Risk Of Acute Lymphoblastic Leukemia Research Articles

Association of Chromosome Arm 9p Abnormalities With Adverse Risk in Childhood Acute Lymphoblastic Leukemia: A Report From the Children's Cancer Group

AbstractCytogenetic abnormalities of chromosome arm 9p occur frequently in children with acute lymphoblastic leukemia (ALL). We analyzed 201 such cases (11%) in 1,839 children with newly diagnosed ALL treated between 1989 and 1995 on risk-adjusted protocols of the Children's Cancer Group (CCG). The majority of patients (131; 65%) with a 9p abnormality were classified as higher risk. Nearly all patients had complex karyotypes; most cases had deletions of 9p, add/der(9p), a dicentric involving chromosome arm 9p, and/or balanced translocations and inversions involving 9p. Event-free survival (EFS) estimates at 6 years for patients with and without a 9p aberration were 61% (standard deviation [SD] = 5%) and 76% (SD = 2%;P < .0001). In addition, patients with a 9p abnormality had an increased cumulative incidence of both marrow (P = .04) and central nervous system (P = .0001) relapses. Overall survival also was significantly worse for patients with an abnormal 9p (P < .0001). These effects were most pronounced in standard-risk patients (age 1 to 9 years with white blood cell count <50,000/μL): 6-year EFS of 61% (SD = 9%) versus 80% (SD = 2%; P < .0001). Also, a 9p aberration was an adverse risk factor for B-lineage, but not T-lineage patients. The effect of 9p status on EFS was attenuated, but maintained in a multivariate analysis of EFS after adjustment for Philadelphia chromosome status, age, white blood cell (WBC) count, sex, race, and ploidy group (P= .01). Thus, abnormalities of chromosome arm 9p identify a subgroup of standard-risk patients with increased risk of treatment failure.

Hypodiploidy With Less Than 45 Chromosomes Confers Adverse Risk in Childhood Acute Lymphoblastic Leukemia: A Report From the Children's Cancer Group

AbstractWe have determined the prognostic significance of hypodiploidy (<46 chromosomes) in a large cohort of children with acute lymphoblastic leukemia (ALL) treated by the Children's Cancer Group. Among 1,880 patients, 110 (5.8%) had hypodiploid karyotypes: 87 had 45 chromosomes, 15 had 33 to 44 chromosomes, none had 29 to 32 chromosomes, and 8 had 24 to 28 chromosomes (near-haploidy). Six-year event-free survival (EFS) estimates for patients with 45 chromosomes, 33 to 44 chromosomes, or 24 to 28 chromosomes were 65% (standard deviation [SD], 8%), 40% (SD, 18%), and 25% (SD, 22%), respectively (log rank, P = .002; test for trend, P = .0009). The combined hypodiploid group had worse outcome than nonhypodiploid patients, with 6-year EFS of 58% (SD, 7%) and 76% (SD, 2%), respectively (P < .0001). EFS for the subgroup with 45 chromosomes was similar to that of patients with pseudodiploidy (P = .43) or 47 to 50 chromosomes (P = .76). None of the patients with 24 to 28 chromosomes had a t(4;11), a t(9;22), or a t(1;19), and most received highly intensive therapy. The adverse risk associated with 33 to 44 and 24 to 28 chromosomes remained significant in multivariate analyses adjusted for important risk factors including age, white blood cell count, and Philadelphia chromosome status. Thus, hypodiploidy with less than 45 chromosomes, particularly 24 to 28 chromosomes, is a significant adverse risk factor despite treatment with contemporary intensive therapies.

