Detection of Five Common Fusion Oncogenes in Pakistani Children with Acute Lymphoblastic Leukemia and Their Association with Clinical Pattern and Treatment Outcome

Abstract Abstract 5124 Background & Objectives: Acute lymphoblastic leukemia (ALL) is a complex genetic disease involving many fusion oncogenes (FGs) (Xu et al., 2012). The frequency of various FO can vary in different ethnic groups & these FGs have important implications for prognosis & treatment outcome (van-Dongen et al, 1999). Methods: We studied FGs in 101 pediatric ALL patients using Interphase FISH & RT-PCR (van-Dongen et al, 1999), & their association with clinical features & treatment outcome. Results: Five most common FGs i. e. BCR-ABL [t(9;22)], TCF3-PBX1 [t(1;19)], ETV6-RUNX1 [t(12;21)], MLL-AF4 [t(4;11)] & SIL-TAL1 (del 1p32) were found in 89/101 (88. 1%) patients. Frequency of BCR-ABL was 44. 5% (45/101) (Table 1). BCR-ABL positive patients had a significantly lower survival (43. 73 ± 4. 24 weeks) (Figure 1)& higher white cell count as compared to others except patients with MLL-AF4. The highest relapse-free survival (RFS) was documented in ETV6-RUNX1 (14. 167 months) followed closely by those cases in which no gene was detected (13/100). RFS in BCR-ABL, MLL-ASF4, TCF-PBX4 & SIL-TAL1 was less than 10 months (7. 994, 3. 559, 5. 500 & 8. 080 months respectively) (Figure 2 & 3). BCR-ABL: Frequency of occurrence was directly proportional to age (3 less than 2 year age group, 16 in the 2–7 year age group & 26 in the older than 7 group. Total leukocyte count (TLC) was higher when compared to patients with other oncogenes. Organomegaly was not common. BCR-ABL positivity was associated with low remission rates & shortened survival. ETV6-RUNX1: The median age of the patients was 1. 85 years. The gene frequency was highest in patients younger than 2 years. TLC was not very high & patients had a good prognosis. MLL-AF4: 17 patients had MLL-AF4 gene rearrangement with a median age of 9 years. Five patients were younger than 2 years, two between 2 & 7 years, & ten patients were in the 7–15 age group. Majority of our patients were older unlike the usual occurrence where most of the patients are infants. TCF3-PBX1: This FG occurs in around 2% of patients. Only two female patients were diagnosed with this translocation. Both the patients were over 2 years of age. It was associated with an inferior outcome in the context of response to chemotherapy & a higher risk of CNS relapse although small numbers preclude any firm conclusions. SIL-TAL1: Patients were older than 2 years, with the majority falling in the age range 7 to 15 years. The immunophenotype data were available in all SIL-TAL1 patients showing this fusion gene was associated with T-ALL with organomegaly being observed frequently. Discussion & Conclusion: This is the first study from Pakistan correlating molecular markers with disease biology & treatment outcome in pediatric ALL. Our study revealed the highest reported frequency of BCR-ABL FO in pediatric ALL, in consistent with various other reports from Pakistan & rest of the world ((Iqbal & Akhtar, 2007; Faiz et al., 2011; (Gaynon et al., 1997; Iacobucci et al., 2012).) which, consequently, was associated with poor overall survival. The data indicates an immediate need for incorporation of tyrosine kinase inhibitors in the treatment of BCR-ABL+ pediatric ALL in this population & the development of facilities for stem cell transplantation. Disclosures: No relevant conflicts of interest to declare.

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Low Epression of MiR-18a Distinguishes Pediatric and Adult Acute Lymphoblastic Leukemia from Each Other

Blood ◽

10.1182/blood.v126.23.4991.4991 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4991-4991

Author(s):

Neda Mosakhani ◽

Mohamed El Missiry ◽

Emmi Vakkila ◽

Päivi Heikkilä ◽

Sakari Knuutila ◽

...

