 1%, PR = 10.8, 95% CI: 7.4, 15.7) and AML (6% vs. 3%; PR = 2.0, 95% CI: 1.0, 3.7). Infants with ALL had higher induction mortality compared to noninfants, even after accounting for differences in anthracycline exposure and presentation acuity (2.7% vs. 0.5%, HR = 2.1, 95% CI: 1.0, 4.8). Conversely, infants and noninfants with AML had similar rates of induction mortality (3.2% vs. 2.1%, HR = 1.2, 95% CI: 0.3, 3.9), which were comparable to rates among infants with ALL. Infants with ALL and AML had greater requirements for blood products, diuretics, supplemental oxygen, and ventilation during induction relative to noninfants.

CONCLUSIONS

Infants with leukemia present with higher acuity compared with noninfants. Induction mortality and supportive care requirements for infants with ALL were similar to all children with AML, and significantly higher than those for noninfants with ALL.

Acute Leukemia in Infants

PURPOSE OF THE REVIEW

Infant leukemia is a rare, distinct subgroup of pediatric acute leukemias diagnosed in children under 1 year of age and characterized by unique, aggressive biology. Here, we review its clinical presentation, underlying molecular biology, current treatment strategies, and novel therapeutic approaches.

RECENT FINDINGS

Infant leukemias are associated with high-risk molecular features and high rates of chemotherapy resistance. International collaborative clinical trials have led to better understanding of the underlying molecular biology, refined risk-based stratification, and investigated the use of hematopoietic stem cell transplantation. However, intensification of chemotherapy has failed to improve outcomes, and current regimens are associated with significant treatment-related and long-term toxicities. Infants with leukemia remain a challenging group to treat. We must continue collaborative efforts to move beyond traditional cytotoxic chemotherapy, incorporate molecularly targeted strategies and immunotherapy, and increase access to clinical trials to improve outcomes for this high-risk group of patients.

Is Acute Myeloblastic Leukemia in Children Under 2 Years of Age a Specific Entity? A Report from the FRENCH ELAM02 Study Group

The clinical and biological characteristics of children under 2 years (infants) with acute myeloid leukemia (AML) are different from those of older children. We aimed to describe the specific characteristics of this population and the potential factors that influence the prognosis. We analyzed data concerning 438 children with newly-diagnosed AML treated in the ELAM02 protocol between March 2005 and December 2011, of which 103 were under 2 years old at diagnosis. The evaluation criteria were overall survival (OS) and event-free survival (EFS) of infants vs older children. The clinical and biological features were secondary criteria. Infants presented more frequent extra-medullary presentation than older children. They had a significantly higher proportion of skin lesions and central nervous system involvement (15% vs 3%, p < 0.0001 and 26% vs 12%, p = 0.0005, respectively). The global incidence of KMT2A rearrangements was nearly 55% for infants vs 11% for older children (p < 0.0001). Median 5-year OS was 70.4% for infants vs 71.4% for older children (p = 0.83). Five-year EFS was 67% for infants vs 58% for older children (p = 0.27). Infants with AML represent a cohort of patients with specific clinical and biological features. These remarkable differences had no significant impact on their outcome in the ELAM02 protocol.

Prenatally Diagnosed Infant AML

We report the first case of a fetus with acute myeloid leukemia, without Down syndrome, diagnosed in utero. A cordocentesis sample prepared to investigate hepatomegaly led to further evaluations revealing acute myeloid leukemia, monocytic type, in the fetus. Cytogenetic analysis showed mixed lineage leukemia duplication, no gene disruption or trisomy. Planned treatment included intrauterine exchange transfusion to extend gestation, low-dose chemotherapy at birth, and full chemotherapy once stable. Before any intervention, the child was delivered emergently for maternal condition and died 2 hours later. Although it is now possible to diagnose hematologic malignancy in a fetus, there is little information to direct management.

Improved outcome of childhood acute myeloid leukemia in an Eastern European country: Lithuanian experience

The reported treatment outcomes of children treated for cancer in Eastern European countries are inferior to those in Northern/Western Europe. We hypothesized that recent survival rates could be comparable to the current standards and performed a population-based analysis of treatment outcome of childhood acute myeloid leukemia (AML) in Lithuania, a small Eastern European country. Children < 18 years old who were treated for AML from 2000 to 2013 were included (n = 54). Estimates of 5-year event-free (EFS_5y) and overall survival (OS_5y) rates were analyzed. Comparing periods 2000-2006 (n = 32) and 2007-2013 (n = 22), the EFS_5y improved from 31 to 63% (p = 0.04), and the OS_5y improved from 31 to 72% (p = 0.02) because of reductions in toxicity-related mortality (42 vs. 15%, p = 0.08) and relapse (43 vs. 25%, p = 0.08). The most significant improvement was demonstrated in high-risk patients (OS_5y improved from 26 to 75%, p = 0.02) who benefited from hematopoietic stem cell transplantation: the post-transplant EFS_5y increased from 13 to 86% (p = 0.01).

CONCLUSIONS

The current survival rate of Lithuanian children treated for AML was comparable to the expected rate in other parts of Europe. What is Known: • In the last three decades, significant improvement has been achieved in treating childhood cancer, with an overall survival (OS) rate of > 80% in high-income countries. The difference in survival rates between Northern/Western and Eastern European countries as well as between high- and middle-/low-income countries is as much as 20%. Recently, the 5-year event-free survival rate of acute myeloid leukemia (AML) has reached > 60% in high-income countries. The survival rates for myeloproliferative diseases were the lowest in Eastern European countries. • The reported inferior survival rates were calculated based on outcome data of patients treated until 2007. The recent survival rates in Eastern European countries are unknown. What is New: • Being a small Eastern European country, Lithuania has experienced good economic growth during the last decade. We hypothesized that economic growth and gain of experience could result in better survival rates of children treated for cancer in our country in recent years. • A population-based analysis of treatment outcome of childhood AML treated in Lithuania in the recent years was performed for the first time. The survival rates of childhood AML in Lithuania are comparable to those of other high-income countries. Current survival rates of children treated for cancer in Eastern European countries could be comparable to the best current standards contributing to better European survival rates of childhood cancer in general.

