MiR-128-3p as blood based liquid biopsy biomarker in childhood acute lymphoblastic leukemia.

BACKGROUND: Minimal residual disease (MRD) is one of the most valuable independent prognostic factors in acute lymphoblastic leukemia (ALL). Bone marrow (BM) aspiration, however, is an invasive process. Previous studies have shown that microRNAs (miR) and extracellular vesicle (EV)-related miRs show different expression profiles at the presence of malignant cells compared to healthy controls. In our previous project, we have reported that two miRs previously described to be overexpressed in blasts were significantly decreased over the first week of the therapy of patients with ALL in the platelet free plasma fraction (PFP) of peripheral blood samples (PB). The aim of the current study was to assess the relation between day 15 flow cytometry (FC) MRD and expression of miR-128-3p and miR-222-3p miRs in exosome-enriched fraction (EEF) of PFP to evaluate whether their expression in EEF correlates with day 15 FC MRD more precisely. METHODS: PB was collected from 13 patients diagnosed with pediatric pre-B ALL at 4 time points. Expression of miR-128-3p and miR-222-3p was measured by qPCR in PFP and EEF. RESULTS: Positive correlation was found between changes of miR-128-3p expression in EEF or PFP by day 8 of chemotherapy and day 15 FC MRD (rEEF = 0.99, pEEF = 1.13E-9 and rPFP = 0.99, pPFP = 4.75E-9, respectively). Furthermore, the decrease of miR-128-3p in EEF by day 15 of treatment also showed a positive correlation with day 15 FC MRD (rEEF = 0.96; pEEF = 4.89E-5). CONCLUSION: Our results show that circulating miRs are potential biomarkers of ALL MRD, asmiR-128-3p level both in PFP and EEF predicts day 15 FC MRD. In addition, the assessment of the EEF gave a more promising result.

Two tagging single-nucleotide polymorphisms to capture HLA-DRB1*07:01-DQA1*02:01-DQB1*02:02 haplotype associated with asparaginase hypersensitivity.

AIMS: Asparaginase (ASP) hypersensitivity is a well-known challenge in the treatment of lymphoblastic malignancies. In terms of cost considerations, the cheap native Escherichia coli ASP, the most immunogenic form of this medication, is used in the first line in middle-income countries. Previously, the role of the HLA-DRB1*07:01-DQA1*02:01-DQB1*02:02 haplotype had been established to associate with E. coli ASP hypersensitivity. We investigated a possible cost-effective genetic testing method to identify patients harbouring the risk HLA haplotype in order to pave the way for safer ASP treatment. METHODS: In 241 patients with previously determined HLA-DRB1*07:01-DQA1*02:01-DQB1*02:02 haplotype and known ASP hypersensitivity status, 4 candidate HLA-tagging single-nucleotide polymorphisms (SNP)s were measured, and the performance of the different sets of these tag SNPs was evaluated. RESULTS: We identified a combination of 2 SNPs - rs28383172 and rs7775228 - as a tag for HLA-DRB1*07:01-DQA1*02:01-DQB1*02:02 haplotype with sensitivity and specificity values >95%. In line with previous findings, we found complete concordance between HLA-DRB1*07:01 and rs28383172. With bioinformatics methods, the results were also confirmed in the 1000 Genomes dataset in different ethnic groups. CONCLUSION: Rs28383172 and rs7775228 are suitable for identifying HLA-DRB1*07:01-DQA1*02:01-DQB1*02:02 carriers. Compared to the rest of the population, patients with hypersensitivity-prone genotype would benefit more from the administration of less immunogenic PEGylated ASP before the hypersensitivity evolves, incurring minimal extra cost.

MicroRNA-181a as novel liquid biopsy marker of central nervous system involvement in pediatric acute lymphoblastic leukemia.

