Down's syndrome and acute lymphoblastic leukaemia: clinical features and response to treatment

Advancements in Personalized CAR-T Therapy: Comprehensive Overview of Biomarkers and Therapeutic Targets in Hematological Malignancies

Chimeric antigen receptor T-cell (CAR-T) therapy is a novel anticancer therapy using autologous or allogeneic T-cells. To date, six CAR-T therapies for specific B-cell acute lymphoblastic leukemia (B-ALL), non-Hodgkin lymphomas (NHL), and multiple myeloma (MM) have been approved by the Food and Drug Administration (FDA). Significant barriers to the effectiveness of CAR-T therapy include cytokine release syndrome (CRS), neurotoxicity in the case of Allogeneic Stem Cell Transplantation (Allo-SCT) graft-versus-host-disease (GVHD), antigen escape, modest antitumor activity, restricted trafficking, limited persistence, the immunosuppressive microenvironment, and senescence and exhaustion of CAR-Ts. Furthermore, cancer drug resistance remains a major problem in clinical practice. CAR-T therapy, in combination with checkpoint blockades and bispecific T-cell engagers (BiTEs) or other drugs, appears to be an appealing anticancer strategy. Many of these agents have shown impressive results, combining efficacy with tolerability. Biomarkers like extracellular vesicles (EVs), cell-free DNA (cfDNA), circulating tumor (ctDNA) and miRNAs may play an important role in toxicity, relapse assessment, and efficacy prediction, and can be implicated in clinical applications of CAR-T therapy and in establishing safe and efficacious personalized medicine. However, further research is required to fully comprehend the particular side effects of immunomodulation, to ascertain the best order and combination of this medication with conventional chemotherapy and targeted therapies, and to find reliable predictive biomarkers.

Down syndrome and leukemia: An insight into the disease biology and current treatment options

Children with Down syndrome (DS) have a 10- to 20-fold greater predisposition to develop acute leukemia compared to the general population, with a skew towards myeloid leukemia (ML-DS). While ML-DS is known to be a subtype with good outcome, patients who relapse face a dismal prognosis. Acute lymphocytic leukemia in DS (DS-ALL) is considered to have poor prognosis. The relapse rate is high in DS-ALL compared to their non-DS counterparts. We have a better understanding about the mutational spectrum of DS leukemia. Studies using animal, embryonic stem cell- and induced pluripotent stem cell-based models have shed light on the mechanism by which these mutations contribute to disease initiation and progression. In this review, we list the currently available treatment strategies for DS-leukemias along with their outcome with emphasis on challenges with chemotherapy-related toxicities in children with DS. We focus on the mechanisms of initiation and progression of leukemia in children with DS and highlight the novel molecular targets with greater success in preclinical trials that have the potential to progress to the clinic.

Outcomes in Children, Adolescents, and Young Adults With Down Syndrome and ALL: A Report From the Children's Oncology Group

PURPOSE

Patients with Down syndrome (DS) and B-ALL experience increased rates of relapse, toxicity, and death. We report results for patients with DS B-ALL enrolled on Children's Oncology Group trials between 2003 and 2019.

METHODS

We analyzed data for DS (n = 743) and non-DS (n = 20,067) patients age 1-30 years on four B-ALL standard-risk (SR) and high-risk trials.

RESULTS

Patients with DS exhibited more frequent minimal residual disease (MRD) ≥0.01% at end induction (30.8% v 21.5%; P < .001). This difference persisted at end consolidation only in National Cancer Institute (NCI) high-risk patients (34.0% v 11.7%; P < .0001). Five-year event-free survival (EFS) and overall survival (OS) were significantly poorer for DS versus non-DS patients overall (EFS, 79.2% ± 1.6% v 87.5% ± 0.3%; P < .0001; OS, 86.8% ± 1.4% v 93.6% ± 0.2%; P < .0001), and within NCI SR and high-risk subgroups. Multivariable Cox regression analysis of the DS cohort for risk factors associated with inferior EFS identified age >10 years, white blood count >50 × 103/μL, and end-induction MRD ≥0.01%, but not cytogenetics or CRLF2 overexpression. Patients with DS demonstrated higher 5-year cumulative incidence of relapse (11.5% ± 1.2% v 9.1% ± 0.2%; P = .0008), death in remission (4.9% ± 0.8% v 1.7% ± 0.1%; P < .0001), and induction death (3.4% v 0.8%; P < .0001). Mucositis, infections, and hyperglycemia were significantly more frequent in all patients with DS, while seizures were more frequent in patients with DS on high-risk trials (4.1% v 1.8%; P = .005).

CONCLUSION

Patients with DS-ALL exhibit an increased rate of relapse and particularly of treatment-related mortality. Novel, less-toxic therapeutic strategies are needed to improve outcomes.

Acute onset facial oedema: an unusual presentation of acute lymphoblastic leukaemia in a child

A previously fit and well girl of middle-childhood age presented to her local emergency department after waking with upper-facial swelling. She had a 24-hour preceding history of mild vomiting illness and fatigue. Examination revealed palpable splenomegaly and mild cervical lymphadenopathy, with pitting oedema of the forehead, nasal bridge and eyelids. Admission full blood count showed anaemia and neutropenia, and further investigations confirmed a diagnosis of acute lymphoblastic B-cell leukaemia. X-ray of the chest and CT imaging did not reveal any local facial mass, veno-occlusive disease or mediastinal pathology to explain her facial swelling. She was referred to the tertiary paediatric oncology service for commencement of induction chemotherapy.

Acute Lymphoblastic Leukemia Immunotherapy Treatment: Now, Next, and Beyond

Acute lymphoblastic leukemia (ALL) is a blood cancer that primarily affects children but also adults. It is due to the malignant proliferation of lymphoid precursor cells that invade the bone marrow and can spread to extramedullary sites. ALL is divided into B cell (85%) and T cell lineages (10 to 15%); rare cases are associated with the natural killer (NK) cell lineage (<1%). To date, the survival rate in children with ALL is excellent while in adults continues to be poor. Despite the therapeutic progress, there are subsets of patients that still have high relapse rates after chemotherapy or hematopoietic stem cell transplantation (HSCT) and an unsatisfactory cure rate. Hence, the identification of more effective and safer therapy choices represents a primary issue. In this review, we will discuss novel therapeutic options including bispecific antibodies, antibody-drug conjugates, chimeric antigen receptor (CAR)-based therapies, and other promising treatments for both pediatric and adult patients.

Suspicions regarding the genetic inheritance of acute lymphoblastic leukemia in patients with down syndrome

Children with Down syndrome (DS) are at markedly increased risk for acute lymphoblastic leukaemia (ALL). DS is caused by trisomy of chromosome 21 affecting approximately 1 in 732 newborns in the USA. ALL is the most common cancer in children and constitutes approximately 25% of cancer diagnoses among children under the age of 15. Different protocols for treatment and management of paediatric ALL are available; however, DS children with ALL (DS-ALL) have increased risk of therapy-related toxicity compared to those without DS. Herein, we summarize the available literature on inherited predisposition for ALL, and possibilities for molecular therapy and treatment for DS-ALL patients.