DNA Methylation-Mediated Silencing of Mir-204 Enhances the Occurrence of T-Cell Acute Lymphoblastic Leukemia By Upregulating MMP-2 and MMP-9 through the NF-Κb Signaling Pathway

Background : MicroRNAs (miR) are non-coding RNAs that play a role in regulation multiple functions in different cell types. Previous studies have shown that miR-204 is downregulated in T-ALL. We previously reported that matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) gene polymorphisms may be associated with the risk of T-cell acute lymphoblastic leukemia (T-ALL). The present study aims to decipher the role of miR-204 and MMP-2/MMP-9 in T-ALL occurrence to guide the diagnosis and treatment of T-ALL in the clinics. Methods: Expression of miR-204 was determined in the bone marrow and peripheral blood samples from 70 T-ALL patients and 70 healthy volunteers by real-time quantitative PCR (RT-qPCR). Bisulfite sequencing PCR (BSP) was used to detect the DNA methylation levels of the miR-204 promoter region in T-ALL patients and T-ALL cell lines.The effect of miR-204 on cell proliferation was evaluated with the cell counting kit-8 solution (CCK-8) assay and by Hoechst and PI double staining. The binding site of miR-204 on IRAK1 was predicted by the Primer Premier 5.0 and the defined binding sequences were used to construct luciferase-tag plasmids. The regulation of IRAK1 expression by miR-204 was evaluated by RT-qPCR and Western blot analysis. With the purpose to confirm the role of MMP-2 and MMP-9 in the occurrence of T-ALL, we investigated the effect of related proteins on T-ALL cells using Western blot. To determine that miR-204 affects the occurrence of T-ALL disease by regulating the NF-KB signaling pathway, RT-qPCR and Western Blot were used for verification. Results: DNA methylation directly affects the miR-204 expression in the promoter region when T-ALL developed. Moreover, overexpression of miR-204 inhibited the proliferation and enhanced the apoptosis of T-ALL cells. Notably, overexpression of miR-204 inhibited IRAK1, which in turn inhibited the proliferation and enhanced the apoptosis of T-ALL cells. Furthermore, IRAK1 enhanced the expression of MMP-2 and MMP-9 through phosphorylation of of p65 NF-κB, and miR-204 modulated MMP-2 and MMP-9 expression through the IRAK1/NF-κB signaling pathway. Conclusion s : Our results demonstrate that in T-ALL cells, DNA methylation-mediated silencing of miR-204 regulates the expression of MMP-2 and MMP-9 through increased transcription of IRAK1, and activation of the NF-κB signaling pathway. These data provide a potential mechanism for the role of MMP-2 and MMP-9 in the occurrence of T-ALL. Further studies will be needed to demonstrate whether demethylation of miR-204 may be a promising treatment for T-ALL. Disclosures No relevant conflicts of interest to declare.

Pre-Transplant Clonal Mosaicism Is Associated with Increased Relapse and Lower Survival in Acute Lymphoblastic Leukemia Patients Undergoing Allogeneic Hematopoietic Cell Transplant