BACKGROUND: Refractory central nervous system (CNS) involvement is among the major causes of therapy failure in childhood acute leukemia. Applying contemporary diagnostic methods, CNS disease is often underdiagnosed. To explore more sensitive and less invasive CNS status indicators, we examined microRNA (miR) expressions and extracellular vesicle (EV) characteristics. METHODS: In an acute lymphoblastic leukemia (ALL) discovery cohort, 47 miRs were screened using Custom TaqMan Advanced Low-Density Array gene expression cards. As a validation step, a candidate miR family was further scrutinized with TaqMan Advanced miRNA Assays on serial cerebrospinal fluid (CSF), bone marrow (BM) and peripheral blood samples with different acute leukemia subtypes. Furthermore, small EV-rich fractions were isolated from CSF and the samples were processed for immunoelectron microscopy with anti-CD63 and anti-CD81 antibodies, simultaneously. RESULTS: Regarding the discovery study, principal component analysis identified the role of miR-181-family (miR-181a-5p, miR-181b-5p, miR-181c-5p) in clustering CNS-positive (CNS+) and CNS-negative (CNS‒) CSF samples. We were able to validate miR-181a expression differences: it was about 52 times higher in CSF samples of CNS+ ALL patients compared to CNS‒ cases (n = 8 vs. n = 10, ΔFC = 52.30, p = 1.5E-4), and CNS+ precursor B cell subgroup also had ninefold higher miR-181a levels in their BM (p = 0.04). The sensitivity of CSF miR-181a measurement in ALL highly exceeded those of conventional cytospin in the initial diagnosis of CNS leukemia (90% vs. 54.5%). Pellet resulting from ultracentrifugation of CNS+ CSF samples of ALL patients showed atypical CD63-/CD81- small EVs in high density by immunoelectron microscopy. CONCLUSIONS: After validating in extensive cohorts, quantification of miR-181a or a specific EV subtype might provide novel tools to monitor CNS disease course and further adjust CNS-directed therapy in pediatric ALL.

Circulating microRNAs as minimal residual disease biomarkers in childhood acute lymphoblastic leukemia.

BACKGROUND: Treatment stratification based on bone marrow minimal residual disease (MRD) at set time points has resulted in considerably improved survival in pediatric acute lymphoblastic leukemia (ALL). Treatment response is assessed using bone marrow samples. MicroRNAs (miRs) easily traffic among fluid spaces and are more stable than most other RNA classes. We examined the role of circulating miRs as putative less invasive MRD biomarkers. METHODS: In an exploratory experiment, expression of 46 preselected miRs was studied in platelet-free blood plasma samples of 15 de novo, 5 relapsed ALL patients and 10 controls by Custom TaqMan Array Advanced MicroRNA Card. Based on their high expression in ALL compared to controls, and on the reduction observed along the induction therapy, four miRs were selected for further analyses: miR-128-3p, -181a-5p, -181b-5p and 222-3p. Their expression was measured by qPCR at 4 time points in 27 de novo ALL patients treated in the ALL IC-BFM 2009 study. RESULTS: The expression of all 4 miRs significantly decreased over the first week of therapy (miR-128-3p: log2 fold change - 2.86; adjusted p 3.6 × 10-7; miR-181b-5p: log2 fold change - 1.75; adjusted p 1.48 × 10-2; miR-181a-5p: log2 fold change -1.33; adjusted p 3.12 × 10-2; miR-222-3p: log2 fold change - 1.25; adjusted p 1.66 × 10-2). However, no significant further reduction in miR expression was found after the 8th day of therapy. Measured drop in expression of 2 miRs at day 8 strongly correlated with day 15 bone marrow flow cytometry MRD results (miR-128-3p: Pearson's r = 0.88, adjusted p = 2.71 × 10-4; miR-222-3p: r = 0.81, adjusted p = 2.99 × 10-3). CONCLUSION: In conclusion, these circulating miRs might act as biomarkers of residual leukemia. MiR-128-3p and miR-222-3p in blood predict day 15 flow cytometry MRD results 7 days earlier. Although, their sensitivity falls behind that of bone marrow flow cytometry MRD at day 15.