ZFP521 regulates murine hematopoietic stem cell function and facilitates MLL-AF9 leukemogenesis in mouse and human cells

The concept that tumor-initiating cells can co-opt the self-renewal program of endogenous stem cells as a means of enforcing their unlimited proliferative potential is widely accepted, yet identification of specific factors that regulate self-renewal of normal and cancer stem cells remains limited. Using a comparative transcriptomic approach, we identify ZNF521/Zfp521 as a conserved hematopoietic stem cell (HSC)-enriched transcription factor in human and murine hematopoiesis whose function in HSC biology remains elusive. Competitive serial transplantation assays using Zfp521-deficient mice revealed that ZFP521 regulates HSC self-renewal and differentiation. In contrast, ectopic expression of ZFP521 in HSCs led to a robust maintenance of progenitor activity in vitro. Transcriptional analysis of human acute myeloid leukemia (AML) patient samples revealed that ZNF521 is highly and specifically upregulated in AMLs with MLL translocations. Using an MLL-AF9 murine leukemia model and serial transplantation studies, we show that ZFP521 is not required for leukemogenesis, although its absence leads to a significant delay in leukemia onset. Furthermore, knockdown of ZNF521 reduced proliferation in human leukemia cell lines possessing MLL-AF9 translocations. Taken together, these results identify ZNF521/ZFP521 as a critical regulator of HSC function, which facilitates MLL-AF9-mediated leukemic disease in mice.

Clinical characteristics of patients with central nervous system relapse in BCR-ABL1-positive acute lymphoblastic leukemia: the importance of characterizing ABL1 mutations in cerebrospinal fluid

We investigated the frequency, predictors, and evolution of acute lymphoblastic leukemia (ALL) in patients with CNS relapse and introduced a novel method for studying BCR-ABL1 protein variants in cDNA from bone marrow (BM) and cerebrospinal fluid (CSF) blast cells. A total of 128 patients were analyzed in two PETHEMA clinical trials. All achieved complete remission after imatinib treatment. Of these, 30 (23%) experienced a relapse after achieving complete remission, and 13 (10%) had an isolated CNS relapse or combined CNS and BM relapses. We compared the characteristics of patients with and without CNS relapse and further analyzed CSF and BM samples from two of the 13 patients with CNS relapse. In both patients, classical sequencing analysis of the kinase domain of BCR-ABL1 from the cDNA of CSF blasts revealed the pathogenic variant p.L387M. We also performed ultra-deep next-generation sequencing (NGS) in three samples from one of the relapsed patients. We did not find the mutation in the BM sample, but we did find it in CSF blasts with 45% of reads at the time of relapse. These data demonstrate the feasibility of detecting BCR-ABL1 mutations in CSF blasts by NGS and highlight the importance of monitoring clonal evolution over time.

Acute myeloid leukemia in infants: biology and treatment

Children aged 0-2 years (i.e., infants) with acute myeloid leukemia (AML) are a peculiar subgroup of patients in the childhood AML scenario. They present with distinctive biological and clinical characteristics, including a high prevalence of prognostically unfavorable risk factors and an increased susceptibility to therapy-related toxicity. Remarkable improvements have been achieved over the last two decades in the treatment of these patients and their outcome is becoming superimposable to that of the older age groups. In this review, we will focus on peculiarities of this young subgroup of children with AML, describing their clinical presentation, the biology of disease, and factors influencing outcome. Treatment results and toxicity data reported by major collaborative groups are also summarized and compared.

Circulating Blasts Following Chemotherapy in Pediatric Patients: Implications for Complete Remission Definition in Acute Leukemia

We assessed the incidence of circulating blasts occurring post-chemotherapy in 1000 consecutive pediatric blood samples. Blasts with myeloid morphology (<1-3%) were present in post-chemotherapy samples in 19 of 294 (6.4%) patients with acute leukemia in remission and in 11 of 361 (3.4%) patients with solid tumors, non-Hodgkin or Hodgkin lymphoma, and were associated with ANC>1.5x10(9)/l in 13 of 30 (43%) samples, and platelets >100x10(9)/l in 25 of 30 (83%) samples. Our findings suggest that the absence of circulating blasts may not be a prerequisite for remission in acute myeloid leukemia (AML).

Identification of somatic and germline mutations using whole exome sequencing of congenital acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) diagnosed within the first month of life is classified as congenital ALL and has a significantly worse outcome than ALL diagnosed in older children. This suggests that congenital ALL is a biologically different disease, and thus may be caused by a distinct set of mutations. To understand the somatic and germline mutations contributing to congenital ALL, the protein-coding regions in the genome were captured and whole-exome sequencing was employed for the identification of single-nucleotide variants and small insertion and deletions in the germlines as well as the primary tumors of four patients with congenital ALL.

Methods

Exome sequencing was performed on Illumina GAIIx or HiSeq 2000 (Illumina, San Diego, California). Reads were aligned to the human reference genome and the Genome Analysis Toolkit was used for variant calling. An in-house developed Ensembl-based variant annotator was used to richly annotate each variant.

Results

There were 1–3 somatic, protein-damaging mutations per ALL, including a novel mutation in Sonic Hedgehog. Additionally, there were many germline mutations in genes known to be associated with cancer predisposition, as well as genes involved in DNA repair.

Conclusion

This study is the first to comprehensively characterize the germline and somatic mutational profile of all protein-coding genes patients with congenital ALL. These findings identify potentially important therapeutic targets, as well as insight into possible cancer predisposition genes.

Favorable outcome in infants with AML after intensive first- and second-line treatment: an AML-BFM study group report

Infants <1 year of age have a high prevalence of prognostically unfavorable leukemias and a presumed susceptibility to treatment-related toxicities. A total of 125 infants with acute myeloid leukemia (AML) were treated in studies AML-BFM-98 (n = 59) and -2004 (n = 66). Treatment regimens of both studies were comparable, consisting of intensive induction followed by four courses (mainly high-dose cytarabine and anthracyclines). Allogeneic-hematopoietic stem-cell-transplantation (allo-HSCT) in 1st remission was optional for high-risk (HR) patients. Most infants (120/125=96%) were HR patients according to morphological, cytogenetic/molecular genetic and response criteria. Five-year overall survival was 66 ± 4%, and improved from 61 ± 6% in study-98 to 75 ± 6% in study-2004 (P(logrank) 0.14) and event-free survival rates were 44 ± 6% and 51 ± 6% (P(logrank) 0.66), respectively. Results in HR infants were similar to those of older HR children (1-<2- or 2-<10-year olds, P(logrank) 0.90 for survival). Survival rates of HSCT in 1st remission, initial partial response and after relapse were high (13/14, 2/8 and 20/30 patients, respectively). The latter contributes to excellent 5-year survival after relapse (50±8%). Despite more severe infections and pulmonary toxicities in infants, treatment-related death rate was identical to that of older children (3%). Our data indicate that intensive frontline and relapse AML treatment is feasible in infants, toxicities are manageable, and outcome is favorable.