Treatment outcomes in children with Acute lymphoblastic leukemia with versus without coexisting Down's syndrome: A systematic review and meta-analysis

BACKGROUND

Down syndrome (DS) also known as Trisomy 21, is a chromosomal disorder affecting approximately 1 in 732newborns annually in the United States. Children with DS are more likely to develop acute lymphoblastic leukemia (ALL). For the management of pediatric ALL, different treatment protocols have been set up since years. However, ALL children with coexisting DS have shown to have increased therapy-related toxicities compared to those without DS. Therefore, in this study, we aimed to systematically analyze the treatment outcomes in acute ALL children with versus without coexisting DS.

METHODS

Electronic databases including the Web of Science, EMBASE, Cochrane Central, MEDLINE, http://www.ClinicalTrials.gov, and Google scholar were searched for publications reporting treatment related outcomes in ALL children with versus without co-existing DS. Several treatment protocols were used accordingly. This study had a long-term follow-up time period ranging from 5 to 10 years. The RevMan 5.3 software was used to carry out this analysis. Odds ratios (OR) with 95% confidence intervals (CI) were used to represent the results post analysis.

RESULTS

A total number of 31,476 children with ALL enrolled between the years 1981 and 2011 were included. Among the total number of children with ALL, 1303 had coexisting DS. Our results showed that event-free survival was similar in ALL children with versus without DS (odds ratio [OR]: 1.34, 95% confidence interval [CI]: 0.51-3.50; P = .55). Overall mortality (OR: 1.63, 95% CI: 0.86-3.10; P = .13) and participants who achieved clinical remission (OR: 1.04, 95% CI: 0.12-9.29; P = .97) were also similarly manifested. However, treatment-related mortality (OR: 4.29, 95% CI: 2.90-6.36; P = .00001) and induction failure (OR: 2.77, 95% CI: 1.08-7.07; P = .03) were significantly higher in the DS group. Also, total (OR: 1.38, 95% CI: 1.02-1.88; P = .04) and bone marrow relapses (OR: 1.29, 95% CI: 1.00-1.67; P = .05) were significantly higher in ALL children with DS. Nevertheless, central nervous system relapse (OR: 1.15, 95% CI: 0.60-2.20; P = .67), testicular relapse (OR: 0.84, 95% CI: 0.38-1.85; P = .87), and other relapses (OR: 1.12, 95% CI: 0.27-4.62; P = .88) were not significantly different when these outcomes were separately analyzed.

CONCLUSION

Based on this analysis of the treatment outcomes in ALL children with versus without DS, event-free survival, overall mortality, and patients who achieved clinical remission were similar during this long-term follow-up time period. However, due to the significantly higher treatment-related mortality, induction failure, and certain relapses in ALL children with DS, new guidelines might have to focus on reconsidering or modifying treatment regimens for ALL children with DS.

Excellent long-term survival of children with Down syndrome and standard-risk ALL: a report from the Children's Oncology Group

The Children's Cancer Group 1991 study was a clinical trial for children with National Cancer Institute standard-risk acute lymphoblastic leukemia (ALL). This trial demonstrated that 5 doses of vincristine and escalating IV methotrexate (MTX) without leucovorin rescue in the interim maintenance (IM) phases resulted in superior event-free survival (EFS) when compared with 2 doses of vincristine, oral (PO) MTX, PO mercaptopurine, and dexamethasone. This report describes a favorable outcome of this regimen in patients with Down syndrome (DS). Forty-four patients with DS were randomized to the arms containing PO MTX during IM, and 31 to those containing IV MTX. Ten-year EFS rates for patients with DS randomized to IV MTX vs PO MTX were 94.4% ± 5.4% vs 81.5% ± 6.6%, respectively. IV methotrexate with strict escalation parameters, as given in this study, was well tolerated, although the mean total tolerated dose received was lower in patients with DS than in those without DS. There was no increase in hepatic toxicity, systemic infections, or treatment-related deaths in patients with DS during IM on either the IV or PO MTX arms, as compared with those without DS. The incidence of mucositis was increased in patients with DS as compared with patients without DS, particularly among patients who received IV MTX. This trial was registered at www.clinicaltrials.gov as #NCT00005945.

Vemurafenib Treatment of Pleomorphic Xanthoastrocytoma in a Child With Down Syndrome

Brain tumors are the most common solid neoplasms of childhood, but they are very rarely reported in children with Down Syndrome (DS), who develop more commonly different types of malignancies. In particular, we hereby report the case of an 8-years-old child with DS that presented to our attention for neurological and endocrinological issues. Brain imaging revealed the presence of a mass that was partially resected revealing a histological diagnosis of Pleomorphic Xanthoastrocytoma (PXA), a rare WHO grade II tumor extending from the diencephalic region into the surrounding brain tissue. These tumors can harbor the BRAF mutation p.V600E, targetable by the specific inhibitor Vemurafenib. After confirming the presence of the mutation in the tumor, the patient was treated with Vemurafenib. The treatment proved to be effective, leading to a partial response and a stabilization of the disease. Usually, in patients with DS a reduction of the dose of chemotherapeutic drugs is necessary. Vemurafenib was instead well-tolerated as the only observed adverse effect was grade I skin toxicity. This is, to our knowledge, the first case of a PXA reported in a child with DS and the first DS patient treated with Vemurafenib.

Characteristics and survival of children with acute leukemia with Down syndrome or other birth defects in New York State

BACKGROUND

Acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) among DS children have been studied extensively using data from clinical trials or institutional reports. The purpose of this study was to link population-based cancer and birth defects data to evaluate characteristics and survival of children with acute leukemia according to the presence of DS or other birth defects.

METHODS

ALL and AML cases diagnosed between 1983 and 2012 among children aged 0-14 years were obtained from the New York State Cancer Registry. Birth defect status (DS, other birth defects, or no birth defects) was determined by linking with birth defects data. Associations between birth defect status and demographic characteristics were evaluated using contingency table analysis. Ten-year survival was calculated by birth defect status and other potential prognostic factors. Cox proportional hazards regression analysis was also performed.

RESULTS

Among 2941 ALL children, 1.6% had DS, 3.8% had other birth defects, and 94.5% had no birth defects. Birth defect status was significantly associated with age at ALL diagnosis. Survivals were similar among three groups. Among 563 AML children, 11.0% had DS, 6.0% had other birth defects, and 83.0% had no birth defects. Children with DS were more likely to be diagnosed with AML at a younger age and showed the best survival.