Clonal mosaicism, detectable in peripheral blood, can be an important predictor of developing a hematological malignancy. We sought to determine if mosaic events, in addition to clinical and demographic variables, contributed independent information about acute lymphoblastic leukemia (ALL) patient survival and risk of relapse after allogeneic hematopoietic cell transplant (HCT). HumanOmniExpress-12v1_A BeadChip SNP array data were used to detect mosaicisms &amp;gt;=2Mb based on the log2 relative probe intensity ratio (LRR) and B allele frequency (BAF) for each SNP measured in 773 ALL patients from DISCOVeRY-BMT cohorts. DNA was extracted from recipient peripheral blood samples taken immediately prior to start of conditioning before allogeneic HCT for ALL (2000-2011). Mosaic events include copy-number gain (LRR &amp;gt;0), loss (LRR &amp;lt;0), or copy-neutral loss of heterozygosity (CNLOH), defined as a deviation from BAF heterozygosity without LRR changes. The impact of mosaicism on overall survival (OS) probability and cumulative incidence of relapse at 1-year post-HCT were calculated using the Kaplan-Meier estimator and cumulative incidence functions, respectively. The association of clonal mosaicism with OS was evaluated with multivariable Cox proportional hazard models. For disease relapse, competing risk models were used with transplant related mortality (TRM) treated as a competing event. Stratified survival analyses were performed by cytogenetic status at diagnosis. Statistical analyses were conducted using R 3.6.1. Thirty-four patients (4.4%) had 1 or more mosaicisms (82 total detected) with almost half having advanced disease (Table 1). The median proportion of affected cells was 61% (interquartile range = 39 - 93%). Copy-number losses on chromosomes 7 (13.4%) and 9 (8.54%) and 17 (6.10%) were the most frequently detected events (Figure 1). OS at 1-year post HCT in patients with and without a mosaic event was 26.5% and 60.1%, respectively, (P=8.2×10-8, Figure 2A) and normal cytogenetic patients with mosaicism had significantly lower survival compared to all other patients (OSnormal/mosaic+= 8.3% vs. OS= 60.6%, P=3.0×10-10, Figure 2B-C). ALL patients with a mosaic event also had an increased risk of disease relapse overall (Relapsemosaic+= 50% vs. Relapsemosaic-=26%, P=0.00067) and when stratified by cytogenetic abnormalities (P=0.015) and normal cytogenetics (P=0.041) (Figure 2D-F). Multivariable models of OS and relapse included age, race/ethnicity, complete remission or advanced disease status (Figure 3). Patients with a mosaic event had ~2.5 fold increase risk of death (P=2.5×10-5), independent from cytogenetics (P=8.6×10-5, Figure 3). OS associations are likely driven by the 2.8 fold increase risk of relapse (P= 5.9×10-5) which remains highly significant when stratified by cytogenetics (Figure 3). Almost half of the copy-number losses included well-known regions on chromosomes 7, 9 and 17 (Figure 1). Deletions of 7p have been shown to correlate with lower event-free survival in ALL pediatric patients. Our findings suggest mosaic loss of 7p might be an important indicator of poor OS across the lifespan, with 5/6 patients with 7p losses aged &amp;gt;18 years. Higher mortality was also associated with the loss of the chr9p21.3 locus, seen in all patients (N=5) with chromosome 9p losses. This region harbors tumor suppressor CDKN2A; inactivation of CDKN2A can lead to poor survival in both children and adults with ALL. Lastly, we found that all patients (N=4) with copy-number loss of 17p13.1, which contains tumor suppressor TP53 died within 1-year post-HCT. We identified detectable mosaicism prior to transplant in 4.4% of patients and showed that mosaicism was associated with lower survival and higher disease relapse at 1-year post-HCT. While mosaicism is more common in patients with advanced disease stage, mosaic events are an independent contributor to lower survival and higher relapse in the first year after transplant. This is the first study to show that mosaic events detectable in pre-transplant peripheral blood from ALL patients are correlated with poor survival. Future studies replicating these associations in different ethnicities and age groups and evaluating specific chromosomal regions could be informative in classifying patient risk post-HCT attributable to mosaic events. Disclosures McCarthy: Karyopharm: Consultancy, Honoraria; Magenta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Genentech: Consultancy, Honoraria; Starton: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board; Juno Therapeutics, a Bristol-Myers Squibb Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Advisory Board , Research Funding is to Roswell Park, Research Funding. Pasquini:Bristol Myers Squibb: Consultancy; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Other; Novartis: Research Funding; Kite: Research Funding. Lee:Pfizer: Consultancy, Research Funding; Novartis: Research Funding; Takeda: Research Funding; Amgen: Research Funding; Kadmon: Research Funding; Incyte: Consultancy, Research Funding; AstraZeneca: Research Funding; Syndax: Research Funding.

Novel Target Genes and Epigenetic Pathways Involved in High Risk Acute Lymphoblastic Leukemia

