Flow cytometric analysis of cerebrospinal fluid improves detection of leukaemic blasts in infants with acute lymphoblastic leukaemia.

Infants with acute lymphoblastic leukaemia (ALL) have a high frequency of central nervous system (CNS) involvement. Flow cytometric analysis of cerebrospinal fluid (CSF) was recently demonstrated to be a sensitive method for detecting CNS involvement in childhood ALL. In the present study, CSF from 14 infants was collected at routine lumbar punctures and analysed by multicolour flow cytometry. At initial diagnosis, leukaemic blasts were detected in CSF by flow cytometry in 11 patients (78·6%) compared to seven patients (50%) by cytospin. Larger studies are needed to determine if CSF flow cytometry has prognostic value in infant ALL.

Successful treatment with placenta-derived decidual stromal cells in a pediatric patient with life-threatening acute gastrointestinal graft-versus-host disease.

Severe aGvHD is a life-threatening complication after allogeneic HSCT. The GI tract is considered to play a key role in aGvHD, where the disease process can start and is one of the major target organs. Here, we present a case of a one-year-old child with a life-threatening GI-aGvHD stage IV, post-HSCT, resistant to steroids and MMF for 4 weeks. He was successfully treated with placenta-derived DSC.

Children with cancer share their views: tell the truth but leave room for hope.

AIM: One in five children diagnosed with cancer will die from the disease. The aim of the study was to explore how children with cancer want to receive bad news about their disease, such as when no more treatment options are available. METHODS: We conducted individual interviews with ten children with cancer, aged seven to 17 years, at a single paediatric oncology unit in central Sweden. Interviews were audio-taped and analysed with systematic text condensation. Bad news was defined as information about a potentially fatal outcome, such as a disease relapse, or information that the treatment administered was no longer working and that there was no more treatment possible. RESULTS: All children expressed that they wanted truthful information and they did not want to be excluded from bad news regarding their illness. They wanted to be informed as positively as possible, allowing them to maintain hope, and in words that they could understand. They also wanted to receive any bad news at the same time as their parents. CONCLUSION: Children with cancer want to be fully informed about their disease, but they also wanted it to be relayed as positively as possible so that they could stay hopeful.

The mutational landscape in pediatric acute lymphoblastic leukemia deciphered by whole genome sequencing.

Genomic characterization of pediatric acute lymphoblastic leukemia (ALL) has identified distinct patterns of genes and pathways altered in patients with well-defined genetic aberrations. To extend the spectrum of known somatic variants in ALL, we performed whole genome and transcriptome sequencing of three B-cell precursor patients, of which one carried the t(12;21)ETV6-RUNX1 translocation and two lacked a known primary genetic aberration, and one T-ALL patient. We found that each patient had a unique genome, with a combination of well-known and previously undetected genomic aberrations. By targeted sequencing in 168 patients, we identified KMT2D and KIF1B as novel putative driver genes. We also identified a putative regulatory non-coding variant that coincided with overexpression of the growth factor MDK. Our results contribute to an increased understanding of the biological mechanisms that lead to ALL and suggest that regulatory variants may be more important for cancer development than recognized to date. The heterogeneity of the genetic aberrations in ALL renders whole genome sequencing particularly well suited for analysis of somatic variants in both research and diagnostic applications.

Prognostic implications of mutations in NOTCH1 and FBXW7 in childhood T-ALL treated according to the NOPHO ALL-1992 and ALL-2000 protocols.

BACKGROUND: In children, T-cell acute lymphoblastic leukemia (T-ALL) has inferior prognosis compared with B-cell precursor ALL. In order to improve survival, individualized treatment strategies and thus risk stratification algorithms are warranted, ideally already at the time of diagnosis. PROCEDURE: We analyzed the frequency and prognostic implication of mutations in NOTCH1 and FBXW7 in 79 cases of Swedish childhood T-ALL treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL-1992 and ALL-2000 protocols. In a subgroup of patients, we also investigated the functional relevance of NOTCH1 mutations measured as expression of the HES1, MYB, and MYC genes. RESULTS: Forty-seven of the cases (59%) displayed mutations in NOTCH1 and/or FBXW7. There was no difference in overall (P = 0.14) or event-free survival (EFS) (P = 0.10) in patients with T-ALL with mutation(s) in NOTCH1/FBXW7 compared with patients with T-ALL without mutations in any of these genes. T-ALL carrying NOTCH1 mutations had increased HES1 and MYB mRNA expression (HES1 9.2 ± 1.9 (mean ± SEM), MYB 8.7 ± 0.8 (mean ± SEM)) compared to T-ALL with wild-type NOTCH1 (HES1 1.8 ± 0.7, MYB 5.1 ± 1.2, P = 0.02 and 0.008, respectively). In cases of T-ALL with high HES1 expression, improved overall (P = 0.02) and EFS (P = 0.028) was seen. CONCLUSIONS: Increased NOTCH activity, reflected by increased HES1 expression, is associated with improved outcome in pediatric T-ALL, but its role as a diagnostic tool or a therapeutic target in future clinical treatment protocols remains to be elucidated.