Possible roles of genetic variations in chemotherapy related cardiotoxicity in pediatric acute lymphoblastic leukemia and osteosarcoma.

BACKGROUND: The treatment of acute lymphoblastic leukemia (ALL) and osteosarcoma (OSC) is very effective: the vast majority of patients recover and survive for decades. However, they still need to face serious adverse effects of chemotherapy. One of these is cardiotoxicity which may lead to progressive heart failure in the long term. Cardiotoxicity is contributed mainly to the use of anthracyclines and might have genetic risk factors. Our goal was to test the association between left ventricular function and genetic variations of candidate genes. METHODS: Echocardiography data from medical records of 622 pediatric ALL and 39 OSC patients were collected from the period 1989-2015. Fractional shortening (FS) and ejection fraction (EF) were determined, 70 single nucleotide polymorphisms (SNPs) in 26 genes were genotyped. Multivariate logistic regression and multi-adjusted general linear model were performed to investigate the influence of genetic polymorphisms on the left ventricular parameters. Bayesian network based Bayesian multilevel analysis of relevance (BN-BMLA) method was applied to test for the potential interaction of the studied cofactors and SNPs. RESULTS: Our results indicate that variations in ABCC2, CYP3A5, NQO1, SLC22A6 and SLC28A3 genes might influence the left ventricular parameters. CYP3A5 rs4646450 TT was 17% among ALL cases with FS lower than 28, and 3% in ALL patients without pathological FS (p = 5.60E-03; OR = 6.94 (1.76-27.39)). SLC28A3 rs7853758 AA was 12% in ALL cases population, while only 1% among controls (p = 6.50E-03; OR = 11.56 (1.98-67.45)). Patients with ABCC2 rs3740066 GG genotype had lower FS during the acute phase of therapy and 5-10 years after treatment (p = 7.38E-03, p = 7.11E-04, respectively). NQO1 rs1043470 rare T allele was associated with lower left ventricular function in the acute phase and 5-10 years after the diagnosis (p = 4.28E-03 and 5.82E-03, respectively), and SLC22A6 gene rs6591722 AA genotype was associated with lower mean FS (p = 1.71E-03), 5-10 years after the diagnosis. CONCLUSIONS: Genetic variants in transporters and metabolic enzymes might modulate the individual risk to cardiac toxicity after chemotherapy.

[New and traditional directions in the biology and management of childhood acute lymphoblastic leukemia]. / Új és hagyományos irányok a gyermekkori akut lymphoblastos leukaemia biológiájában és ellátásában.

Owing to clinical trials and improvement over the past few decades, the majority of children with acute lymphoblastic leukemia (ALL) survive by first-line chemotherapy and combat with the problems of returning to community. However, many patients may have severe acute or late therapeutic side effects, and the survival rate in some groups (e.g., patients with MLL rearrangements, hypodiploidy, IKZF1 mutation or early precursor T cell phenotype) is far behind the average. Innovative strategies in medical attendance provide better clinical outcomes for them: complete gene diagnostics, molecularly targeted anticancer treatment, immuno-oncology and immune cell therapy. The number of genes with identified alterations in leukemic lymphoblasts is over thirty and their pathobiologic role is only partly clear. There are known patient groups where the use of specific drugs is based on gene expression profiling (e.g., tyrosine kinase inhibitors in Philadelphia-like B-cell ALL). The continuous assessment of minimal residual disease became a routine due to the determination of a leukemia-associated immunophenotype by flow cytometry or a sensitive molecular marker by molecular genetics at diagnosis. Epitopes of cluster differentiation antigens on blast surface (primarily CD19, CD20 and CD22 on malignant B cells) can be attacked by monoclonal antibodies. Moreover, antitumor immunity can be strengthened utilizing either cell surface markers (bispecific T cell engagers, chimeric antigen receptor T cell therapy) or tumor-specific immune cells (immune checkpoint inhibitors). This review gives an insight into current knowledge in these innovative therapeutic directions. Orv Hetil. 2018; 159(20): 786-797.