Acute leukemias (AL) is a major cause of cancer death in young age. Extensive research is being conducted to identify novel and innovative approaches for leukemia treatment. Transcriptomic and epigenetic studies might help to discover potential targets, paving the way for molecular-targeted therapies. We analyzed a cohort of 34 AL at diagnosis: 10 pediatric Acute Lymphoblastic Leukemias (8 B-cell, 1 T-cell and 1 bi-phenotypic ALL), 4 young adult ALL (2 B-cell and 2 T-cell phenotype), and 20 pediatric Acute Myeloid Leukemias (AML: 3 M1, 4 M2, 1 M3, 5 M4, 7 M5) with an average blasts population higher than 80% (85+/-11% in ALL; 83+/-13% in AML). Six out of 14 ALL, and 12 out of 20 AML fell under "high risk" category according to clinical standard risk stratification algorithms. On all patients we performed mRNA sequencing (20-million-reads on Illumina Hiseq 4000). Analyses were performed adjusting &amp;lt;0.05 significant p values for multiple testing with the FDR Benjamini-Hochberg procedure. The expression of a set of 800 microRNAs (miRNAs) was evaluated by means of Nanostring miRNA panel. Expression signatures and associations among the different risk groups were calculated with t-tests and linear regression analyses. Applying stringent FDR statistical measurement, we discovered 3 genes that significantly differentiate the transcriptomic profile of high vsintermediate/standard-risk ALL in mRNAseq. The expression of PGR3 (p53 Responsive Gene) and long-non-coding RNAs (lncRNAs) ENSG00000228737 and ENSG00000253174 were respectively 45.5, 4.2 and 3.9 time downregulated in high-risk ALL. To explore more deeply the apoptosis pathway in ALL, we measured Tp53 expression and found it significantly downregulated in the high-risk vsintermediate-standard-risk ALL (p=&amp;lt;0.05, not adj for FDR). Consistently also the linear regression between PGR3 and p53 was significant (p&amp;lt;0.01). No differences in the expression of these genes were detected in AML samples. Tp53 dysregulation is a known hallmark for tumor progression; Tp53 mutations - ranging from 1-2% to 10% in pediatric and adult ALs - correlate with worse prognosis. However, in our cohorts, this gene signature was found significant only in high-risk ALL, homogeneously distinguishing them from intermediate/standard-risk ALL. Transcriptome clinical variant analyses excluded pathogenetic known variants that could explain such marked difference. Also, it is unlikely that somatic genetic mutations acquired by the tumor would explain such a homogeneous behavior of high-risk ALL. Thus, we analyzed the p53 regulatory pathway. Interestingly we found that miRNAs known to be involved in p53 control were significantly upregulated in high-risk vs intermediate-standard-risk ALL (p&amp;lt;0.0404) (Fig.1f-g), suggesting that an epigenetic control is active in high-risk ALL. Also, 2 lncRNAs were highly downregulated in high-risk ALL. Their function is still unknown, but interestingly, one of them ENSG00000253174correlates with GINS4, part of a protein complex implicated in DNA replication and cell proliferation and known to be upregulated in multiple neoplasia like gastric, colon and lung cancer. In our cohorts we found GINS4 significantly downregulated in high-risk vs standard/intermediate-risk ALL (Fig.1d). GINS4 axis is still unknown in AL. We found PRG3 and Tp53 significantly downregulated in high-risk ALL, with PRG3 expression 45 times lower than intermediate/low-risks ALL. Deeper analyses pointed out to an apoptosis control program not generated by a somatic mutation in the tumor, nor a germline clinical patient variant, but by an epigenetic mechanism. We are currently validating these data in a larger cohort, adding also methylome analyses. It will be interesting also to explore the function of the lncRNAs markedly downregulated in our cohort, whose functions are still unknown or partially known. Because of the small numerosity of the ALL high-risk cohort, we were not able to dissect high-risk young adults (4/6) from pediatric ALL (2/6). Although the homogeneity of data suggests a shared apoptosis control mechanism, it will be worthy to explore in a larger cohort whether the general worse prognosis of young adults/adults vs pediatric ALL is at least partially explained by this mechanism. Disclosures No relevant conflicts of interest to declare.

Genetic variation in the body mass index of adult survivors of childhood acute lymphoblastic leukemia: A report from the Childhood Cancer Survivor Study and the St. Jude Lifetime Cohort.