Keyword(s):

Bone Marrow ◽

Acute Lymphoblastic Leukemia ◽

Immune Cell ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Tissue Samples ◽

Inflammatory Microenvironment ◽

Qrt Pcr ◽

Response To Chemotherapy ◽

Pediatric All

Abstract In several adult solid cancers the presence or absence of an inflammatory microenvironment has turned out to be an important prognostic factor. Acute lymphoblastic leukemia (ALL) is seen in both adults and children but the response to chemotherapy and survival is significantly worse in adults than children. Therefore, we wanted to study whether the expression of immune system associated molecular markers would be different in adult and pediatric ALL patients at the time of diagnosis. IDO and FOXP3 were studied from paraffin embedded tissue samples by immunohistochemistry in 12 pediatric and 10 adult bone marrow samples. Inflammation associated miRNA analysis were performed in 19 adult and 79 pediatric ALL patients and involved miR-10, miR-15, miR-16, miR-17-92 cluster, miR-33, miR-146a, miR-150, miR-155, miR-181a, miR-222, miR-223, and miR-339. miRNAs were first analysed by Agilent's miRNA microarray and thereafter validated by qRT-PCR. miRNAs not expressed in at least 75% of one group of samples were excluded. Significance (p <0.05; q<0.1) of differential expression was estimated by t-test for those miRNAs with at least a 2.0 fold change. Sufficient RNA for qRT-PCR was available for 42 pediatric and 19 adult patients. The adult and pediatric ALL patients had quantitatively and qualitatively similar expression of IDO and FOXP3 in leukemic bone marrow samples (p=0.26 and 0.74, respectively). Out of studied miRNAs only miR-18a differed significantly in microarray analysis between adult and pediatric ALL being lower in children (FC -3.74; p 0,0037). Results were confirmed by qRT-PCR (upregulated in adults, FC 3.71, p 0.003161). The other members of the miR-17-92 cluster did not differ significantly. We conclude that pediatric and adult ALL patients have remarkably similar pattern of immune cell associated markers in bone marrow at diagnosis. This is in line with recent evidence that the outcome of the adult ALL patients can be significantly improved if treated with pediatric protocols. However, the low expression of miR-18a in pediatric ALL is interesting and demands further studies. Disclosures No relevant conflicts of interest to declare.

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The Heterogeneous Fusion Gene Landscape in Pediatric Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v128.22.4081.4081 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4081-4081

Author(s):

Yanara Marincevic-Zuniga ◽

Johan Dahlberg ◽

Sara Nilsson ◽

Amanda Raine ◽

Jonas Abrahamsson ◽

...

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Acute Lymphoblastic Leukemia ◽

Gene Fusion ◽

Conflicts Of Interest ◽

Fusion Gene ◽

Lymphoblastic Leukemia ◽

Fusion Genes ◽

Fusion Transcripts ◽

Pediatric All

Abstract Background: Next generation sequencing allows for the detection of expressed fusion transcripts across the transcriptome and has spurred the discovery of many novel chimeric transcripts in various cancers. Structural chromosomal rearrangements that lead to fusion transcripts are a hallmark of acute lymphoblastic leukemia (ALL) and serve as markers for diagnosis and stratification of pediatric ALL patients into prognostically relevant subgroups. Improved delineation of structural alterations in ALL could provide additional information for prognosis in ALL and for improved stratification of patients into treatment groups. Methods: To identify novel fusion transcripts in primary pediatric ALL cells we performed whole transcriptome sequencing of 134 BCP and T-ALL patient samples collected at diagnosis. Our study include samples from patients with the well-known ALL subtypes t(12;21)ETV6-RUNX1, high hyperdiploid (51-67 chromosomes), t(9;22)BCR-ABL1, 11q23/MLL and dic(9;20), in addition to patients with undefined karyotype or non-recurrent cytogenetic aberrations ("undefined" and "other") (n=58). FusionCatcher was used for the detection of somatic fusion genes, followed by a stringent filtering pipeline including gene fusion validation by Sanger sequencing in order to reduce the number of false positives. Principal component analysis (PCA) of patients with fusion genes was performed using genome wide gene expression levels and DNA methylation levels (Infinium HumanMethylation450 bead array). Results: We identified and validated 60 unique fusion events in almost half of the analyzed patients (n=69). Of the identified fusion genes, 60% have not previously been reported in ALL or other forms of cancer. The majority of the fusion genes were found in a single patient, but 23% were recurrent, including known ALL fusion genes (n=10) and novel fusion genes (n=7). We found that BCP-ALL samples displayed a higher number of validated fusion genes (54%) compared to the T-ALL samples (28%) moreover in BCP-ALL patients with "other" and "undefined" karyotypes, we detected fusion genes in 71% and 61% of the samples, respectively. High hyperdiploid patients had the lowest rate of validated fusion genes (24%) compared to the other well-known subtypes, where we detected subtype-associated fusion genes in 97% of cases. We also identified promiscuous fusion gene partners, such as ETV6, RUNX1, PAX5 and ZNF384 that fused with up to five different genes. Interestingly, PCA revealed molecularly distinct gene expression and DNA methylation signatures associated with these fusion partners. Conclusion: RNA-sequencing of pediatric ALL cells revealed a detailed view of the heterogeneous fusion gene landscape, identifying both known and novel fusion genes. By grouping samples based on recurrent gene fusion partners we are able to find shared gene expression and DNA methylation patterns compared to other subtypes of ALL, suggesting a shared molecular etiology within these distinct subgroups, offering novel insights into the delineation of fusion genes in ALL. Disclosures No relevant conflicts of interest to declare.