The presence of central nervous system disease at diagnosis in pediatric acute myeloid leukemia does not affect survival: a Children's Oncology Group study

BACKGROUND

The presence of central nervous system (CNS) disease in pediatric acute myeloid leukemia (AML) is often thought to confer a worse prognosis. This study examined the outcome of children with AML who had CNS disease at diagnosis.

METHODS

Patients enrolled on Children's Cancer Group protocols 2861, 2891, 2941, and 2961 being treated for de novo AML were classified for the presence of CNS disease at diagnosis as CNS1 (<5 WBC in the CSF without blasts), CNS2 (<5 WBC in the CSF with blasts), or CNS3 (> or =5 WBC in the CSF with blasts). CNS disease at diagnosis was then analyzed regarding patient characteristics and outcome.

RESULTS

There was an incidence of CNS disease (i.e., CNS3 status) of 11% in the 1,459 patients analyzed in this study. The risk factors found are young age, high white cell count, hepatomegaly or splenomegaly at diagnosis, M4 subtype, chromosome 16 abnormalities, and hyperdiploid cytogenetics. There were no significant differences in overall survival, event free survival, or remission rates between the groups; however, a significant difference was seen between the CNS1 and CNS3 groups in disease free survival and isolated CNS relapse risk.

CONCLUSIONS

Patients with CNS disease at diagnosis have similar survival to those without CNS disease, although they have an increased incidence of isolated CNS relapse. Patients with CNS disease at diagnosis may warrant more aggressive CNS directed therapy.

Cytogenetics of Childhood Acute Myeloid Leukemia: United Kingdom Medical Research Council Treatment Trials AML 10 and 12

Purpose

Karyotype is an independent indicator of prognosis in acute myeloid leukemia (AML) that is widely applied to risk-adapted therapy. Because AML is rare in children, the true prognostic significance of individual chromosomal abnormalities in this age group remains unclear.

Patients and Methods

This cytogenetic study of 729 childhood patients classified them into 22 subgroups and evaluated their incidence and risk.

Results

Rearrangements of 11q23 were the most frequent abnormality found in approximately 16% of patients, with 50% of these in infants. The outcome for all patients with 11q23 abnormalities was intermediate; no difference was observed for those with t(9;11)(p21-22;q23). The core binding factor leukemias with the translocations t(8;21)(q22;q22) and inv(16)(p13q22) occurred at incidences of 14% and 7%, respectively, predominantly in older children, and their prognosis was favorable. An adverse outcome was observed in patients with monosomy 7, abnormalities of 5q, and t(6;9)(p23;q34). Abnormalities of 3q and complex karyotypes, in the absence of favorable-risk features, have been associated with an adverse outcome in adults, but the results were not significant in this childhood series. However, the presence of 12p abnormalities predicted a poor outcome.

Conclusion

Because the spectrum of chromosomal changes and their risk association seem to differ between children and adults with AML, biologic differences are emerging, which will contribute to the redefinition of risk stratification for different age groups in the future.

A new chromosomal three-way rearrangement involving MLL masked by a t(9;19)(p11;p13) in an infant with acute myeloid leukemia

Infants diagnosed with acute myelogenous leukemia (AML) are likely to have subtypes M4 or M5 characterized by 11q23 abnormalities like a t(9;11)(p22;q23). Detection of all possible types of chromosomal abnormalities, including mixed lineage leukemia (MLL) gene rearrangements at 11q23, is of importance for the identification of biological subgroups, which might differ in drug resistance and/or clinical outcome. Here, we report the clinical, conventional banding and molecular cytogenetics data of a 6-month-old boy with an AML-M5 presenting with a unique cryptic rearrangement involving the MLL gene: a three-way t(9;19;11)(p11.2;p13.1;q23).

Allogeneic hematopoietic stem-cell transplantation for myeloid sarcoma: a retrospective study from the SFGM-TC

PURPOSE

This retrospective multicenter study assessed the outcome of 51 patients with myeloid sarcoma (MS) who underwent allogeneic hematopoietic stem-cell transplantation (alloHSCT).

PATIENTS AND METHODS

Most patients had MS presenting in conjunction with acute myeloid leukemia (AML) or after AML. Six patients had isolated MS. The median time between diagnosis and alloHSCT was 8 months (range, 2.8 to 67). Forty patients were in complete remission (CR) at time of alloHSCT.

RESULTS

With a median follow-up of 33 (range, 1 to 182) months, the Kaplan-Meier estimates of overall survival (OS) and disease-free survival were 47% (95% CI, 33% to 61%) and 36% (95% CI, 24% to 50%) at 5 years. Twenty patients (39%) relapsed at a median of 204 (range, 35 to 1151) days after alloHSCT, with relapse being the major cause of death. In a Cox multivariate analysis, age > or = 15 years and remission status at time of alloHSCT (CR v other) were associated with improved OS (hazard ratio [HR], 0.27; 95% CI, 0.12 to 0.65; P = .003; and HR, 0.22; 95% CI, 0.08 to 0.57; P = .002, respectively).

CONCLUSION

We conclude that first-line alloHSCT performed early in the course of MS is a valid therapeutic option.

Banding and molecular cytogenetic studies detected a CBFB-MYH11 fusion gene that appeared as abnormal chromosomes 1 and 16 in a baby with acute myeloid leukemia FAB M4-Eo

The acute myeloid leukemia (AML) subtype M4Eo occurs in 5% of all AML cases and is usually associated with either an inv(16)(p13.1q22) or a t(16;16)(p13.1;q22) chromosomal abnormality. At the molecular level, these abnormalities generate a CBFB-MYH11 fusion gene. Patients with this genetic alteration are usually assigned to a low-risk group and thus receive standard chemotherapy. AML-M4Eo is rarely found in infants. We describe clinical, conventional banding, and molecular cytogenetic data for a 12-month-old baby with AML-M4Eo and a chimeric CBFB-MYH11 fusion gene masked by a novel rearrangement between chromosomes 1 and 16. This rearrangement characterizes a new type of inv(16)(p13.1q22) masked by a chromosome translocation.