Transition to noncurative end-of-life care in paediatric oncology--a nationwide follow-up in Sweden.

AIM: To estimate whether and when children dying from a malignancy are recognized as being beyond cure and to study patterns of care the last weeks of life. METHODS: A nationwide retrospective medical record review was conducted. Medical records of 95 children (60% of eligible children) who died from a malignancy 2007-2009 in Sweden were studied. RESULTS: Eighty-three children (87%) were treated without curative intent at the time of death. Children with haematological malignancies were less likely to be recognized as being beyond cure than children with brain tumours [relative risks (RR) 0.7; 95% confidence interval (CI) 0.6-0.9] or solid tumours (RR 0.8; 0.6-1.0). The transition to noncurative care varied from the last day of life to over four years prior to death (median 60 days). Children with haematological malignancies were treated with a curative intent closer to death and were also given chemotherapy (RR 5.5; 1.3-22.9), transfusions (RR 2.0; 1.0-4.0) and antibiotics (RR 5.3; 1.8-15.5) more frequently than children with brain tumours the last weeks of life. CONCLUSION: The majority of children dying from a malignancy were treated with noncurative intent at the time of death. The timing of a transition in care varied with the diagnoses, being closer to death in children with haematological malignancies.

Genome-wide analysis of cytogenetic aberrations in ETV6/RUNX1-positive childhood acute lymphoblastic leukaemia.

The chromosomal translocation t(12;21) resulting in the ETV6/RUNX1 fusion gene is the most frequent structural cytogenetic abnormality among patients with childhood acute lymphoblastic leukaemia (ALL). We investigated 62 ETV6/RUNX1-positive childhood ALL patients by single nucleotide polymorphism array to explore acquired copy number alterations (CNAs) at diagnosis. The mean number of CNAs was 2·82 (range 0-14). Concordance with available G-band karyotyping and comparative genomic hybridization was 93%. Based on three major protein-protein complexes disrupted by these CNAs, patients could be categorized into four distinct subgroups, defined by different underlying biological mechanisms relevant to the aetiology of childhood ALL. When recurrent CNAs were evaluated by an oncogenetic tree analysis classifying their sequential order, the most common genetic aberrations (deletions of 6q, 9p, 13q and X, and gains of 10 and 21) seemed independent of each other. Finally, we identified the most common regions with recurrent gains and losses, which comprise microRNA clusters with known oncogenic or tumour-suppressive roles. The present study sheds further light on the genetic diversity of ETV6/RUNX1-positive childhood ALL, which may be important for understanding poor responses among this otherwise highly curable subset of ALL and lead to novel targeted treatment strategies.

Is there a choice when a sibling is ill? Experiences of children and adolescents who donated stem cells to a sibling.

PURPOSE: When healthy children/adolescents are potential stem cell donors to a sibling, ethical questions arise due to reduced autonomy and dependency on their family. This study aimed to explore the experiences of children/adolescents in Sweden who donated stem cells to a severely ill sibling. METHOD: Semi-structured interviews were conducted with thirteen donors, aged 6-17 years at the time of the donation, all with surviving siblings. The interviews were transcribed verbatim and analysed using qualitative content analysis. RESULT: The main category in this study was The presumed 'choice' when a sibling is ill. The experience included being Proud without an actual choice, highlights that the donors were proud to contribute, and perceptions of a request without a choice. Focusing on the ill sibling and the outcomes reveals that they were worried and protected the sibling, and downplayed the importance of their own effort. They experienced a Need ofsupport and information, which derived from receiving information without communication about what they really needed to know, but also the importance of support through play and talk. CONCLUSION: The donation involves the young donor in the care, implying an opportunity to bring the family back together. They have no real choice, when their sibling is ill and the lack of information about possible alternatives indicate that there was no option to decline. There is also a need to focus on the experiences of young donors whose siblings died after the transplantation.

Individualized toxicity-titrated 6-mercaptopurine increments during high-dose methotrexate consolidation treatment of lower risk childhood acute lymphoblastic leukaemia. A Nordic Society of Paediatric Haematology and Oncology (NOPHO) pilot study.

This study explored the feasibility and toxicity of individualized toxicity-titrated 6-mercaptopurine (6MP) dose increments during post-remission treatment with High-dose methotrexate (HDM) (5000 mg/m(2), ×3) in 38 patients with Childhood (ALL). Patients were increased in steps of 25 mg 6MP/m(2) per day if they did not develop myelotoxicity within 2 weeks after HDM. 6MP could be increased in 31 patients (81%). Toxicity was acceptable and did not differ significantly between groups. Patients receiving 75 mg/m(2) per day had significantly shorter duration of treatment interruptions of 6MP than the remaining patients (P = 0·03). This study shows individualized toxicity-titrated 6MP dosing during consolidation is feasible without increased risk of toxicity.