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Targeting Kinase-activating Genetic Lesions to Improve Therapy of Pediatric Acute Lymphoblastic Leukemia

Current Medicinal Chemistry ◽

10.2174/0929867324666170727101932 ◽

2018 ◽

Vol 25 (24) ◽

pp. 2811-2825 ◽

Cited By ~ 2

Author(s):

Raffaella Franca ◽

Natasa K. Kuzelicki ◽

Claudio Sorio ◽

Eleonora Toffoletti ◽

Oksana Montecchini ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Fusion Gene ◽

Hematologic Malignancy ◽

Lymphoblastic Leukemia ◽

Point Of View ◽

Lymphoid Cells ◽

Gene Encoding ◽

Pediatric All ◽

Blast Cells ◽

Tk Inhibitors

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children, characterized by an abnormal proliferation of immature lymphoid cells. Thanks to risk-adapted combination chemotherapy treatments currently used, survival at 5 years has reached 90%. ALL is a heterogeneous disease from a genetic point of view: patients’ lymphoblasts may harbor in fact several chromosomal alterations, some of which have prognostic and therapeutic value. Of particular importance is the translocation t(9;22)(q34;q11.2) that leads to the formation of the BCR-ABL1 fusion gene, encoding a constitutively active chimeric tyrosine kinase (TK): BCR-ABL1 that is present in ~3% of pediatric ALL patients with B-immunophenotype and is associated with a poor outcome. This type of ALL is potentially treatable with specific TK inhibitors, such as imatinib. Recent studies have demonstrated the existence of a subset of BCR-ABL1 like leukemias (~10-15% of Bimmunophenotype ALL), whose blast cells have a gene expression profile similar to that of BCR-ABL1 despite the absence of t(9;22)(q34;q11.2). The precise pathogenesis of BCR-ABL1 like ALL is still to be defined, but they are mainly characterized by the activation of constitutive signal transduction pathways due to chimeric TKs different from BCR-ABL1. BCR-ABL1 like ALL patients represent a group with unfavorable outcome and are not identified by current risk criteria. In this review, we will discuss the design of targeted therapy for patients with BCR-ABL1 like ALL, which could consider TK inhibitors, and discuss innovative approaches suitable to identify the presence of patient’s specific chimeric TK fusion genes, such as targeted locus amplification or proteomic biosensors.

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IKZF1 Deletion Is An Independent Predictor of Outcome In Pediatric Acute Lymphoblastic Leukemia Treated According to the ALL-BFM 2000 Protocol

Blood ◽

10.1182/blood.v116.21.409.409 ◽

2010 ◽

Vol 116 (21) ◽

pp. 409-409

Author(s):

Petra Breithaupt ◽

Barbara Meissner ◽

Martin Zimmermann ◽

Anja Möricke ◽

André Schrauder ◽

...