CONCLUSION

Age at leukemia diagnosis was significantly associated with the birth defect status. Comparable survival was observed for ALL children. However, AML children with DS demonstrated superior survival compared to children with other birth defects or no birth defects.

Long-term sequelae in survivors of childhood leukemia with Down syndrome: A childhood cancer survivor study report

BACKGROUND

Children with Down syndrome (DS) are at increased risk of developing acute leukemia and are more prone to acute toxicities. We studied the incidence and severity of chronic health conditions among survivors of childhood leukemia with DS compared with those without DS.

METHODS

Chronic health conditions reported by questionnaire were compared between 154 pediatric leukemia survivors with DS and 581 without DS, matched by leukemia, age at diagnosis, race/ethnicity, sex, radiation location and chemotherapy exposure using Cox models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Subjects were selected from 7139 5-year survivors of leukemia in the Childhood Cancer Survivor Study.

RESULTS

Risk of at least 1 late onset chronic health condition (grade 1-5) was similar in the DS population compared with the non-DS group (HR, 1.1; 95% CI, 0.7-1.5). Serious chronic health conditions (grade 3-5) were more common in DS survivors (HR, 1.7; 95% CI, 1.1-2.6), as were ≥ 3 chronic health conditions (grades 1-5) (HR, 1.7; 95% CI, 1.2-2.4). The 25-year cumulative incidence of any condition (grades 1-5) was 83% for DS survivors and 69% for non-DS survivors.

CONCLUSION

Leukemia survivors with DS have therapy-related chronic health conditions comparable to those of similarly treated survivors without DS, with a few notable exceptions: 1) an increased risk of cataracts, hearing loss, and thyroid dysfunction compared with survivors without DS (though these are known risks in the DS population), 2) decreased risk of second cancers, and 3) increased risk of severe or multiple conditions. Practitioners should be aware of these risks during and after therapy. Cancer 2018;124:617-25. © 2017 American Cancer Society.

Acute lymphoblastic leukemia: a comprehensive review and 2017 update

Acute lymphoblastic leukemia (ALL) is the second most common acute leukemia in adults, with an incidence of over 6500 cases per year in the United States alone. The hallmark of ALL is chromosomal abnormalities and genetic alterations involved in differentiation and proliferation of lymphoid precursor cells. In adults, 75% of cases develop from precursors of the B-cell lineage, with the remainder of cases consisting of malignant T-cell precursors. Traditionally, risk stratification has been based on clinical factors such age, white blood cell count and response to chemotherapy; however, the identification of recurrent genetic alterations has helped refine individual prognosis and guide management. Despite advances in management, the backbone of therapy remains multi-agent chemotherapy with vincristine, corticosteroids and an anthracycline with allogeneic stem cell transplantation for eligible candidates. Elderly patients are often unable to tolerate such regimens and carry a particularly poor prognosis. Here, we review the major recent advances in the treatment of ALL.

Supportive care utilization and treatment toxicity in children with Down syndrome and acute lymphoid leukaemia at free-standing paediatric hospitals in the United States

Although inferior outcomes of children with Down syndrome (DS) and acute lymphoid leukaemia (ALL) are established, national supportive care patterns for these patients are unknown. A validated retrospective cohort of paediatric patients diagnosed with ALL from 1999 to 2011 was assembled from the US Pediatric Health Information System (PHIS) database to examine organ toxicity, sepsis, and resource utilization in children with and without DS. Among 10699 ALL patients, 298 had DS-ALL (2·8%). In a multivariate model, DS was associated with increased risk of cardiovascular (odds ratio [OR] 2·0, 95% confidence interval [CI] 1·6-2·7), respiratory (OR 2·1, 95% CI: 1·6-2·9), neurologic (OR 3·4, 95% CI 1·9-6·2), and hepatic (OR 1·4, 95% CI 1·0-1·9) dysfunction and sepsis (OR 1·8, 95% CI: 1·4-2·4). Children with DS-ALL used significantly more respiratory support, insulin, and anti-infectives, including broad-spectrum Gram-positive agents, quinolones, and azoles. They used significantly fewer analgesics and antiemetics compared to non-DS-ALL children. Ultimately, this study confirms the increased risk of infectious and end-organ toxicity in children with DS-ALL and quantifies important differences in resource utilization between children with DS and non-DS ALL. These findings highlight the importance of investigating the impact of these care variations and developing specific supportive care guidelines for this population.

B-acute lymphoblastic leukemia/lymphoblastic lymphoma

OBJECTIVES

This session of the 2013 Society of Hematopathology/European Association for Haematopathology Workshop was dedicated to B-acute lymphoblastic leukemia (B-ALL)/lymphoblastic lymphoma (LBL) with recurrent translocations and not otherwise specified.

METHODS

In this review, we summarize the cases discussed during the workshop, review the pertinent and most recent literature on the respective topics, and provide a few key points that may aid in the workup of patients with B-ALL/LBL.

RESULTS

Many of the submitted cases showed interesting diagnostic, immunophenotypic, or clinical aspects of B-ALL with BCR/ABL1, MLL-associated, and other recurrent chromosomal abnormalities. Several cases showed rare aberrancies such as coexistent IGH/BCL2 and MYC rearrangements and raised issues in classification. Other cases had unusual clinical presentations, including B-ALL with hypereosinophilia and therapy-related B-ALL. Several cases highlighted the role of flow cytometry immunophenotyping in distinguishing benign B-cell precursors from aberrant lymphoblasts, and other cases raised questions regarding the clinical importance of myeloperoxidase positivity in acute lymphoblastic leukemia.

CONCLUSIONS

The complexity and spectrum of cases presented in this review highlight the importance of clinicopathologic correlation and the value of ancillary studies in the classification and workup of patients with B-ALL/LBL.

Down syndrome preleukemia and leukemia

Children with Down syndrome (DS) and acute leukemias acute have unique biological, cytogenetic, and intrinsic factors that affect their treatment and outcome. Myeloid leukemia of Down syndrome (ML-DS) is associated with high event-free survival (EFS) rates and frequently preceded by a preleukemia condition, the transient abnormal hematopoiesis (TAM) present at birth. For acute lymphoblastic leukemia (ALL), their EFS and overall survival are poorer than non-DS ALL, it is important to enroll them on therapeutic trials, including relapse trials; investigate new agents that could potentially improve their leukemia-free survival; and strive to maximize the supportive care these patients need.

Child and adolescent Down syndrome-associated leukaemia: the Irish experience

BACKGROUND

Down syndrome (DS), the most common syndromic chromosomal abnormality is associated with a unique susceptibility to develop both acute myeloid (ML) and lymphoblastic leukaemia (ALL). These leukaemias differ from the non-DS-related types of leukaemia and are thought to be distinct biological entities.