Establishment of a novel childhood acute myeloid leukaemia cell line, KOPM-88, containing partial tandem duplication of the MLL gene and an in vivo model for childhood acute myeloid leukaemia using NOD/SCID mice

MLL gene rearrangement is common in both adult and childhood acute myeloid leukaemia (AML), and its role in oncogenesis has been investigated. While over 50 translocated-partner genes have been identified so far, few studies have detailed the molecular mechanism of partial tandem duplication (PTD) of the MLL gene. The prognostic impact and contribution to leukaemogenesis of MLL-PTD, especially in childhood cases, remain unknown. We have established a novel cell line containing MLL-PTD derived from an 11-year-old patient with AML and designated as KOPM-88. KOPM-88 cells exhibited certain characteristics associated with the myeloid lineage including abundant primary granules in the cytoplasm and the expression of myeloperoxidase. The cell growth of KOPM-88 was cytokine independent but was accelerated by granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. MLL-PTD of exon 2 to exon 6 and exon 2 to exon 8 was revealed using Southern blotting, fluorescence in situ hybridisation, and reverse transcription polymerase chain reaction/DNA sequencing. Furthermore, non-obese diabetic/severe combined immunodeficient mice inoculated with KOPM-88 cells exhibited leukaemic infiltrations in the bone marrow and hemiparalysis because of compression myelopathy. This is the first report of an in vivo animal model exhibiting the systemic involvement of childhood AML containing MLL-PTD. KOPM-88 cells and our murine model may be useful for investigating the pathogenesis of childhood AML associated with MLL gene rearrangement.

Features and outcome of neonatal leukemia in Japan: experience of the Japan infant leukemia study group

BACKGROUND

Neonatal leukemia characterized by early stem cell origin and extramedullary infiltration in the first 4 weeks of life is rare. We analyzed the features and outcome of neonatal leukemia in Japan to establish an appropriate treatment strategy for this rare disorder.

PROCEDURE

Patients with infant leukemia registered and treated in the Japan Infant Leukemia Study between 1996 and 2001 were analyzed.

RESULTS

Among 162 infant leukemia patients, 11 exhibited neonatal leukemia; frequencies for all infant leukemias were 6.9% (8/116) for acute lymphoblastic leukemia (ALL) and 7.3% (3/41) for acute myeloid leukemia (AML). Positive MLL gene rearrangement was observed in all eight patients with ALL; a single patient with AML displayed germline configuration. Acute monoblastic leukemia was apparent in all three patients with AML (M5a in the FAB classification). Most of the patients demonstrated hepatoplenomegaly and hyperleukocytosis at diagnosis. Cutaneous and central nervous system involvement were detected in half of the patients. Four patients (one with AML, and three with ALL) have survived following stem cell transplantation (SCT); however, growth impairment related to SCT was observed in these patients.

CONCLUSIONS

These results suggest an improvement attributable to treatment of neonatal leukemia. International-based collaborative studies are necessary to investigate the biology of this condition and to establish appropriate therapeutic strategies.

Long-term results in children with AML: NOPHO-AML Study Group--report of three consecutive trials

In all, 447 children with acute myeloid leukaemia (AML) have been treated on three consecutive NOPHO studies from July 1984 to December 2001. NOPHO-AML 84 was of moderate intensity with an induction of three courses of cytarabine, 6-thioguanine and doxorubicin followed by four consolidation courses with high-dose cytarabine. The 5-year event-free survival (EFS), disease free survival (DFS) and overall survival (OS) were 29, 37 and 38%. NOPHO-AML 88 was of high intensity with the addition of etoposide and mitoxantrone in selected courses during induction and consolidation. The interval between the induction courses should be as short as possible, that is, time intensity was introduced. The 5-year EFS, DFS and OS were 41, 48 and 46%. In NOPHO-AML 93, the treatment was stratified according to response to first induction course. The protocol utilised the same induction blocks as NOPHO-AML 88, but after the first block, children with a hypoplastic, nonleukaemic bone marrow were allowed to recover before the second block. Consolidation was identical with NOPHO-AML 88. The 5-year EFS, DFS and OS in NOPHO-AML 93 were 48, 52 and 65%. The new NOPHO-AML protocol has been based on experiences from previous protocols with stratification of patients with regard to in vivo response and specific cytogenetic aberrations.

Comparable Long-Term Survival After Unrelated and HLA-Matched Sibling Donor Hematopoietic Stem Cell Transplantations for Acute Leukemia in Children Younger Than 18 Months

Purpose

To describe outcomes after unrelated donor stem cell transplantation (HCT) in children (< 18 months at diagnosis) with acute leukemia and compare these with outcomes after human leukocyte antigen (HLA)-matched sibling donor HCT.

Patients and Methods

We compared the results of unrelated donor HCT with bone marrow (n = 85) or cord blood grafts (n = 81) and HLA-matched sibling donor HCT with bone marrow grafts (n = 101) for acute myeloid or acute lymphoblastic leukemia using Cox proportional hazards models. Unrelated donor HCT recipients were younger, more likely to have MLL gene rearrangement, to have advanced leukemia, and to receive irradiation before HCT.

Results

Treatment-related mortality rates were 6%, 15%, and 31% after matched sibling, unrelated donor bone marrow, and cord blood HCT, respectively. Risks of relapse, overall and leukemia-free survival were significantly associated with disease status at transplantation. Though leukemia recurrence was lowest after unrelated donor HCT in first clinical remission (CR), overall survival, and leukemia-free survival rates were similar after matched sibling and unrelated donor HCT, after adjustment for disease status. Relapse, overall and leukemia-free survival did not differ by graft type (bone marrow v cord blood) or type of leukemia. Three-year probabilities of leukemia-free survival were 49% and 54% after HLA-matched sibling and unrelated donor transplantation in first CR, respectively. Corresponding rates for those with advanced leukemia were 20% and 30%.

Conclusion

Unrelated donor HCT should be considered for infants with acute leukemia in first CR using the same eligibility criteria as are currently used for those with HLA matched sibling donors.

Risk Factors and Therapy for Isolated Central Nervous System Relapse of Pediatric Acute Myeloid Leukemia

Purpose

CNS relapse of pediatric acute myeloid leukemia (AML) is an infrequent occurrence. This review examines the risk factors and therapy used for patients with an isolated CNS relapse.

Patients and Methods

Records of 886 patients with de novo AML were reviewed, and patients who entered remission at the end of one course of therapy and developed an isolated CNS relapse as their first event were analyzed (n = 690).