HLA-DRB1*07:01-HLA-DQA1*02:01-HLA-DQB1*02:02 haplotype is associated with a high risk of asparaginase hypersensitivity in acute lymphoblastic leukemia.

Hypersensitivity reactions are the most frequent dose-limiting adverse reactions to Escherichia coli-derived asparaginase in pediatric acute lymphoblastic leukemia (ALL) patients. The aim of the present study was to identify associations between sequence-based Human Leukocyte Antigen Class II region alleles and asparaginase hypersensitivity in a Hungarian ALL population. Four-digit typing of HLA-DRB1 and HLA-DQB1 loci was performed in 359 pediatric ALL patients by using next-generation sequencing method. Based on genotypic data of the two loci, haplotype reconstruction was carried out. In order to investigate the possible role of the HLA-DQ complex, the HLA-DQA1 alleles were also inferred. Multivariate logistic regression analysis and a Bayesian network-based approach were applied to identify relevant genetic risk factors of asparaginase hypersensitivity. Patients with HLA-DRB1*07:01 and HLA-DQB1*02:02 alleles had significantly higher risk of developing asparaginase hypersensitivity compared to non-carriers [P=4.56×10-5; OR=2.86 (1.73-4.75) and P=1.85×10-4; OR=2.99 (1.68-5.31); n=359, respectively]. After haplotype reconstruction, the HLA-DRB1*07:01-HLA-DQB1*02:02 haplotype was associated with an increased risk. After inferring the HLA-DQA1 alleles the HLA-DRB1*07:01-HLA-DQA1*02:01-HLA-DQB1*02:02 haplotype was associated with the highest risk of asparaginase hypersensitivity [P=1.22×10-5; OR=5.00 (2.43-10.29); n=257]. Significantly fewer T-cell ALL patients carried the HLA-DQB1*02:02 allele and the associated haplotype than did pre-B-cell ALL patients (6.5%; vs. 19.2%, respectively; P=0.047). In conclusion, we identified a haplotype in the Human Leukocyte Antigen Class II region associated with a higher risk of asparaginase hypersensitivity. Our results confirm that variations in HLA-D region might influence the development of asparaginase hypersensitivity.

Pharmacogenetic analysis of high-dose methotrexate treatment in children with osteosarcoma.

Inter-individual differences in toxic symptoms and pharmacokinetics of high-dose methotrexate (MTX) treatment may be caused by genetic variants in the MTX pathway. Correlations between polymorphisms and pharmacokinetic parameters and the occurrence of hepato- and myelotoxicity were studied. Single nucleotide polymorphisms (SNPs) of the ABCB1, ABCC1, ABCC2, ABCC3, ABCC10, ABCG2, GGH, SLC19A1 and NR1I2 genes were analyzed in 59 patients with osteosarcoma. Univariate association analysis and Bayesian network-based Bayesian univariate and multilevel analysis of relevance (BN-BMLA) were applied. Rare alleles of 10 SNPs of ABCB1, ABCC2, ABCC3, ABCG2 and NR1I2 genes showed a correlation with the pharmacokinetic values and univariate association analysis. The risk of toxicity was associated with five SNPs in the ABCC2 and NR1I2 genes. Pharmacokinetic parameters were associated with four SNPs of the ABCB1, ABCC3, NR1I2, and GGH genes, and toxicity was shown to be associated with ABCC1 rs246219 and ABCC2 rs717620 using the univariate and BN-BMLA method. BN-BMLA analysis detected relevant effects on the AUC0-48 in the following SNPs: ABCB1 rs928256, ABCC3 rs4793665, and GGH rs3758149. In both univariate and multivariate analyses the SNPs ABCB1 rs928256, ABCC3 rs4793665, GGH rs3758149, and NR1I2 rs3814058 SNPs were relevant. These SNPs should be considered in future dose individualization during treatment.