Keyword(s):

Treatment Outcome ◽

High Risk ◽

Cox Regression ◽

Conflicts Of Interest ◽

Residual Disease ◽

Risk Group ◽

Independent Predictor ◽

Lymphoblastic Leukemia ◽

Time Points ◽

Pediatric All

Abstract Abstract 409 Alteration of the IKZF1 gene – encoding the transcription factor IKAROS, a key player in lymphoid development and tumor suppression – has been reported to be associated with a poor outcome in pediatric precursor B-cell ALL, especially in cases positive for the BCR-ABL1 fusion gene. In order to assess the prognostic value of IKZF1 deletions in a representative cohort of pediatric ALL patients treated on the German ALL-BFM 2000 study protocol, we screened 409 patients by applying a multiplex ligation-dependent probe amplification (MLPA) assay covering all eight IKZF1 exons (P335-A3 ALL-IKZF1 probemix; MRC-Holland, Amsterdam, The Netherlands). In ALL-BFM 2000, risk group stratification (standard, SR; intermediate, MR; high, HR) was based on minimal residual disease (MRD) analysis at two different time points (TP) and required two MRD targets with sensitivities of ≤10−4 (Flohr et al. Leukemia 2008). SR patients were MRD-negative on treatment days 33 (TP1) and 78 (TP2). HR patients had residual disease (≥10−3) at TP2. MRD MR patients had positive MRD detection at either one and or both time points but at a level of <10−3 at TP2. Although MRD-based stratification criteria were introduced in ALL-BFM 2000, established high-risk parameters were also retained: patients with prednisone poor-response or ≥5% leukemic blasts in the bone marrow on day 33 or positivity for a t(9;22) or t(4;11) or their molecular equivalents (BCR/ABL1 or MLL/AF4 fusion RNA) were stratified into the high-risk group independent of their MRD results. First results on MRD and outcome were published earlier (Conter et al. Blood 2010). Out of the 409 patients analyzed in our study, 46 (11%) displayed a deletion in at least one of the eight IKZF1 exons. Forty-three out of the 46 cases showed heterozygous deletions, while 3 patients displayed homozygous loss of IKZF1 exons. MLPA results of 11 patients were validated with results derived from copy number/LOH analyses using Affymetrix SNP 6.0 arrays. IKZF1 deletion was significantly more common in precursor B compared to T cell ALL (13% vs. 4%, P = 0.03) and less frequent in TEL/AML1-positive ALL (3% vs. 13%, P = 0.004). Out of 11 BCR/ABL1-positive samples, only two were characterized by an IKZF1 deletion. Forty-four patients with IKZF1-deleted ALL had results of MRD analyses available for both informative time points (day 33 after induction and day 78 after consolidation). Despite a trend towards increasing incidence of IKZF1 deletion in patients with slow response, the distribution of IKZF1-deleted ALL patients over the risk groups was not significantly different from non-deleted ALL (SR: 40.9 vs. 41.9; MR: 45.5 vs. 52.3; HR: 13.6 vs. 5.7%; P = 0.153). Regarding treatment outcome, patients with an IKZF1 deletion had a significantly lower 5-year event-free survival (EFS) compared to non-deleted patients (0.78±0.06 vs. 0.86±0.02; P = 0.015). This result was due to a higher cumulative incidence of relapses in IKZF1-deleted patients (0.16±0.05 vs. 0.10±0.02; P = 0.031). In multivariate Cox regression analyses including known prognostic variables (gender, immunophenotype, WBC count at diagnosis, TEL/AML1 status, risk group criteria of ALL-BFM 2000), IKZF1 deletion conferred a risk of 2.16 (95% confidence interval 1.14 – 4.10; P = 0.018) for an event when compared to non-deleted patients. We conclude that IKZF1 deletion is an independent predictor of treatment outcome for patients enrolled on the ALL-BFM 2000 protocol and represents a candidate marker to be integrated in future algorithms for early risk stratification in pediatric ALL. Disclosures: No relevant conflicts of interest to declare.