Results

Thirty-three patients developed an isolated CNS relapse. Factors at diagnosis significantly associated with an isolated CNS relapse, compared with no CNS relapse, included age 0 to 2 years (70% v 27%, respectively; P < .001), enlarged liver (79% v 39%, respectively; P < .001) or spleen (79% v 39%, respectively; P < .001) at diagnosis, CNS disease at diagnosis (33% v 9%, respectively; P < .001), median WBC count (79.2 v 19.3 × 103 μL, respectively; P < .001), French-American-British M5 morphology (45% v 15%, respectively; P < .001), and chromosome 11 abnormalities (44% v 18%, respectively; P = .022). Treatment of the isolated CNS relapse varied from local therapy with intrathecal chemotherapy and/or radiation therapy to systemic therapy with chemotherapy with or without bone marrow transplantation. Survival rate in the patients treated with local therapy was only 31.5% compared with 21.4% in patients treated with systemic therapy. The 8-year overall survival for patients after an isolated CNS relapse was similar to patients after a bone marrow relapse (26% ± 16% v 21% ± 5%, respectively).

Conclusion

Significant predictors for isolated CNS relapse were identified. This study demonstrated that there may be no benefit to systemic therapy versus CNS-directed therapy in outcome. The data support CNS-directed therapy to treat isolated CNS relapse.

Cellular drug sensitivity in MLL-rearranged childhood acute leukaemia is correlated to partner genes and cell lineage

Rearrangements in the 11q23 region, the site of the mixed lineage leukaemia (MLL) gene, are found in both childhood acute myeloid (AML) and lymphoblastic (ALL) leukaemia. We studied the in vitro drug resistance by the fluorometric microculture cytotoxicity assay (FMCA) in 132 children with AML and 178 children with ALL (aged 0-17 years). In AML, children with t(9;11) (n = 10) were significantly more sensitive to cytarabine (P < 0.001) and doxorubicin (P = 0.005) than non-11q23 rearranged patients (n = 108). Children with other 11q23 rearrangements (n = 14) differed less from non-rearranged children. The 'AML-profile' common to all three groups included relative resistance to glucocorticoids and vincristine. In ALL, children with 11q23 rearrangement (n = 22) were significantly more sensitive to cytarabine (P = 0.026) than children without 11q23 rearrangement (n = 156), also after stratification for white blood cell count. In conclusion, the findings indicate that the cellular drug resistance is correlated to both the cell lineage and the type of 11q23 rearrangement. High cellular sensitivity to cytarabine and doxorubicin might explain the excellent treatment results in children with AML and t(9;11). The present study supports the strategy of contemporary protocols to include high-dose cytarabine in the treatment of 11q23-positive patients both in AML and ALL.

Clinical Aspects of Infant Leukemia-Experiences of a Single Institution of Japan: High Level of Serum Immunoglobulin M in Infant Leukemia

The prognosis and clinical and biological characteristics of infant leukemia differ from those of leukemia in children 1 year or older. We reviewed the charts of patients younger than 1 year in whom leukemia was diagnosed from January 1981 through December 2003 at our institution. Fourteen infants had leukemia, 6 had acute lymphoblastic leukemia (ALL), and 8 had acute myeloid leukemia (AML). The age of patients at diagnosis ranged from 2 to 11 months. Five of 8 AML patients presented with cutaneous manifestations, such as erythema and nodules, at diagnosis. Central nervous system (CNS) involvement was seen in 1 AML patient at diagnosis. Hyperleukocytosis of more than 50 x 10(9)/L was seen in 4 of 6 ALL patients and in 4 of 8 AML patients at diagnosis. All ALL patients showed a morphological diagnosis of L1 using the French-America-British classification system. For patients with AML, the morphological diagnoses were M0 for 1 patient, M2 for 1 patient, M4 for 2 patients (1 with eosinophilia), M5b for 2 patients, and M7 for 2 patients. One patient showing M7 morphology had Down syndrome. Surface markers were examined in 5 of 6 ALL patients and all AML patients. Five ALL patients showed a B-cell precursor immunophenotype. Two of 5 patients with ALL had CD10-positive leukemic cells and 3 of 5 patients with ALL had CD10-negative leukemic cells. All AML patients were positive for CD13 or CD33 or both. Three of 5 patients with ALL showed abnormal chromosomes related to 11q. Six of 7 patients with AML showed abnormal karyotypes. MLL gene rearrangements were seen in 3 (2 ALL, 1 AML) of 5 (2 ALL, 3 AML) patients. Serum immunoglobulin M levels were increased in 9 of 14 patients. Complete remission (CR) was achieved in all infants with ALL. Three patients relapsed and then died of the original disease. One of these 3 patients died after cord blood transplantation. Three ALL patients are alive without leukemia. CR was achieved in 6 of 8 AML patients. Four of 6 patients are alive without leukemia. Infant leukemia patients in our institution had some special features. CNS involvement at diagnosis was seen in only 1 patient and serum IgM levels were higher than those in children whose leukemia was diagnosed at 1 to 10 years of age.

Cytogenetics in acute leukemia

Cytogenetic analyses in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) have revealed a great number of non-random chromosome abnormalities. In many instances, molecular studies of these abnormalities identified specific genes implicated in the process of leukemogenesis. The more common chromosome aberrations have been associated with specific laboratory and clinical characteristics, and are now being used as diagnostic and prognostic markers guiding the clinician in selecting the most effective therapies. Specific chromosome aberrations and their molecular counterparts have been included in the World Health Organization classification of hematologic malignancies, and together with morphology, immunophenotype and clinical features are used to define distinct disease entities. However, the prognostic importance of less frequent recurrent aberrations in AML and ALL, both primary and secondary, is still to be determined. This review summarizes current views on clinical relevance of major cytogenetic findings in adult AML and ALL.

Classical and molecular cytogenetic abnormalities and outcome of childhood acute myeloid leukaemia: report from a referral centre in Israel

The incidence of cytogenetic abnormalities in childhood de novo acute myeloid leukaemia (AML) and its prognostic significance was assessed in an Israeli paediatric referral centre. Cytogenetic analysis was successful in 86 of 97 children (< 20 years of age) diagnosed between 1988 and 2002 with de novo AML. Fluorescence in situ hybridization analysis detected new information in 11 of them, leading to reassignment in cytogenetic group classification. The incidence of the various cytogenetic subgroups was as follows: normal - 9%; t(11q23) - 22%; t(8;21) - 13%; t(15;17) - 8%; inv(16) - 3.4%; abn(3q) - 4.6%; 7/7q-(sole or main) - 5.8%; del(9q)(sole) and +21(sole) - 4.6% each; t(8;16) - 2.3%; t(6;9), t(1;22), +8(sole) - 1.1% each; and miscellaneous - 18%. The overall survival (OS) and event-free survival (EFS) (4 years) for 94 patients treated with the modified Berlin-Frankfürt-Münster (BFM) AML protocols (non-irradiated) were 59.9% (SE = 5%) and 55.7% (SE = 5%), respectively, and for the favourable t(8;21), t(15;17) and inv(16), OS was 60% (SE = 15%), 83% (SE = 15%) and 100% respectively. For the normal group it was 62% (SE = 17%), miscellaneous 64% (SE = 12%), t(11q23) 44.6% (SE = 11%) and of the -7/7q-, del(9q)(sole) or t(6;9), none had survived at 4 years. The incidence of cytogenetic subgroups in the Israeli childhood AML population and their outcome were similar to other recently reported paediatric series. Cytogenetic abnormalities still carry clinical relevance for treatment stratification in the context of modern chemotherapy.