In vitro cellular drug sensitivity at diagnosis is correlated to minimal residual disease at end of induction therapy in childhood acute lymphoblastic leukemia.

Leukemic cells from 85 children with newly diagnosed precursor B-lineage ALL were tested for in vitro drug sensitivity to a panel of anti-cancer drugs. Minimal residual disease (MRD) was measured by RQ-PCR. There was a significant correlation between MRD day 29 and in vitro sensitivity to prednisolone (p<0.001) and doxorubicin (p=0.017), drugs administered during induction therapy. In patients with t(12;21) (n=20), in vitro sensitivity to doxorubicin was an independent factor for MRD <0.1% (p=0.031; R(2)=0.66). Thus, data show that in vitro drug sensitivity at diagnosis is correlated to cell kill during induction therapy as measured by MRD day 29.

Thioguanine pharmacokinetics in induction therapy of children with acute myeloid leukemia.

We studied the pharmacokinetics of 6-thioguanine (6TG) in 50 children treated for newly diagnosed acute myeloid leukemia, four of them with Down syndrome (DS). They received oral 6TG 100 mg/m2 body surface area twice daily for 4 days. Etoposide, 100 mg/m2/24 h, and cytarabine, 200 mg/m2/24 h, were administered concomitantly by intravenous infusion. On day 5, doxorubicin 75 mg/m2 was given as an 8-h infusion. The concentration of thioguanine nucleotides (TGN) in erythrocytes, the active metabolites of 6TG, was determined by high-performance liquid chromatography. The mean TGN concentration from 72, 95, and 106-h samples was used as a measure of drug exposure for each individual. The median TGN concentration in non-DS children above 2 years of age was 2.30 micromol/mmol Hb (range 0.57-25.3). The TGN concentrations varied widely (30-fold) also after dose normalization. We found no correlation with demographic, clinical, or biochemical parameters, and differences in bioavailability might be the most important explanation to interpatient variability. Children with high TGN concentration tended to have longer treatment interval to the next course, but we found no correlation with our predefined parameters for clinical response, that is, remission and relapse rate. Therefore, 6TG does not seem to be a candidate for therapeutic drug monitoring by TGN measurement, at least not in the setting of short multidrug treatment courses. Children with DS had significantly higher TGN concentrations, indicating that dose reduction might be considered to reach the same drug exposure as in non-DS children.

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.

Vincristine pharmacokinetics is related to clinical outcome in children with standard risk acute lymphoblastic leukemia.

Vincristine is a key drug in the treatment of childhood and adult acute lymphoblastic leukemia (ALL), and many other childhood malignancies. Despite decades of wide clinical use, no data on the correlation between vincristine pharmacokinetics and long-term clinical outcome have been published. We here report clinical data (median follow-up time 10.5 years, range 7.3-12 years) for 86 children with B-cell precursor ALL, in whom vincristine kinetics were studied on treatment day 1. The median total plasma clearance was 429 and 331 ml/min per m(2) and the area under the plasma concentration-time curve (AUC) was 4.49 and 5.40 mg/l x min in relapse and non-relapse patients, respectively (not significant). In standard risk patients, where treatment depends more heavily on vincristine than in other subgroups, the relative risk (RR) of relapse was significantly increased for patients with clearance values above median (RR 5.2; P = 0.036), or AUC values below median (RR 5.8; P = 0.025). Our data suggest a relationship between the antileukemic effect and the systemic exposure of the drug, which warrants further studies.

Intrathecal chemoprophylaxis after HSCT in children.

At present, the literature on the efficacy and risks of i.t. chemotherapy to children after HSCT is scarce. Current practices to reduce the risk of leukemic relapse in the CNS after HSCT differ between centers of transplantation. We compared 74 patients (56 ALL/18 AML), who received i.t. therapy post-HSCT with 46 patients (36 ALL/10 AML) who did not receive post-HSCT i.t. therapy. The patients were transplanted at the University Children's Hospital, Uppsala or the Karolinska University Hospital, Huddinge, two Swedish transplantation units with different routines concerning i.t. therapy after HSCT. The primary end-point was the number of isolated CNS relapses. Secondary end-points were other types of relapse, death, and neurological complications. There was no statistically significant difference in the incidence of CNS relapses between the groups (p > 0.05). I.t. therapy did not reduce the overall incidence of isolated CNS relapse or mortality. Our study did not demonstrate a protective effect of i.t. therapy indicating that post-HSCT i.t. therapy may only be of limited use in the treatment of acute childhood leukemia. We conclude that with the risks present, i.t. therapy should be carefully evaluated, and only considered in high-risk cases.