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Triptolide Induces Apoptosis In Acute Lymphoblastic Leukemia Cells by Inhibition of the Oncoprotein MDM2

Blood ◽

10.1182/blood.v116.21.4934.4934 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4934-4934

Author(s):

Mei Huang ◽

Lubing Gu ◽

Muxiang Zhou

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Biological Action ◽

Leukemic Cells ◽

Transcriptional Level ◽

Antitumor Effects ◽

Mdm2 Expression ◽

Pediatric All ◽

Chinese Plant

Abstract Abstract 4934 Triptolide, a nature product derived from the Chinese plant Tripterygium wilfordii, is reported to exhibit antitumor effects in a broad range of cancers. Recent studies indicate that the antitumor activity of triptolide is associated with its biological action to inhibit expression of many oncoproteins and anti-apoptotic or survival factors that were expressed in the cancer cells. Herein, we demonstrate that triptolide induces apoptosis in a subgroup of acute lymphoblastic leukemia (ALL) cells that overexpress MDM2 oncoprotein by inhibiting the MDM2 expression. In pediatric ALL, overexpression of MDM2 by leukemic cells is typically associated with a wild-type (wt) p53 phenotype and resistance to conventional chemotherapeutic drugs such as doxorubicin. In the present study, we evaluated the role of triptolide in regulating MDM2 and in inducing apoptosis, as compared to doxorubicin, using ALL lines and primary ALL samples. In contrast to doxorubicin, which induced p53 activation and a subsequent upregulation of MDM2, triptolide strongly induced persistent inhibition of MDM2 followed by a steady-state activation of p53, which resulted in potent apoptosis of the MDM2-overexpressing ALL cells tested, even if they were doxorubicin-resistant. We discovered that triptolide's inhibition of MDM2 in ALL cells occurred at the post-transcriptional level through inhibition of mRNA synthesis. Because p53 function is inhibited by MDM2 in chemoresistant/MDM2-overexpressing ALL cells, potent killing of these cells by triptolide suggests that this naturally-derived agent may be a novel therapeutic for refractory ALL. Disclosures: No relevant conflicts of interest to declare.

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Aggravated Bone Density Decline after Symptomatic Osteonecrosis in Children with Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v124.21.2260.2260 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2260-2260

Author(s):

Marissa den Hoed ◽

S.M.F. Pluijm ◽

Mariël L. Te Winkel ◽

Hester A. de Groot-Kruseman ◽

Marta Fiocco ◽

...

Keyword(s):

Bone Mineral Density ◽

Acute Lymphoblastic Leukemia ◽

Side Effects ◽

Bone Mineral ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Bone Destruction ◽

Mineral Density ◽

Pediatric All ◽

Cessation Of Treatment

Abstract Background: Osteonecrosis (ON) and decline of bone mineral density (BMD) are serious side effects during and after treatment of childhood acute lymphoblastic leukemia (ALL). It is unknown whether ON and low BMD co-occur in the same patients, and whether these two osteogenic side effects can influence each other’s development during pediatric ALL treatment. Methods: BMD and the incidence of symptomatic ON were prospectively assessed in 466 patients with ALL (4-18 years of age) treated according to the dexamethasone-based Dutch Child Oncology Group-ALL9 protocol. Symptomatic ON was defined as persistent pain in arms or legs not caused by vincristine administration, and confirmed by magnetic resonance imaging. Bone mineral density of the lumbar spine (BMDLS) (n=466) and of the total body (BMDTB) (n=106) were measured by dual X-ray absorptiometry at ALL diagnosis, after 32 weeks of treatment, at cessation of treatment (109 weeks) and 1 year after cessation of treatment. BMD was expressed as age-matched and gender-matched standard deviation scores (SDS; Z-score). Multivariate linear mixed models were adjusted for age at diagnosis. Results: Thirty patients (6.4%) suffered from ON. At cessation of treatment, mean BMDLS was -1.28 SDS (SD: 1.27, n=332; p<0.01) and BMDTB was -0.74 SDS (SD: 1.29, n=65; p<0.01) lower in ALL patients compared to their healthy peers. At baseline, BMDLS and BMDTB did not differ between patients who developed or who did not develop ON (mean BMDLS ON+: -0.90 vs. ON-: -1.14, p=0.36; mean BMDTB ON+: 0.07 vs. ON-: 0.25 p=0.65). At cessation of treatment, patients with ON seem to have a trend for a lower mean BMDLS (ON+: -1.68 vs. ON-: -1.31, p=0.18) and they have a lower mean BMDTB (ON+: -1.91 vs. ON-: -0.59, p=0.01) than patients without ON. Multivariate analyses showed that BMDTB change during follow-up was significantly different for patients with ON than without ON (interaction group time, p=0.04). Between BMD measurements before and after the diagnosis, patients with ON seemed to have a more rapid decline of BMDTB than in patients of the same age without ON (mean BMDTB difference -1.13 vs. -0.62, p=0.10). Conclusion: We conclude that symptomatic ON and low BMD during antileukemic treatment co-occur in pediatric ALL patients. BMD status at ALL diagnosis does not seem to precede ON. However, the development of ON seems to aggravate BMD decline during antileukemic treatment, most likely due to bone destruction and the advised physical immobilization. Disclosures No relevant conflicts of interest to declare.