Cryptic insertion ofMLL gene into 9p22 leads toMLL-MLLT3 (AF9) fusion in a case of acute myelogenous leukemia

The formation of a leukemogenic fusion product in hematopoietic malignancies is commonly achieved by chromosomal translocation. Alternate and cytogenetically undetectable mechanisms of fusion transcript generation have been documented for BCR-AB1, AML1-ETO, PML-RARA, NPM/ALK, and MLL-MLLT2 (AF4). Here, we report the investigation of a cryptic rearrangement leading to MLL-MLLT3 transcript formation. Cytogenetic analysis of peripheral blood from a 50-year-old acute myeloid leukemia patient yielded a karyotype of 47,XY,+8,del(11)(q21q23) in all metaphase cells examined. Metaphase fluorescence in situ hybridization analysis using the MLL probe at 11q23 revealed that the 5' portion of the MLL gene was inserted into chromosome 9 at band p22, whereas the 3' region of the MLL gene remained on chromosome 11. Whole-chromosome paint analysis confirmed the cryptic transfer of chromosome 11 material to 9p22. With this information, the karyotype was reassigned as 47,XY,+8,der(9)ins(9;11)(p22;q23q23),del(11)(q21q23). RT-PCR was used to show that the cryptic rearrangement in this patient led to the fusion of the MLL and MLLT3 transcripts on the der(9). The presence of the MLL-MLLT3 transcript is consistent with the clinical findings in this patient.

Rearrangement of the MLL gene and a region proximal to the RARalpha gene in a case of acute myelocytic leukemia M5 with a t(11;17)(q23;q21)

A case of acute myelocytic leukemia (AML) M5 subtype (French-American-British classification), in a 13-year-old girl showed the abnormal karyotype 46,XX,t(11;17)(q23;q21) in all bone marrow cells analyzed. Rearrangements involving 11q23 are frequent in cases of AML M5 and often involve the MLL gene. Nevertheless, t(11;17)(q23;q21) is very rare in this type of leukemia. In acute promyelocytic leukemia, the RARalpha gene, located at 17q21, is involved in almost all cases. Fluorescence in situ hybridization studies revealed a deletion of the C-terminal part of the MLL gene and a translocation of the RARalpha gene on the derivative chromosome 11, proximal to the remaining part of the MLL gene. However, hybridization with the LSI RARA dual color break-apart rearrangement probe showed that the RARalpha gene was not rearranged in this translocation. This is the first study reporting a t(11;17)(q23;q21) with a deletion distal to MLL gene exon 6 in a case of AML M5. Furthermore, this is the second study that strongly suggests the implication of a gene proximal and close to the RARalpha locus in a case of AML M5. According to these results, the discovery of new fusion partner genes of MLL and the precise characterization of t(11;17) will be important for the understanding of neoplastic cell differentiation in AML M5.

Treatment stratification based on initial in vivo response in acute myeloid leukaemia in children without Down's syndrome: results of NOPHO-AML trials

Three consecutive protocols for childhood acute myeloid leukaemia (AML) have been used in the Nordic countries since 1984: the Nordic Society for Paediatric Haematology and Oncology (NOPHO)-AML84 was of moderate intensity, NOPHO-AML88 of high intensity with upfront loading and aggressive consolidation. NOPHO-AML93 utilized the same treatment blocks as NOPHO-AML88, but after the first block those children with a hypoplastic non-leukaemic bone marrow were allowed to recover from aplasia. Poor responders received intensified induction therapy. Between January 1993 and December 2000, 219 children without Down's syndrome were entered on NOPHO-AML93. Compared with NOPHO-AML88, the event-free survival (EFS) at 7 years increased from 41% to 49% (P = 0.06) and 7-year overall survival increased from 47% to 64% (P < 0.01). Toxic death during induction was reduced from 10% to 3%. Survival was similar in patients receiving stem cell transplantation or chemotherapy only in first remission. The major prognostic factors in NOPHO-AML93 were response to therapy and cytogenetics. A total of 67% of patients achieved remission after the first induction course and showed an EFS of 56% compared with 35% in those not in remission (P < 0.01). Cytogenetic results were obtained in 95% of patients. Patients with t(9;11) (p22;q23) (n = 16) experienced a significantly better EFS (86%) than other cytogenetic groups. The overall outcome was improved by employing the previous toxic protocol with different timings, and through individualizing therapy according to the initial response of the patient.

Eye shielding during total body irradiation for bone marrow transplantation in children transplanted for a hematological disorder: risks and benefits

This is a retrospective analysis of 188 children who underwent total body irradiation (TBI) in one or two fractions before bone marrow transplantation (BMT) for a hematological disorder. While 139 children had eye shielding during TBI to decrease cataract formation, 49 did not. The blocks used for shielding caused cylindrical areas of decreased dose intensity in the brain. The aim of the study was to determine if there was an increased risk of relapse in the eyes or in the CNS after shielding of the eyes. The probability and severity of cataract formation with and without shielding were also evaluated. None of the 49 children without shielding had a relapse in their eyes or in the CNS after BMT. Of the children with shielding, none had a relapse in the eyes but two of the 139 (1.4%) had a CNS relapse. The incidence of cataracts without shielding was 90% (19 of 21 evaluable patients), while with shielding it was 31% (20 of 64). Severe cataracts were present in eight of 21 (38%) patients without and two of 64 (3%) patients with shielding. The probability of staying cataract free for at least five years was 0.77 with and 0.33 without shielding, at 8 years it was 0.53 and 0.24 respectively. The relative risk of developing a cataract without shielding vs shielding was three (95% CI=1.5; 5.9). It appears that the incidence of relapse in the eyes and CNS is not increased when the eyes are shielded during TBI. Shielding increased the latency time of cataract formation and decreased the severity of cataracts.