AIMS

To perform a retrospective review of our experience of treating DS-related leukaemia at Our Lady's Children's Hospital.

METHODS

Data were extracted from a database established in 2000 to prospectively gather data on DS-associated leukaemias and their outcomes following polychemotherapy. Kaplan-Meier survival curves were constructed.

RESULTS

Nineteen patients with DS-ML were treated and 19 with DS-ALL. Sixteen (84%) patients with DS-ML are alive and in complete remission with a median follow-up of 7 years. All deaths in this cohort were due to treatment-related mortality (TRM). Of the DS-ALL patients, 12 (63%) remain alive with a median follow-up of 3.6 years. TRM accounted for five of the six deaths. One death was due to leukaemic relapse.

CONCLUSION

High cure rates are seen in DS-ML using contemporary polychemotherapy protocols, however, there is significant TRM in this cohort. DS-ALL does not have the same high cure rate as non-DS-ALL (>90%) and again this is mainly due to an excess of TRM.

Clinical and genetic features of pediatric acute lymphoblastic leukemia in Down syndrome in the Nordic countries

Background

Children with Down syndrome (DS) have an increased risk for acute lymphoblastic leukemia (ALL). Although previous studies have shown that DS-ALL differs clinically and genetically from non-DS-ALL, much remains to be elucidated as regards genetic and prognostic factors in DS-ALL.

Methods

To address clinical and genetic differences between DS-ALL and non-DS-ALL and to identify prognostic factors in DS-ALL, we ascertained and reviewed all 128 pediatric DS-ALL diagnosed in the Nordic countries between 1981 and 2010. Their clinical and genetic features were compared with those of the 4,647 B-cell precursor (BCP) ALL cases diagnosed during the same time period.

Results

All 128 DS-ALL were BCP ALL, comprising 2.7% of all such cases. The 5-year event-free survival (EFS) and overall survival (OS) were significantly (P = 0.026 and P = 0.003, respectively) worse for DS-ALL patients with white blood cell counts ≥50 × 10⁹/l. The age distributions varied between the DS and non-DS cases, with age peaks at 2 and 3 years, respectively; none of the DS patients had infant ALL (P = 0.029). The platelet counts were lower in the DS-ALL group (P = 0.005). Abnormal karyotypes were more common in non-DS-ALL (P < 0.0001), and there was a significant difference in the modal number distribution, with only 2% high hyperdiploid DS-ALL cases (P < 0.0001). The 5-year EFS and 5-year OS were significantly worse for DS-ALL (0.574 and 0.691, respectively) compared with non-DS-ALL (0.783 and 0.894, respectively) in the NOPHO ALL-1992/2000 protocols (P < 0.001).

Conclusions

The present study adds further support for genetic and clinical differences between DS-ALL and non-DS-ALL.

Outcome of Down syndrome associated acute lymphoblastic leukaemia treated on a contemporary protocol

We report the outcome for children and young people with Down syndrome-associated acute lymphoblastic leukaemia (DS-ALL) treated on a contemporary protocol. Compared with non-DS ALL, patients with DS-ALL had an inferior event-free survival (65·6% vs. 87·7% at 5 years; P < 0·00005) and overall survival (70·0% vs. 92·2%; P < 0·00005). Excess treatment-related mortality - was primarily responsible for the worse outcomes for DS-ALL (21·6% at 5 years, vs. 3·3%, P < 0·00005). Minimal residual disease (MRD) risk status was highly discriminant for relapse in DS patients with 0/28 relapses in the MRD low risk group.

How I treat ALL in Down's syndrome: pathobiology and management

Children with Down syndrome are at high risk for developing B-cell precursor acute lymphoblastic leukemia (DS-ALL) associated with poor outcome due to both a high relapse rate and increased treatment-related mortality (TRM) from infections. Biologically, these heterogeneous leukemias are characterized by under-representation of the common cytogenetic subgroups of childhood ALL and overrepresentation of CRLF2-IL7R-JAK-STAT activating genetic aberrations. Although relapse is the major determinant of poor outcomes in this population, de-escalation of chemotherapy intensity might be feasible in the 10% to 15% DS-ALL patients with ETV6-RUNX1 or high hyperdipoidy in whom TRM is the major limiting event. As infection-associated TRM occurs during all treatment phases, including the maintenance period, increased surveillance and supportive care is required throughout therapy. Improvement in outcome will require better understanding of the causes of treatment failure and TRM, incorporation of new therapies targeting the unique biological properties of DS-ALL, and enhanced supportive care measures to reduce the risk of infection-related TRM. To facilitate these goals, an international collaboration plans to establish a prospective DS-ALL registry and develop specific supportive care recommendations for this at-risk population.

Physicians compliance during maintenance therapy in children with Down syndrome and acute lymphoblastic leukemia

Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) have an inferior prognosis compared with non-DS ALL patients. We reviewed methotrexate (MTX)/mercaptopurine (6MP) maintenance therapy data for children with DS treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL92 or the NOPHO ALL2000 protocols between 1992 and 2007. The 5-year event-free survival probability (pEFS(5 yr)) for the 66 DS patients was inferior to the 2602 non-DS patients (0.50 ± 0.07 vs 0.77 ± 0.01 (P<0.001)). The 48 DS patients in first remission at the beginning of maintenance therapy had pEFS(10 yr) below that of the 522 non-DS control patients (pEFS(10 yr): 0.58 (95% confidence interval (CI) 0.43-0.77) vs 0.83 (95% CI 0.80-0.86), respectively (P<0.0001)). The DS patients received lower median doses of MTX (median: 11.8 vs 15.4 (P<0.0001)) and 6MP (median: 43.6 vs 59.4 (P<0.0001)). In Cox regression analysis, male gender, presence of DS and high median maintenance therapy white blood cell levels (mWBC) were associated with increased risk for relapse. DS-ALL patients with mWBC above or below 3.5 × 10(9)/l (protocol target) had pEFS(10 yr) of 0.31 and 0.72 (P=0.02), and the mWBC hazard ratio for DS-ALL patients was 2.0 (P<0.0005). We conclude that insufficient treatment intensity during maintenance therapy of DS-ALL patients may contribute to their poor prognosis.

[Trisomy 21 and cancers]

Patients with trisomy 21, still called Down's syndrome (DS), present a particular tumoral profile compared to the general population with an increased incidence of leukaemia in the childhood and a low risk of solid cancer in the adulthood. DS children indeed present a 50-fold risk of developing a leukaemia compared to age-matched non-trisomic children and most of them develop a specific myelodysplasic disorder called transient myelodysplasic disorder. In spite of the low incidence of solid tumors, some are very rare as breast cancer, nephroblastoma, neuroblastoma and medulloblastoma, whereas the others remain more frequent as retinoblastoma, lymphoma and gonadal and extragonadal germ cell tumours. In this review, we present possible mechanisms which can favour, or on the contrary repress the formation and progression of tumours in DS patients, which are related to gene effect dosage of oncogenes or tumour repressors on chromosome 21, tumour angiogenesis, apoptosis and epithelial cell-stroma interactions.