[Extracellular vesicles and their role in hematological malignancies]. / Extracelluláris vesiculák és hematológiai malignitásokban játszott szerepük.

Extracellular vesicles are produced in all organisms. The most intensively investigated categories of extracellular vesicles include apoptotic bodies, microvesicles and exosomes. Among a very wide range of areas, their role has been confirmed in intercellular communication, immune response and angiogenesis (in both physiological and pathological conditions). Their alterations suggest the potential use of them as biomarkers. In this paper the authors give an insight into the research of extracellular vesicles in general, and then focus on published findings in hematological malignancies. Quantitative and qualitative changes of microvesicles and exosomes may have value in diagnostics, prognostics and minimal residual disease monitoring of hematological malignancies. The function of extracellular vesicles in downregulation of natural killer cells' activity has been demonstrated in acute myeloid leukemia. In chronic lymphocytic leukemia, microvesicles seem to play a role in drug resistance. Orv. Hetil., 2016, 157(35), 1379-1384.

Pharmacogenetics of anthracyclines.

Anthracyclines constitute a fundamental part of the chemotherapy regimens utilized to treat a number of different malignancies both in pediatric and adult patients. These drugs are one of the most efficacious anticancer agents ever invented. On the other hand, anthracyclines are cardiotoxic. Childhood cancer survivors treated with anthracyclines often undergo cardiac complications which are influenced by genetic variations of the patients. The scientific literature comprises numerous investigations in the subject of the pharmacogenetics of anthracyclines. In this review, we provide a comprehensive overview of this research topic. Genetic variants are proposed targets in the personalized treatment in order to individualize dosing and therefore reduce side effects.

Subgroups of Paediatric Acute Lymphoblastic Leukaemia Might Differ Significantly in Genetic Predisposition to Asparaginase Hypersensitivity.

L-asparaginase (ASP) is a key element in the treatment of paediatric acute lymphoblastic leukaemia (ALL). However, hypersensitivity reactions (HSRs) to ASP are major challenges in paediatric patients. Our aim was to investigate genetic variants that may influence the risk to Escherichia coli-derived ASP hypersensitivity. Sample and clinical data collection was carried out from 576 paediatric ALL patients who were treated according to protocols from the Berlin-Frankfurt-Münster Study Group. A total of 20 single nucleotide polymorphisms (SNPs) in GRIA1 and GALNT10 genes were genotyped. Patients with GRIA1 rs4958351 AA/AG genotype showed significantly reduced risk to ASP hypersensitivity compared to patients with GG genotype in the T-cell ALL subgroup (OR = 0.05 (0.01-0.26); p = 4.70E-04), while no such association was found in pre-B-cell ALL. In the medium risk group two SNPs of GRIA1 (rs2055083 and rs707176) were associated significantly with the occurrence of ASP hypersensitivity (OR = 0.21 (0.09-0.53); p = 8.48E-04 and OR = 3.02 (1.36-6.73); p = 6.76E-03, respectively). Evaluating the genders separately, however, the association of rs707176 with ASP HSRs was confined only to females. Our results suggest that genetic variants of GRIA1 might influence the risk to ASP hypersensitivity, but subgroups of patients can differ significantly in this respect.

Roles of genetic polymorphisms in the folate pathway in childhood acute lymphoblastic leukemia evaluated by Bayesian relevance and effect size analysis.