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LDL Discordance in Pediatric Survivors of Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v124.21.6003.6003 ◽

2014 ◽

Vol 124 (21) ◽

pp. 6003-6003

Author(s):

Galit Rosen ◽

Gabriel Q Shaibi

Keyword(s):

Cardiovascular Disease ◽

Acute Lymphoblastic Leukemia ◽

Disease Risk ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Cardiovascular Disease Risk ◽

Heart Association ◽

Cardiac Risk ◽

Cardiac Events ◽

Pediatric All

Abstract Background: Survivors of childhood acute lymphoblastic leukemia (ALL) have a four-fold excess risk of mortality secondary to cardiovascular events compared to the general population. While it is well-known that LDL has a role in atherogenesis and subsequent cardiac events, recent studies consistently show that LDL particle number (LDLp) is a stronger, independent predictor of coronary heart disease in adults compared to LDL-cholesterol (LDLc), especially when the values are discordant. There is emerging evidence that LDL discordance also occurs in children. We studied this phenomenon in pediatric ALL survivors and identify associated risk factors. Methods: Complete data were available from 64 patients enrolled in the Phoenix Children’s Hospital pediatric cancer survivorship registry. Patients were 12.9±3.5 years of age (range: 7.7-22.7 years) with a mean time off therapy of 5.5±2.6 years (range 2.3-11.4 years). LDLc and LDLp were assessed by NMR spectroscopy. Patients were assessed by a registered dietician for calcium, fat, and fruit intake as well as physical activity. Ideal LDLc and LDLp were defined as <160 mg/dL and <1600 nmol/L, respectively, based on American Heart Association guidelines for people with standard cardiac risk. Discordance was classified based on ideal vs. not-ideal status for each parameter. Results: Mean BMI was 22.7±5.7 kg/m2 (range 14-38 kg/m2); mean BMI percentile was 73.1±26.1% (0.9-99.5%) with 42% of patients considered overweight or obese at the time of evaluation. Mean LDLc and LDLp were 79±25.5 mg/dL (29-164 nmol/L) and 1124±517 nmol/L (411-2837 nmol/L), respectively, with 89% (n=56) of survivors exhibiting ideal LDLc and 47% (n=30) of survivors exhibiting ideal LDLp. In a subgroup of patients with ideal LDLc, 40.6% (n=26) exhibited not-ideal LDLp and were classified as discordant. Regression analysis showed that after adjusting for age and gender, BMI (p<0.00001) and LDLc (p<0.00001) were significant independent predictors of LDLp while lifestyle factors and time off therapy were not significant predictors of LDLp. When patients were grouped as concordant (ideal LDLc and LDLp, n=30) or discordant (ideal LDLc and elevated LDLp, n=25), BMI was 17.6% higher in the discordant group (25.0±5.4 kg/m2 vs. 20.6±5.0 kg/m2, p=0.003). Conclusion: In this population of pediatric ALL survivors, LDLc measurements may not provide a complete assessment of cardiovascular disease risk. Given that LDLp is an early predictor of cardiovascular outcomes, conventional lipid testing may underestimate the true cardiovascular disease risk in ALL survivors. Survivors may benefit from early, expanded screening and targeted intervention. Further studies should focus on the broader pathophysiology of cardiovascular disease in pediatric ALL survivors. Disclosures No relevant conflicts of interest to declare.