Tumorigenesis in Down's syndrome: big lessons from a small chromosome

If assessed by a number of criteria for cancer predisposition, Down's syndrome (DS) should be an overwhelmingly cancer-prone condition. Although childhood leukaemias occur more frequently in DS, paradoxically, individuals with DS have a markedly lower incidence of most solid tumours. Understanding the mechanisms that are capable of overcoming such odds could potentially open new routes for cancer prevention and therapy. In this Opinion article, we discuss recent reports that suggest unique and only partially understood mechanisms behind this paradox, including tumour repression, anti-angiogenic effects and stem cell ageing and availability.

Acute leukemias in children with Down syndrome

Children with Down syndrome (DS) often present with hematopoietic abnormalities, and are at increased risk of developing leukemia. Specifically, 3-10% of newborns with DS are diagnosed with transient myeloproliferative disease, and children with DS are 500 times more likely to develop acute megakaryoblastic leukemia (AMKL) and 20 times more likely to develop acute lymphoblastic leukemia (ALL) than typical children. This review examines the characteristics of these leukemias and their development in the unique genetic background of trisomy 21. A discussion is also provided for areas of future research and potential therapeutic development.

Outcome in children with Down's syndrome and acute lymphoblastic leukemia: role of IKZF1 deletions and CRLF2 aberrations

Children with Down's syndrome (DS) have an increased risk of developing acute lymphoblastic leukemia (ALL) and have a low frequency of established genetic aberrations. We aimed to determine which genetic abnormalities are involved in DS ALL. We studied the frequency and prognostic value of deletions in B-cell development genes and aberrations of janus kinase 2 (JAK2) and cytokine receptor-like factor 2 (CRLF2) using array-comparative genomic hybridization, and multiplex ligation-dependent probe amplification in a population-based cohort of 34 Dutch Childhood Oncology Group DS ALL samples. A population-based cohort of 88 DS samples from the UK trials was used to validate survival estimates for IKZF1 and CRLF2 abnormalities. In total, 50% of DS ALL patients had ≥1 deletion in the B-cell development genes: PAX5 (12%), VPREB1 (18%) and IKZF1 (35%). JAK2 was mutated in 15% of patients, genomic CRLF2 rearrangements in 62%. Outcome was significantly worse in patients with IKZF1 deletions (6-year event-free survival (EFS) 45 ± 16% vs 95 ± 4%; P=0.002), which was confirmed in the validation cohort (6-year EFS 21 ± 12% vs 58 ± 11%; P=0.002). This IKZF1 deletion was a strong independent predictor for outcome (hazard ratio EFS 3.05; P=0.001). Neither CRLF2 nor JAK2 were predictors for worse prognosis. If confirmed in prospective series, IKZF1 deletions may be used for risk-group stratification in DS ALL.

Myeloid leukaemia in children with Down syndrome: report of the registry-based French experience between 1990 and 2003

AIM

To determine the epidemiology of myeloid leukaemia (ML) in children with Down syndrome (DS) and the efficacy of two approaches, low-dose cytarabine-based regimen (LDC) and standard-dose intensive chemotherapy (SD).

PROCEDURE

All children with Down syndrome aged from 2 months to 15 years with ML/myelodysplasia registered in the French registry between January 1990 and December 2003 were included.

RESULTS

Forty-four patients were included. The median age was 1.75 years. The French-America-British subtypes were as follows: M7: 24, M0: 6, M2: 5, M6: 2. Forty-three patients were treated with curative prospect, 20 patients with LDC regimen and 22 according to SD protocols, 1 was given the LDC regimen plus autologous stem-cell transplantation. The event-free survival (EFS) and overall survival (OS) at 5 years were 64.4% and 76.8%. At 5 years, OS in LDC and SD groups were 65% and 85.9% (P = 0.08). EFS were 45% and 80.3% respectively (P < 0.01).

CONCLUSION

Children with DS can adequately tolerate SD chemotherapy with a significant superiority of EFS relative to LDC. We suggest that higher levels of cure can be obtained in DS-ML with SD chemotherapy including cytarabine and anthracyclines.

Down syndrome childhood acute lymphoblastic leukemia has a unique spectrum of sentinel cytogenetic lesions that influences treatment outcome: a report from the Children's Oncology Group

Children with Down syndrome (DS) have an increased risk of acute lymphoblastic leukemia (ALL) and an inferior outcome. We reviewed data from 2811 children with ALL enrolled in Children's Oncology Group P9900, which included prospective testing for the major cytogenetic lesions in childhood ALL: ETV6-RUNX1, TCF3-PBX1, BCR-ABL1, and MLL translocations and trisomies of chromosomes 4 and 10. Eighty (3%) B-precursor ALL patients had DS. Age, sex, white blood cell count, and risk group were similar between DS-ALL and non-DS-ALL but significantly more patients with DS-ALL were white (91.2% vs 76.4%, P = .001). Children with DS-ALL had lower rates of the favorable cytogenetic lesions ETV6-RUNX1 (2.5% vs 24%, P < .001) and trisomies 4 and 10 (7.7% vs 24%, P < .001). Five-year event-free (EFS) and overall survival (OS) were inferior in children with DS-ALL: 69.9% +/- 8.6% versus 78.1% +/- 1.2% (P = .078), and 85.8% +/- 6.5% versus 90.0% +/- 0.9% (P = .033). However, when children with MLL translocations, BCR-ABL1, ETV6-RUNX1, and trisomies 4 and 10 were excluded, the EFS and OS were similar for children with and without DS (EFS 68.0 %+/- 9.3% vs 70.5% +/- 1.9%, P = .817; and OS 86.7% +/- 6.7% vs 85.4% +/- 1.5%; P = .852), both overall and adjusted for race. DS-ALL displays a unique spectrum of biologic subtypes with different frequencies of sentinel cytogenetic lesions having a large influence on outcome.

Methotrexate-induced side effects are not due to differences in pharmacokinetics in children with Down syndrome and acute lymphoblastic leukemia

BACKGROUND

Children with Down syndrome have an increased risk of developing acute lymphoblastic leukemia and a poor tolerance of methotrexate. This latter problem is assumed to be caused by a higher cellular sensitivity of tissues in children with Down syndrome. However, whether differences in pharmacokinetics play a role is unknown.

DESIGN AND METHODS

We compared methotrexate-induced toxicity and pharmacokinetics in a retrospective case-control study between patients with acute lymphoblastic leukemia who did or did not have Down syndrome. Population pharmacokinetic models were fitted to data from all individuals simultaneously, using non-linear mixed effect modeling.