In this study we investigated whether polymorphisms in the folate pathway influenced the risk of childhood acute lymphoblastic leukemia (ALL) or the survival rate of the patients. For this we selected and genotyped 67 SNPs in 15 genes in the folate pathway in 543 children with ALL and 529 controls. The results were evaluated by gender adjusted logistic regression and by the Bayesian network based Bayesian multilevel analysis of relevance (BN-BMLA) methods. Bayesian structure based odds ratios for the relevant variables and interactions were also calculated. Altogether 9 SNPs in 8 genes were associated with altered susceptibility to ALL. After correction for multiple testing, two associations remained significant. The genotype distribution of the MTHFD1 rs1076991 differed significantly between the ALL and control population. Analyzing the subtypes of the disease the GG genotype increased only the risk of B-cell ALL (p = 3.52×10(-4); OR = 2.00). The GG genotype of the rs3776455 SNP in the MTRR gene was associated with a significantly reduced risk to ALL (p = 1.21×10(-3); OR = 0.55), which resulted mainly from the reduced risk to B-cell and hyperdiploid-ALL. The TC genotype of the rs9909104 SNP in the SHMT1 gene was associated with a lower survival rate comparing it to the TT genotype (80.2% vs. 88.8%; p = 0.01). The BN-BMLA confirmed the main findings of the frequentist-based analysis and showed structural interactional maps and the probabilities of the different structural association types of the relevant SNPs especially in the hyperdiploid-ALL, involving additional SNPs in genes like TYMS, DHFR and GGH. We also investigated the statistical interactions and redundancies using structural model properties. These results gave further evidence that polymorphisms in the folate pathway could influence the ALL risk and the effectiveness of the therapy. It was also shown that in gene association studies the BN-BMLA could be a useful supplementary to the traditional frequentist-based statistical method.

Candidate gene association study in pediatric acute lymphoblastic leukemia evaluated by Bayesian network based Bayesian multilevel analysis of relevance.

BACKGROUND: We carried out a candidate gene association study in pediatric acute lymphoblastic leukemia (ALL) to identify possible genetic risk factors in a Hungarian population. METHODS: The results were evaluated with traditional statistical methods and with our newly developed Bayesian network based Bayesian multilevel analysis of relevance (BN-BMLA) method. We collected genomic DNA and clinical data from 543 children, who underwent chemotherapy due to ALL, and 529 healthy controls. Altogether 66 single nucleotide polymorphisms (SNPs) in 19 candidate genes were genotyped. RESULTS: With logistic regression, we identified 6 SNPs in the ARID5B and IKZF1 genes associated with increased risk to B-cell ALL, and two SNPs in the STAT3 gene, which decreased the risk to hyperdiploid ALL. Because the associated SNPs were in linkage in each gene, these associations corresponded to one signal per gene. The odds ratio (OR) associated with the tag SNPs were: OR = 1.69, P = 2.22x10(-7) for rs4132601 (IKZF1), OR = 1.53, P = 1.95x10(-5) for rs10821936 (ARID5B) and OR = 0.64, P = 2.32x10(-4) for rs12949918 (STAT3). With the BN-BMLA we confirmed the findings of the frequentist-based method and received additional information about the nature of the relations between the SNPs and the disease. E.g. the rs10821936 in ARID5B and rs17405722 in STAT3 showed a weak interaction, and in case of T-cell lineage sample group, the gender showed a weak interaction with three SNPs in three genes. In the hyperdiploid patient group the BN-BMLA detected a strong interaction among SNPs in the NOTCH1, STAT1, STAT3 and BCL2 genes. Evaluating the survival rate of the patients with ALL, the BN-BMLA showed that besides risk groups and subtypes, genetic variations in the BAX and CEBPA genes might also influence the probability of survival of the patients. CONCLUSIONS: In the present study we confirmed the roles of genetic variations in ARID5B and IKZF1 in the susceptibility to B-cell ALL. With the newly developed BN-BMLA method several gene-gene, gene-phenotype and phenotype-phenotype connections were revealed. We showed several advantageous features of the new method, and suggested that in gene association studies the BN-BMLA might be a useful supplementary to the traditional frequentist-based statistical method.