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Genetic and Metabolic Determinants of Methotrexate Induced Mucositis in Pediatric Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v124.21.939.939 ◽

2014 ◽

Vol 124 (21) ◽

pp. 939-939

Author(s):

Marissa den Hoed ◽

E. Lopez-Lopez ◽

Mariël L. Te Winkel ◽

Wim Tissing ◽

Jasmijn de Rooij ◽

...

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Conflicts Of Interest ◽

Lymphoblastic Leukemia ◽

Plasma Homocysteine ◽

Nucleotide Polymorphisms ◽

Pediatric Acute Lymphoblastic Leukemia ◽

Plasma Folate ◽

Pediatric All ◽

Erythrocyte Folate ◽

Grade 3

Abstract Introduction: Methotrexate (MTX) is an important and effective chemotherapeutic drug in the treatment of pediatric acute lymphoblastic leukemia (ALL). However MTX can induce toxicity, which can lead to amendments of treatment and subsequent impaired survival. The aim of this study was to identify metabolic and genetic determinants of MTX toxicity. Patients and Methods: In this prospective study, 134 Dutch pediatric ALL patients were treated with four high dosages MTX (HD-MTX: 5 g/m2) every other week according to the DCOG-ALL10 protocol. Toxicity was prospectively scored and a National Cancer Institute (NCI) grade ≥3 was considered clinically relevant toxicity. Plasma MTX levels were measured at 24 and 48 hours after each HD-MTX infusion. Erythrocyte folate, plasma folate and plasma homocysteine levels were determined at the start of protocol M. Seventeen single nucleotide polymorphisms (SNPs) in 7 candidate genes in the MTX pathway were analyzed. Results: Grade ≥3 mucositis occurred in 20% of the patients, skin toxicity in 7%, diarrhea in 3%, and neurotoxicity in 3%. Mucositis occurred especially after the first course compared to the other courses (p=0.006). Mucositis was not associated with plasma MTX, plasma folate or plasma homocysteine levels. Patients with mucositis had higher baseline levels of erythrocyte folate (median 1.2 μmol/L vs. 1.4 μmol/L, p<0.008). Wildtype rs7317112 in the ABCC4 gene was the only SNP associated with a higher frequency of mucositis (AA (39%) vs. AG/GG (15%), p=0.016). Conclusion: Mucositis is the most frequent occurring toxicity during the HD-MTX phase in pediatric ALL treatment, and occurs especially after the first MTX course. Only a higher baseline erythrocyte folate, which reflects the accumulation of MTX polyglutamates in mucosal cells, and the wild-type variant of rs7317112 SNP in ABCC4 were determinants of mucositis in pediatric ALL during MTX-HD treatment. Disclosures No relevant conflicts of interest to declare.

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Novel MEIS1-FOXO1 Fusion Gene in a Case of Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood-2018-99-116354 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 5283-5283

Author(s):

Chuang Jiang ◽

Jiabi Qian ◽

Wenge Hao ◽

Wei LIU ◽

Shuhong Shen ◽

...

Keyword(s):