RESULTS

Overall, 468 courses of methotrexate (1-5 g/m(2)) were given to 44 acute lymphoblastic leukemia patients with Down syndrome and to 87 acute lymphoblastic leukemia patients without Down syndrome. Grade 3-4 gastrointestinal toxicity was significantly more frequent in the children with Down syndrome than in those without (25.5% versus 3.9%; P=0.001). The occurrence of grade 3-4 gastrointestinal toxicity was not related to plasma methotrexate area under the curve. Methotrexate clearance was 5% lower in the acute lymphoblastic leukemia patients with Down syndrome (P=0.001); however, this small difference is probably clinically not relevant, because no significant differences in methotrexate plasma levels were detected at 24 and 48 hours.

CONCLUSIONS

We did not find evidence of differences in the pharmacokinetics of methotrexate between patients with and without Down syndrome which could explain the higher frequency of gastrointestinal toxicity and the greater need for methotrexate dose reductions in patients with Down syndrome. Hence, these problems are most likely explained by differential pharmaco-dynamic effects in the tissues between children with and without Down syndrome. Although the number of patients was limited to draw conclusions, we feel that it may be safe in children with Down syndrome to start with intermediate dosages of methotrexate (1-3 g/m(2)) and monitor the patients carefully.

A comparison of acute lymphoblastic leukemia in Down syndrome and non-Down syndrome children: the role of trisomy 21

Down syndrome (DS), which occurs once in every 800 births, is associated with a trisomy on locus 21. Among the many aberrations caused by DS, including shortened stature and distorted facies, are several blood dyscrasias, including childhood leukemias-namely, acute myeloid leukemia (AML) and acute lymphoblastic, or lymphocytic, leukemia (ALL). One focus of the diagnosis of ALL is to distinguish it from AML.The benefits of immunophenotyping extend to treatment as well. ALL is associated with an inherited trisomy 21 in DS children (ALL-DS) and with acquired trisomies, +21, 8, and 13, in non-DS children (ALL-NDS). The differences in treatment, outcome, and prognosis between ALL-DS and ALL-NDS can be attributed to the interaction of their respective trisomies with several genetic mutations, including one on the GATA1 growth factor transcription gene. Other mutations are the gene fusion at TEL/AML1, and a new mutation found, which labels the Janus Kinase gene or JAK2 as on oncogenic precursor, which when associated with the B-cell precursor gene or BCP is highly leukomogenic. The treatments for the 2 groups have been based on quality of risk, with ALL-DS children having the highest risk along with the poorest prognosis, but alterations in medication regimens have brought treatment outcomes to near equality. It is worthwhile to study the trisomy 21 because in the future it may provide an understanding of all blood dyscrasias.

Insights into the manifestations, outcomes, and mechanisms of leukemogenesis in Down syndrome

Children with Down syndrome (DS) show a spectrum of clinical anomalies, including cognitive impairment, cardiac malformations, and craniofacial dysmorphy. Moreover, hematologists have also noted that these children commonly show macrocytosis, abnormal platelet counts, and an increased incidence of transient myeloproliferative disease (TMD), acute megakaryocytic leukemia (AMKL), and acute lymphoid leukemia (ALL). In this review, we summarize the clinical manifestations and characteristics of these leukemias, provide an update on therapeutic strategies and patient outcomes, and discuss the most recent advances in DS-leukemia research. With the increased knowledge of the way in which trisomy 21 affects hematopoiesis and the specific genetic mutations that are found in DS-associated leukemias, we are well on our way toward designing improved strategies for treating both myeloid and lymphoid malignancies in this high-risk population.

Malignancy in children with trisomy 21

Patients with Down syndrome (DS) display a unique spectrum of malignancies, with a 10- to 20-fold higher risk of acute leukemias, and a markedly lower incidence of solid tumors. This review discusses the current understanding of the basis for this distinctive pattern of cancer incidence and the clinical and biologic features of the malignant disorders most frequent in DS individuals: transient myeloproliferative disease, acute megakaryoblastic leukemia, and acute lymphoblastic leukemia. We also review distinctive pharmacogenetic issues, highlighting the differential chemosensitivity and toxicity profiles of DS patients compared with the general population, and epidemiologic studies of protective and adverse environmental risk factors for the development of leukemia.

Vincristine pharmacokinetics in children with Down syndrome

Children with Down syndrome (DS), who represent about 2% of childhood acute lymphoblastic leukemia, have inferior prognosis compared to non-DS children. For vincristine (and many other anticancer agents) pharmacokinetic data are scant or missing, and there is considerable uncertainty about the optimal dosing of drugs to patients with DS. We studied vincristine pharmacokinetics on treatment day one in six children with DS and compared to 92 non-DS children. No differences were found. Thus, we found no rationale for dose reduction of vincristine in DS children from a strictly pharmacokinetic point of view.

Outcome and toxicity of chemotherapy for acute lymphoblastic leukemia in children with Down syndrome

BACKGROUND

Acute lymphoblastic leukemia (ALL) in children with Down syndrome (DS) presents with an increased incidence, higher frequency of adverse effects and inferior probability of survival. Attempts at improving outcomes face the dilemma posed by the need to avoid excessive toxicity while maintaining the efficacy of treatment. Dose reductions and avoidance of infusions of intermediate and high-dose methotrexate are common in this group.

PROCEDURE

In a matched pair analysis we compared adverse effects and survival after ALL chemotherapy using intermediate and high doses of methotrexate in children with and without Down syndrome.

RESULTS

Following intermediate and high doses of methotrexate to treat primary ALL, children with DS did not require opiate analgesia and parenteral nutrition for severe mucositis more often than children without DS. Children with DS spent more days in hospital and missed more doses of maintenance chemotherapy. Chemotherapy dose reductions were common and in this study had no detectable adverse impact. Event-free and overall survival (OS) of children with ALL was lower in the DS than the non-Down syndrome (NDS) control group. The difference, however, was no longer significant during the recent treatment era.

CONCLUSIONS

The feasibility of all treatment elements that are efficacious in pediatric ALL needs to be carefully considered in children with DS. In addition to survival data, the prospective collection of data on both adverse events and treatment modifications is essential to strike a balance between the avoidance of adverse effects and the need for intensive therapy that will safely improve ALL outcomes in this group.

Acute lymphoblastic leukemia and Down syndrome: presenting features and treatment outcome in the experience of the Italian Association of Pediatric Hematology and Oncology (AIEOP)

BACKGROUND

The presenting features and treatment outcome of 120 patients with Down syndrome (DS) and childhood acute lymphoblastic leukemia (ALL) were compared with 6237 non-DS patients treated in the same years.

METHODS

We reviewed the database of 6 consecutive Italian Association of Pediatric Hematology and Oncology (AIEOP)-ALL trials conducted between 1982 and 2004. Features of DS patients were compared with those of non-DS patients.