DNA methylation holds prognostic information in relapsed precursor B-cell acute lymphoblastic leukemia.

Background: Few biological markers are associated with survival after relapse of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). In pediatric T-cell ALL, we have identified promoter-associated methylation alterations that correlate with prognosis. Here, the prognostic relevance of CpG island methylation phenotype (CIMP) classification was investigated in pediatric BCP-ALL patients. Methods: Six hundred and one BCP-ALL samples from Nordic pediatric patients (age 1-18) were CIMP classified at initial diagnosis and analyzed in relation to clinical data. Results: Among the 137 patients that later relapsed, patients with a CIMP- profile (n = 42) at initial diagnosis had an inferior overall survival (pOS5years 33%) compared to CIMP+ patients (n = 95, pOS5years 65%) (p = 0.001), which remained significant in a Cox proportional hazards model including previously defined risk factors. Conclusion: CIMP classification is a strong candidate for improved risk stratification of relapsed BCP-ALL.

Deep targeted sequencing in pediatric acute lymphoblastic leukemia unveils distinct mutational patterns between genetic subtypes and novel relapse-associated genes.

To characterize the mutational patterns of acute lymphoblastic leukemia (ALL) we performed deep next generation sequencing of 872 cancer genes in 172 diagnostic and 24 relapse samples from 172 pediatric ALL patients. We found an overall greater mutational burden and more driver mutations in T-cell ALL (T-ALL) patients compared to B-cell precursor ALL (BCP-ALL) patients. In addition, the majority of the mutations in T-ALL had occurred in the original leukemic clone, while most of the mutations in BCP-ALL were subclonal. BCP-ALL patients carrying any of the recurrent translocations ETV6-RUNX1, BCR-ABL or TCF3-PBX1 harbored few mutations in driver genes compared to other BCP-ALL patients. Specifically in BCP-ALL, we identified ATRX as a novel putative driver gene and uncovered an association between somatic mutations in the Notch signaling pathway at ALL diagnosis and increased risk of relapse. Furthermore, we identified EP300, ARID1A and SH2B3 as relapse-associated genes. The genes highlighted in our study were frequently involved in epigenetic regulation, associated with germline susceptibility to ALL, and present in minor subclones at diagnosis that became dominant at relapse. We observed a high degree of clonal heterogeneity and evolution between diagnosis and relapse in both BCP-ALL and T-ALL, which could have implications for the treatment efficiency.

Genome-wide signatures of differential DNA methylation in pediatric acute lymphoblastic leukemia.

BACKGROUND: Although aberrant DNA methylation has been observed previously in acute lymphoblastic leukemia (ALL), the patterns of differential methylation have not been comprehensively determined in all subtypes of ALL on a genome-wide scale. The relationship between DNA methylation, cytogenetic background, drug resistance and relapse in ALL is poorly understood. RESULTS: We surveyed the DNA methylation levels of 435,941 CpG sites in samples from 764 children at diagnosis of ALL and from 27 children at relapse. This survey uncovered four characteristic methylation signatures. First, compared with control blood cells, the methylomes of ALL cells shared 9,406 predominantly hypermethylated CpG sites, independent of cytogenetic background. Second, each cytogenetic subtype of ALL displayed a unique set of hyper- and hypomethylated CpG sites. The CpG sites that constituted these two signatures differed in their functional genomic enrichment to regions with marks of active or repressed chromatin. Third, we identified subtype-specific differential methylation in promoter and enhancer regions that were strongly correlated with gene expression. Fourth, a set of 6,612 CpG sites was predominantly hypermethylated in ALL cells at relapse, compared with matched samples at diagnosis. Analysis of relapse-free survival identified CpG sites with subtype-specific differential methylation that divided the patients into different risk groups, depending on their methylation status. CONCLUSIONS: Our results suggest an important biological role for DNA methylation in the differences between ALL subtypes and in their clinical outcome after treatment.

In vitro cellular drug resistance adds prognostic information to other known risk-factors in childhood acute lymphoblastic leukemia.

Leukemic cells from 230 children with newly diagnosed B-cell precursor ALL were tested for in vitro drug resistance to a panel of anti-cancer drugs. Minimal residual disease (MRD) was measured by RQ-PCR. During follow-up, 24 relapses occurred in the 159 children with MRD <0.1% day 29. The risk of any relapse was correlated to vincristine and doxorubicin resistance, with a relative risk of 3.7 (95% CI 1.3-10.5; p=0.016) for patients resistant to both drugs. There was a significant correlation also for the subgroup with extra-medullary relapses. Our findings indicate that analysis of drug resistance can add prognostic information to other known risk-factors including MRD.