Recent advances in the treatment of infant acute myeloid leukemia

Infant acute myeloid leukemia (AML) of less than 12 months old is generally characterized by a high incidence of acute monoblastic or myelomonoblastic leukemia with hyperleukocytosis and extramedullary involvement. Most of the leukemic cells have 11q23 translocations, which lead to the MLL gene rearrangements. The MLL gene rearrangements occur at a high frequency in monoblastic subtype, hyperleukocytosis or young age in infant AML. Compared with acute lymphoblastic leukemia, however, it remains unknown whether prenatal origin exists in the pathogenesis of infant AML. Recently, the treatment outcome of infant AML has been clarified by two study groups, which confirmed the effect of intensive chemotherapy including repeated cycles of cytarabine and anthracyclines for infant AML. Presence of the MLL gene rearrangements, gender, age and white blood cell count showed no influence on the outcome of infant AML. The allogeneic hematopoietic stem cell transplantation (HSCT) remains the treatment of choice for infant AML when a matched related donor is available. Monitoring of minimal residual disease by real-time PCR is a useful technique to predict the outcome or efficacy of the treatment in infant AML. Although intensive chemotherapy and/or allogeneic HSCT have cured most AML infants, some still relapse and ultimately die. A need remains for future development by exploiting the unusual biologic properties of leukemic progenitor cells expressing the abnormal MLL gene product.

[Cutaneous symptoms revealing a monoblastic leukemia]

Leukemia cutis (LC) are not rare in acute myeloid leukaemia (AML) in children but exceptionally reveal it. Most authors think that they have poor prognosis.

CASE REPORT

We report the case of an infant with isolated cutaneous involvement at the time of diagnosis of leukaemia. Bone marrow aspiration showed AML M5. The child was treated by LAME 91 protocol, arm "infant under one year of age". Complete remission, both in bone marrow and skin, was obtained after induction course. Then the patient received consolidation course and megatherapy followed by autologous bone marrow transplantation. Skin relapse occurred early. The complete remission no. 2 was not obtained by second line treatment: new LC appeared when PMN count increased more than 10(9)/l. Then, the child was treated with oral VP16 but disease progressed with more and more LC, followed by bone marrow relapse. Child's death occurred about one year after diagnosis.

Congenital leukaemia: the Dutch experience and review of the literature

We reviewed Dutch patients and those described in the literature with congenital leukaemia in the past 25 years, with the intention to obtain an overview of the characteristics of this rare disease. Among the 117 patients reviewed, acute myeloid leukaemia (AML) was more frequent (64%) than acute lymphoblastic leukaemia (ALL, 21%). Most patients had a high leukaemic cell load with hepatosplenomegaly, leukaemia cutis and hyperleucocytosis. Cytogenetic abnormalities were found in the majority of the patients tested (72%); 11q23 abnormalities were found in less than half of them (42%). The probability of overall survival at 24 months was only 23%. When congenital AML and ALL were compared, clinical characteristics and overall survival were not significantly different. However, in patients at risk, the probability of event-free survival (EFS) and disease-free survival (DFS) were significantly higher in AML than in ALL, 43% versus 13% and 68% versus 0% respectively. Among the congenital AML cases, six spontaneous remissions have been described. In conclusion, the clinical characteristics of congenital leukaemia differ from those of leukaemia in older children and prognosis is generally poor. Once complete remission is achieved, patients with AML fare better than those with ALL. Chemotherapy for congenital leukaemia needs improvement to increase the sustained remission rate.

Outcome of treatment in childhood acute lymphoblastic leukaemia with rearrangements of the 11q23 chromosomal region

BACKGROUND

The prognosis and optimum treatment of childhood acute lymphoblastic leukaemia (ALL) with abnormalities of chromosomal band 11q23 are controversial. We aimed to identify prognostic factors that might help in planning future therapy, and to assess the effectiveness of haemopoietic stem-cell transplantation in patients with the t(4;11) translocation, which is associated with a particularly poor outcome.

METHODS

We reviewed data on 497 children and young adults who had ALL with various 11q23 abnormalities, including the translocations t(4;11), t(9;11), and t(11;19). All patients were treated with intensive chemotherapy, with or without haemopoietic stem-cell transplantation in first complete remission, by 11 study groups and single institutions from 1983 to 1995.

FINDINGS

Age was the most important prognostic factor. In a Cox's proportional-hazard model stratified by 11q23 abnormalities, infants younger than 1 year fared significantly worse than patients 1 year of age or older (hazard ratio for event-free survival 1 84 [95% CI 1 38-2 47], p=0 0001). Among infants, any category of 11q23 abnormality conferred a dismal outcome, whereas in older patients, t(4;11) and t(9;11) were associated with a worse outcome than were other 11q23 changes. In the largest subgroup--256 patients with t(4;11)--any type of transplantation was associated with significantly worse disease-free survival (1 61 [1 10-2 35], p=0 014) and overall survival (1 76 [1 08-2 45], p=0 004) compared with chemotherapy only. Even transplantation with stem cells from HLA-matched related or HLA-matched unrelated donors tended to be associated with a worse outcome than chemotherapy alone.

INTERPRETATION

The prognosis of acute lymphoblastic leukaemia with an 11q23 abnormality is particularly dismal in infants. Allogeneic transplantation with haemopoietic stem cells from an HLA-matched related donor does not seem to improve the clinical outcome in patients with t(4;11)-positive leukaemia.

11q23 balanced chromosome aberrations in treatment-related myelodysplastic syndromes and acute leukemia: report from an international workshop