RESULTS

The 120 DS patients (1.9%) were more often girls (P = .027), aged > or = 10 years (P = .014), and high risk according to National Cancer Institute (NCI) criteria (P = .045). The distribution of white blood cell count did not differ (P = .32). DS patients belonged less frequently to the current high-risk group (P = .017). In all but 1 case they demonstrated B-cell precursor (BCP) immunophenotype (P < or = .001). TEL/AML1 molecular fusion transcript was found in only 1 of 44 (2.2%) tested patients. Induction death occurred more often in DS patients (4.2%, P = .009), but not failure to achieve remission. Leukemia relapse occurred in 31.6% of DS patients (vs 23.5%; P = .003), usually in the marrow. Remission death was more frequent in DS patients (4.2%, P = .03). Ten-year event-free survival and survival were significantly worse compared with non-DS patients (P < 0.001). DS patients diagnosed since 1995 had a better outcome (P = .06) than those diagnosed in previous years, but still had worse outcomes than non-DS patients (P = .04). Event-free survival of DS patients at NCI standard risk was lower than that of non-DS patients (P = .006).

CONCLUSIONS

Presenting features of childhood ALL in DS differ from those in non-DS patients. They are almost invariably characterized by BCP phenotype, and are often TEL/AML1 negative. Treatment results, although not as good as for non-DS patients, improved progressively, with modern therapy and support allowing 75% to survive.

Cytogenetic features of acute lymphoblastic and myeloid leukemias in pediatric patients with Down syndrome: an iBFM-SG study

Children with Down syndrome (DS) have a markedly increased risk of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). To identify chromosomal changes cooperating with +21 that may provide information on the pathogenesis of these leukemias, we analyzed 215 DS-ALLs and 189 DS-AMLs. Unlike previous smaller series, a significant proportion of DS-ALLs had the typical B-cell precursor ALL abnormalities high hyperdiploidy (HeH; 11%) and t(12;21)(p13;q22) (10%). The HeH DS-ALLs were characterized by gains of the same chromosomes as non–DS-HeH, suggesting the same etiology/pathogenesis. In addition, specific genetic subtypes of DS-ALL were suggested by the significant overrepresentation of cases with +X, t(8;14)(q11;q32), and del(9p). Unlike DS-ALL, the common translocations associated with non–DS-AML were rare in DS-AML, which instead were characterized by the frequent presence of dup(1q), del(6q), del(7p), dup(7q), +8, +11, del(16q), and +21. This series of DS leukemias—the largest to date—reveals that DS-ALL is a heterogeneous disorder that comprises both t(12;21) and HeH as well as DS-related abnormalities. Furthermore, this analysis confirms that DS-AML is a distinct entity, originating through other genetic pathways than do non–DS-AMLs, and suggests that unbalanced changes such as dup(1q), +8, and +21 are involved in the leukemogenic process.

Hospitalizations of infants and young children with Down syndrome: evidence from inpatient person-records from a statewide administrative database

BACKGROUND

Although individuals with Down syndrome are increasingly living into the adult years, infants and young children with the syndrome continue to be at increased risk for health problems. Using linked, statewide administrative hospital discharge records of all infants with Down syndrome born over a 3-year period, this study 'follows forward' over 200 infants with Down syndrome from each individual's birth until they turn 3 years of age. By utilizing this procedure, we were able to assess the amount, reasons for, and timing of inpatient hospitalization and to investigate how congenital heart defects (CHDs) relate to hospitalization for young children with Down syndrome.

METHOD

This population-based, retrospective study used statewide administrative hospital discharge data. Subject inclusion criteria included residents of Tennessee, born between 1997 and 1999, and diagnosed with Down syndrome at birth. Inpatient records were linked to create person-record histories of hospitalization from birth to age 3. Main outcomes included the number of Non-birth Hospitalizations, length of stay, principal and other diagnosis codes to indicate reason(s) for hospitalization, and patient's age at first (non-birth) hospitalization. Procedure codes were added to determine if children with CHD were hospitalized primarily for operations on the heart.

RESULTS

Of 217 births, 213 children survived birth; 54% (115) had CHDs. Almost half (49.8%) of all children were hospitalized before age 3; these 106 children were admitted 245 times. Children with CHDs were 2.31 times more likely to be hospitalized than children without CHDs. Respiratory illnesses affected 64.9% of all hospitalized children with CHD, were the principal diagnoses in 38.3% of their hospitalizations, and were the main principal diagnoses for non-CHD children. Thirty-three (of 77) hospitalized children with CHD underwent cardiac surgeries, accounting for 19.3% of all admissions. Median time to first hospitalization was 96 days (CI: 78-114) for CHD infants, 197 days (CI: 46-347) for non-CHD infants.

CONCLUSIONS

Children with Down syndrome are at high risk for early hospitalization. Prevention and treatment of respiratory illnesses require more attention. Down syndrome is associated with early, serious, physical health problems and substantial inpatient care use.

Haematology of Down syndrome

Down syndrome is a common congenital disorder affecting approximately 1/1000 live births. Newborns and children with Down syndrome may present with many haematological problems. In addition, benign abnormalities of the blood count and blood film, which may manifest at any age, population-based and cancer-based registries and clinical trials suggest there is a approximately 12-fold increased risk of acute lymphoblastic leukaemia in the age group of 5-30 years that rises to approximately 40-fold in children younger than 5 years, and that there is a approximately 150-fold increased risk of acute myeloid leukaemia in children younger than 5 years. There is also a virtually unique predisposition to a transient neonatal leukaemia, known as transient abnormal myelopoiesis. Deaths from leukaemia, in part, account for the excess mortality associated with Down syndrome. This article reviews the clinical presentation and the progress made in the management of these disorders over the past decade. It also briefly considers the recent exciting scientific advances that have potential to transform management of leukaemia in children with Down syndrome and also have implications for management of childhood leukaemia more generally.

Evaluation of residual tissues after adjuvant therapy in germ cell tumors

OBJECTIVE

Germ cell tumors are the tumors sensitive for adjuvant therapy such as radiotherapy and chemotherapy. We evaluated the pathological findings of these heterogeneous tumors to determine the persistence of residual viable tumor cells after adjuvant therapy.

PATIENTS AND METHODS

Between 1988 and 2005, we treated 31 patients with germinoma or germinoma with syncytiotrophoblastic giant cells (STGC) and 15 patients with non-germinomatous malignant germ cell tumors (NGMGCTs). All 46 patients received a combination of chemo- and radiotherapy. A second-look operation was performed in 3 of 31 patients with germinomas or germinomas with STGC and 12 of 15 patients with NGMGCTs. The follow-up period was 2-139 months (median 95) in patients with germinomas or germinomas with STGC (group 1) and 10-202 months (median 65) in NGMGCT patients (group 2).