Cell Cycle ◽

Acute Lymphoblastic Leukemia ◽

B Cell ◽

Conflicts Of Interest ◽

Residual Disease ◽

Fusion Gene ◽

Lymphoblastic Leukemia ◽

Functional Study ◽

Cell Precursor ◽

Foxo1 Gene

Abstract Background: Thanks to the total therapy and systemic basic-translation research, the overall survival rate in children with acute lymphoblastic leukemia (ALL) has dramatically improved to almost 90% over these past few decades. FOXO1 gene belongs to the forkhead family of transcription factors, which play roles in myogenic growth and differentiation. Translocation of FOXO1 with PAX3 has been reported in pediatric alveolar rhabdomyosarcoma. In B-cell precursor ALL, two cases with FOXO1 fusions have been identified already, while its function on ALL remains unknown. Here, we report a novel MEIS1-FOXO1 fusion gene in a case with B-ALL. Methods: Flowcytometery, karyotype, RT-PCR and fluorescence in were employed, MEIS1-FOXO1 was identified as novel fusion gene in a case of pediatric BCP-ALL. Using IL-3 dependent BaF3 cells as study model to test the leukemia transformation potential of MEIS1-FOXO1. Results: A novel MEIS1-FOXO1 fusion was identified in one cease of pediatric B-ALL. Panel next generation sequencing (NGS) showed that the leukemia clone had concurrent NRASG12D, TP53R273H, WHSC1E1099K, ABCC1R1166X, PHGR1H37P, HOXA3P219L and DSTP4606L somatic mutation. This patient was enrolled in CCCG-ALL2015 clinical trial (ChiCTR-IPR-14005706) and achieved completed remission and low minimal residual disease (MRD) level (MRD<0.01%) at day 19 from induction therapy. Functional study showed that MEIS1-FOXO1 fusion gene can potentiate BaF3 cells growth independent of IL3 supplement, as compared to those without MEIS1-FOXO1 fusion transduction. In the meanwhile, we have found that MEIS1-FOXO1 fusion gene can drive cells into S-phase with concurrent decreased G0/G1 phase, which might be its oncogenic role in leukemogenesis. Using qPCR methods, we have found that MEIS1-FOXO1 fusion gene altered the cell cycle related genes expression. Conclusions: Integrating the FOXO1-fusion reports, our data have added more evidence to underline the role of FOXO1 deregulation in the pathogenesis of acute lymphoblastic leukemia. Novel fusion of MEIS1-FOXO1 can potentiate B-ALL via cell cycle entry. Detailed mechanisms involved into the MEIS1-FOXO1 should be further investigated. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

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Two Cases of Pediatric Acute Lymphoblastic Leukemia with t(5;14): a Challenging and Unique Entity

Blood ◽

10.1182/blood.v126.23.4870.4870 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4870-4870

Author(s):

Renee-Pier Fortin-Boudreault ◽

Elaine W. Leung ◽

Mylene Bassal

Keyword(s):

Acute Lymphoblastic Leukemia ◽

Pediatric Patients ◽

Conflicts Of Interest ◽

Residual Disease ◽

Lymphoblastic Leukemia ◽

Behavior Changes ◽

Low Grade ◽

Cell Transplant ◽

St Depression ◽

Pediatric All

Background: Pre-B acute lymphoblastic leukemia (B-ALL) with the t(5;14) translocation occurs in less than 1% of B-ALL diagnoses. This translocation links the IGH on chromosome 14 with IL-3, which results in hypereosinophilia. Interestingly, circulating blasts or cytopenias usually don't accompany the eosinophilia. Patients often present with symptoms related to the eosinophilia, which can be quite morbid, and can delay the diagnosis of ALL. Few pediatric patients with this association have been described in the literature. The presentation and outcome can be quite variable, although it is thought that the prognosis in those patients is worse than standard ALL. Objectives: To review the laboratory and clinical features of pediatric ALL with t(5;14). Methods: Cases of pediatric patients with ALL and t(5;14) diagnosed at the Children's Hospital of Eastern Ontario between 1995 and 2003 were reviewed. Results: We present two 11 year old children, a female and a male, who were diagnosed with B-ALL with t(5;14). The first one presented with a persisting low-grade fever and weight loss as well as asymptomatic lung infiltrates on the chest xray. The second patient presented with chest pain, fever, abdominal pain, as well as a petechial rash and splinter hemorrhages. His EKG showed ST depression, his troponins were elevated and an echocardiogram showed heart dysfunction. He went on and developed behavior changes and cerebral microinfarcts. Common to their presentation was the presence of hyperoesinophilia and absence of circulating blasts. Both had aggressive disease with persistent positive minimal residual disease (MRD) after consolidation and reinduction, which sent them to stem cell transplant. Conclusion: ALL with t(5;14) is a rare entity that usually presents with hypereosinophilia. While eosinophilia can be asymptomatic, it can also be the cause of important morbidity. Diagnosis can be delayed because of the absence of blasts in the peripheral blood and lack of severe cytopenia. Finally, due to its rarity, there is very little information available on how this cytogenic abnormality impacts prognosis, which seems to be worse than ALL without this translocation. Disclosures No relevant conflicts of interest to declare.

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