Among 511 patients with therapy-related myelodysplastic syndrome or acute leukemia (t-MDS/t-AL) and balanced chromosome aberrations, 162 (32%) had translocations involving 11q23. The recurring translocation partners were 9p22 (48%), 19p13.3 (11%), 19p13.1 (10%), 4q21 (9%), 6q27 (6%), 1p32 (2%), 16p13.1 (2%), 10p13 (1%), and 17q25 (1%); in 9%, the translocations were seen only once. The remaining 349 patients were divided into five subgroups based on the balanced aberration: 21q22, inv(16), t(15;17), Rare, and Unique aberrations. Patients in the 11q23 subgroup had a sole cytogenetic abnormality more often than those in the 21q22, inv(16), Rare, and Unique subgroups, and a complex karyotype or -5/del(5q) and/or -7/del(7q) less often than patients in the 21q22, Rare, and Unique subgroups. Clinically, 11q23 patients had acute lymphoblastic leukemia (ALL) more often as their primary disease and a shorter latency from start of treatment for the primary disease to their t-MDS/t-AL diagnosis, except when compared with the inv(16) subgroup. The 11q23 subgroup demonstrated a younger age at t-MDS/t-AL diagnosis, but this finding was not significant when patients with AL as their primary diagnosis were excluded. Survival from the time of diagnosis of t-MDS/t-AL was significantly shorter for the 11q23 subgroup compared with that of the 21q22, inv(16), and t(15;17) subgroups (median 8 vs. 14, 28, and 29 months, respectively). Inferior survival occurred even though 11q23 patients were younger and more often received blood or marrow transplantation (BMT). Even among patients receiving BMT, 11q23 patients had a shorter median survival (9 vs. 12-31 months for the other subgroups). However, among 11q23 patients, those receiving BMT survived longer, with 1- and 5-year survivals of 43% and 18% compared with 23% and 7% for patients not transplanted. With regard to prior therapy, 11q23 patients, compared with other patients, received radiotherapy less often as their sole therapy and chemotherapy more often. They had received VP16, methotrexate, 6MP/6TG, L-asparaginase, daunorubicin, cytarabine, and VM26 more often, likely attributed to the high frequency of AL as their primary disease. More patients in the 11q23 subgroup had received doxorubicin, except in comparison with the 21q22 subgroup; more vincristine, except in comparison with the Rare and Unique subgroups; and more prednisone, except in comparison with the Unique subgroup. Patients in the 11q23 subgroup more often received alkylating agents (AAs) (86% vs. 59-82% for the other subgroups), and topoisomerase II inhibitors (TIs) (84% vs. 49-75%), and they more often reported exposure to AAs plus TIs without radiotherapy (33% vs. 12-21%), except in comparison with the 21q22 subgroup (36%). We performed a multivariate analysis to determine whether the adverse survival of 11q23 patients compared to other Workshop patients was explained by factors other than the presence of the 11q23 abnormality. Covariates in the final model were the five cytogenetic subgroup indicators, where the 11q23 subgroup was the referent (P < 0.0001); age at t-MDS/t-AL (P = 0.0036); previous exposure to lomustine (P < 0.0001) and mitoxantrone (P = 0.0225); BMT for t-MDS/t-AL (P = 0.0006); and karyotype complexity (P = 0.0114). The risk of death for 11q23 patients relative to patients in the 21q22, inv(16), t(15;17), and Unique subgroups was significant, even after adjustment for other risk factors (relative risks 2.3, 3.6, 3.1, and 1.5, respectively; P < 0.0001 for the first three comparisons and P = 0.0125 for the last). When a multivariable model was constructed, excluding patients with AL or MDS as their primary diagnosis, the relative risk of death for 11q23 patients was significantly higher than that of all five other cytogenetic subgroups. We conclude that among t-MDS/t-AL patients with balanced aberrations, 11q23 translocations are an independent adverse risk factor. Although BMT is the current therapy of choice, new treatment is required.

Isolated myelosarcoma in children--update and review

Primary myelosarcomas, also called leukemia cutis, granulocytic sarcomas or chloromas, are rare extramedullary manifestations of acute myeloid leukemia (AML) which precede bone marrow involvement. Skin infiltration was the most frequent localization associated with a myelomonocytic differentiation. Although first remission was achieved by most children, risk of relapse seemed to be increased. This might be caused by the specific biology of myelosarcomas, but also may be the result of delayed or reduced treatment. During the AML-BFM-studies 87/93/98 (11/1987-7/2000) 37 children with isolated myelosarcomas were diagnosed. Eighteen of the 37 patients survived with a 5-year overall survival estimation of 0.54+/-0.09 compared to 0.59+/-0.02; p(log rank) = 0.94. However, reduced or delayed treatment in 17 children led to an increased relapse rate of 71% compared to 35% in children treated soon after diagnosis. The 5-year overall survival in these patients was 0.41+/-0.11. According to our experience and review of the literature, an early diagnostic workup is needed in children with unusual skin lesions or tumors, considering myelosarcoma as primary manifestation of AML. Intensive AML-specific chemotherapy is generally recommended soon after diagnosis.

Clinical relevance of in vitro chemoresistance in childhood acute myeloid leukemia

To determine the clinical relevance of in vitro drug chemoresistance in childhood acute myeloid leukemia, we used an MTT assay to test leukemic cells from 132 newly diagnosed children. Patients were diagnosed according to the French-American-British (FAB) classification as follows: M0 (n = 12), M1 (n = 16), M2 (n = 53), M4 (n = 17), M5 (n = 19) and M7 (n = 15). The results revealed that, compared to leukemic cells from complete-responders (n = 107), those from non-responders who failed induction therapy (n = 17) were 1.4 to 5.0 times more resistant in vitro to cytarabine (P = 0.005), melphalan (P = 0.003), etoposide (P = 0.011), L-asparaginase (P = 0.017), aclarubicin (P = 0.026) and dexamethasone (P = 0.039). For seven other drugs tested, the median lethal dose of 70% and leukemic cell survival of non-responders were higher than those of complete-responders, but the difference was not statistically significant. We sought correlations between FAB subtypes and in vitro drug resistance. Leukemias of the FAB M4 and M5 subtype were more sensitive to L-asparaginase (P = 0.01, P = 0.0036) than those of the FAB M2 subtype. FAB M5 leukemia was more sensitive to etoposide than were the FAB M2, M4 and M7 subtypes (P = 0.001, P = 0.034, P = 0.023, respectively). By contrast, FAB M5 leukemia was significantly more resistant to prednisolone and dexamethasone than were the FAB M0, M1, M2, M4 and M7 subtypes. We sought correlations between in vitro drug resistance and long-term clinical outcome, but found no associations in this case. These results suggest that in vitro resistance to cytarabine, melphalan, etoposide, L-asparaginase, aclarubicin and dexamethasone might represent factors that can predict response to the early course of therapy. Selecting an appropriate anti-cancer drug according to the FAB classification together with drug sensitivity testing may contribute to improved prognoses in childhood acute myeloid leukemia.

Cerebellar granulocytic sarcoma in an infant with CD56+ acute monoblastic leukemia

Granulocytic sarcoma (GS) is a form of extramedullary leukaemia (EML). The presence of the neural cell adhesion molecule (NCAM) on the surface of the blasts, which is recognized by the CD56 monoclonal antibody, enhances their propensity for tissue penetration. GS within the central nervous system (CNS), in particular within the cerebellum, is extremely uncommon. We review the literature and describe an infant with isolated cerebellar GS relapse, which antedated a CD56+ acute monoblastic leukaemia bone marrow (BM) relapse.