RESULTS

Post-treatment, 3 group 1 and 12 group 2 patients manifested residual tumors. The pathological diagnosis in group 1 patients was mature teratoma, pineal cyst, and fibrous tissue with calcification; in group 2 it was yolk sac tumor (n = 1), immature teratoma (n = 3), mature teratoma (n = 4), and necrosis or fibrous tissue (n = 4). While no group 1 patients manifested tumor cells, MIB-1-positive viable tumor cells were present in resected tissues from one-third of the group 2 patients (3 immature teratomas and 1 yolk sac tumor).

CONCLUSION

The absence of viable tumor cells in residual tissue indicates that the combination of cisplatin-based chemo- and radiotherapy was effective in our germinoma patients. On the other hand, in patients with NGMGCTs, these cells persisted despite this combination therapy.

Down syndrome and acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia in children with Down syndrome (ALL-DS) is characterised by unique clinical and biological features. Notable among these are an absence of ALL in DS patients <1 year of age; a lower incidence of favourable and unfavourable chromosomal translocations; heightened sensitivity to methotrexate; and an increased propensity to infections. Although children with ALL-DS have historically fared less well than their non-DS counterparts (ALL-NDS), recent data indicate that outcomes in ALL-DS are now comparable with ALL-NDS with risk-adapted therapies, after adjusting for biological differences between the ALL-DS and ALL-NDS populations. Given the increased risk of ALL-DS patients for treatment-related toxicities, further intensification of therapy may not yield continued improvements in survival. Future investigations in the ALL-DS population should focus on maintaining excellent outcomes while reducing treatment-related complications through novel treatment strategies, such as the integration of targeted noncytotoxic agents.

Down syndrome with low hypodiploidy in precursor B-cell acute lymphoblastic leukemia

We describe the rare finding of a 33-month-old child neonatally diagnosed with Down syndrome, who presented with pre-B acute lymphoblastic leukemia (ALL) with a pretreatment bone marrow karyotype in which a low hypodiploid cell line (38 chromosomes) was identified in 17/19 cells studied. The abnormal cell line retained the extra constitutional chromosome 21. Hypodiploidy (loss of one or more chromosomes) is seen in approximately 5% of all childhood pre-B ALL cases and in approximately 2.2% cases of individuals with a constitutional trisomy 21. Low hypodiploidy, associated with a high risk of relapse, is rare in pediatric ALL cases in the general population, and, to our knowledge, is previously unreported in patients with trisomy 21.

Adult acute lymphoblastic leukemia

Much progress has been made in understanding the biology of and therapy for acute lymphoblastic leukemia (ALL). This progress has translated into the recognition of several subgroups of ALL and the institution of risk-adapted therapies. New therapies are emerging based on the definition of specific cytogenetic-molecular abnormalities. Changes in the pathologic classification of ALL have led to therapeutic consequences. Adaptation of successful treatment strategies in children with ALL has resulted in similar complete remission rates in adults. Prognosis has Improved especially in mature B-cell ALL and T-cell lineage ALL. However, regardless of ALL subgroup, long-term survival in adults is still inferior to that in children. Development of new drugs and agents tailored to subset-specific cytogenetic-molecular characteristics is vital to the therapeutic success in adult ALL.

Equal frequency of TEL/AML1 rearrangements in children with acute lymphoblastic leukemia with and without Down syndrome

Constitutional trisomy 21 is the most prominent predisposing factor to childhood leukemia, whereas the t(12;21)(p13;q22) with its molecular genetic counterpart, the TEL/AML1 fusion gene, is the most common acquired chromosomal rearrangement in childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1+ BCP ALL is extremely low in patients with Down syndrome (DS). To further investigate this issue in a population-based fashion, the authors retrospectively assessed the number of DS patients with a TEL/AML1+ ALL in two consecutive Austrian ALL multicenter trials. Accordingly, they were able to analyze 8 of 10 individuals with DS and a BCP ALL, two of whom who suffered from a TEL/AML1+ leukemia. Based on this observation they concluded that individuals with BCP leukemia and a constitutional trisomy 21 may have similar likelihood to have a TEL/AML1 rearrangement as BCP ALL patients without this specific predisposing factor.

Acute leukaemia in children with Down syndrome: a population-based Nordic study

To determine the epidemiology and outcome of children with Down syndrome (DS) diagnosed with acute leukaemia in the Nordic countries, data registered in the Nordic Society of Paediatric Haematology and Oncology (NOPHO) population-based leukaemia registry were analysed. Of 3494 children with acute leukaemia diagnosed between July 1984 and December 2001, 136 patients (3.9%) with DS were identified. 2.1% of the children with acute lymphoid leukaemia (ALL) and 14.0% of the children with acute myeloid leukaemia (AML) had DS. In ALL, DS patients had similar age and sex distribution and no major differences in blood counts compared with non-DS children. None of the DS patients had T cell leukaemia. Outcome was inferior to that of non-DS children and treatment results did not improve over time. In AML, DS patients showed a significant female predominance and all but one were <5 years old. DS patients with AML had significantly lower platelet and white blood cell counts and two-thirds were type M7 as according to the French-American-British classification. None of the patients <5 years of age had typical AML cytogenetic aberrations. Outcome was far better in the DS group. DS patients treated for AML after 1992 had an excellent outcome (probability of event-free survival, 83 +/- 6%). The high proportion of female DS patients with AML is unexplained. The differing treatment results in AML versus ALL need further evaluation and represent a challenge for the coming years.

Lymphoblast biology and outcome among children with Down syndrome and ALL treated on CCG-1952

BACKGROUND

Patients with Down syndrome (DS) and standard risk (SR) acute lymphoblastic leukemia (ALL-DS) are reported to have inferior event free (EFS) and overall survival (OS) compared to patients without DS (ALL-NDS).

PROCEDURE

We compared the prevalence of favorable and unfavorable clinical and biologic features, toxicity and outcome within the ALL-DS and ALL-NDS cohorts of 2,174 eligible patients with SR-ALL enrolled on CCG-1952.

RESULTS

Fifty-nine patients (3%) had ALL-DS. DS patients were less likely to have either favorable (hyperdiploidy, triple trisomy of chromosomes 4, 10, and 17, TEL-AML1 rearrangement) or unfavorable (T-cell ALL, hypodiploidy, adverse translocations) biologic features. Toxicity occurred significantly more often and number of days hospitalized was significantly greater in ALL-DS than in ALL-NDS. ALL-DS patients had an inferior 4-year EFS compared to the NDS cohort. However, EFS was equivalent when the comparison excluded ALL-NDS with favorable biologic features. OS was significantly inferior for ALL-DS.

CONCLUSIONS

The absence of favorable biologic features within ALL-DS contributes to the difference in EFS previously observed between DS and NDS SR-ALL cohorts.