Treatment characteristics such as cranial radiation therapy (CRT) do not fully explain adiposity risk in childhood acute lymphoblastic leukemia (ALL) survivors. This study was aimed at characterizing genetic variation related to adult body mass index (BMI) among survivors of childhood ALL. Genetic associations of BMI among 1458 adult survivors of childhood ALL (median time from diagnosis, 20 years) were analyzed by multiple approaches. A 2-stage genome-wide association study in the Childhood Cancer Survivor Study (CCSS) and the St. Jude Lifetime Cohort Study (SJLIFE) was performed. BMI was a highly polygenic trait in the general population. Within the known loci, the BMI percent variance explained was estimated, and additive interactions (chi-square test) with CRT in the CCSS were evaluated. The role of DNA methylation in CRT interaction was further evaluated in a subsample of ALL survivors. In a meta-analysis of the CCSS and SJLIFE, 2 novel loci associated with adult BMI among survivors of childhood ALL (LINC00856 rs575792008 and EMR1 rs62123082; PMeta < 5E-8) were identified. It was estimated that the more than 700 known loci explained 6.2% of the variation in adult BMI in childhood ALL survivors. Within the known loci, significant main effects for 23 loci and statistical interactions with CRT at 9 loci (P < 7.0E-5) were further identified. At 2 CRT-interacting loci, DNA methylation patterns may have differed by age. Adult survivors of childhood ALL have genetic heritability for BMI similar to that observed in the general population. This study provides evidence that treatment with CRT can modify the effect of genetic variants on adult BMI in childhood ALL survivors.

Extremely Low-Frequency Magnetic Fields and the Risk of Childhood B-Lineage Acute Lymphoblastic Leukemia in a City With High Incidence of Leukemia and Elevated Exposure to ELF Magnetic Fields.

It is important to study the relationship between extremely low-frequency magnetic fields (ELF-MFs) and childhood leukemia, particularly in locations with a high incidence of this neoplasm in children and an elevated exposure to ELF-MF, such as Mexico City. The aim was to investigate the association between ELF-MF exposure and the risk of B-lineage acute lymphoblastic leukemia (B-ALL). A case-control study was conducted in Mexico City during the period from 2010 to 2011. Residential 24-h ELF-MF measurements were obtained for 290 incident B-ALL patients and 407 controls, aged less than 16 years. Controls were frequency-matched by sex, age (±18 months), and health institution. The adjusted odds ratios (aOR) and 95% confidence intervals (CIs) were calculated. ELF-MF exposure at <0.2 μT was used to define the reference group. ELF-MF exposure at ≥0.3 μT was observed in 11.3% of the controls. Different ELF-MF intensity cutoff values were used to define the highest exposure category; the highest exposure category for each cutoff value was associated with an increased risk of B-ALL compared with the corresponding lower exposure categories. The aORs were as follows: ≥0.2 μT = 1.26 (95% CI: 0.84-1.89); ≥0.3 μT = 1.53 (95% CI: 0.95-2.48); ≥0.4 μT = 1.87 (95% CI: 1.04-3.35); ≥0.5 μT = 1.80 (95% CI 0.95-3.44); ≥0.6 μT = 2.32 (95% CI: 1.10-4.93). ELF-MF exposure as a continuous variable (per 0.2 μT intervals) was associated with B-ALL risk (aOR = 1.06; 95% CI: 1.01-1.12). In the present study, the proportion of children exposed to ≥0.3 μT is among the highest reported worldwide. Additionally, an ELF-MF exposure ≥0.4 μT may be associated with the risk of B-ALL. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

Genotype-Environment Interaction Analysis of NQO1, CYP2E1, and NAT2 Polymorphisms and the Risk of Childhood Acute Lymphoblastic Leukemia: A Report From the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia.

Background: Acute lymphoblastic leukemia (ALL) is the main type of cancer in children. In Mexico and other Hispanic populations, the incidence of this neoplasm is one of the highest reported worldwide. Functional polymorphisms of various enzymes involved in the metabolism of xenobiotics have been associated with an increased risk of developing ALL, and the risk is different by ethnicity. The aims of the present study were to identify whether NQO1, CYP2E1, and NAT2 polymorphisms or some genotype-environmental interactions were associated with ALL risk in Mexican children.Methods: We conducted a case-control study including 478 pediatric patients diagnosed with ALL and 284 controls (children without leukemia). Ancestry composition of a subset of cases and controls was assessed using 32 ancestry informative markers. Genetic-environmental interactions for the exposure to hydrocarbons were assessed by logistic regression analysis.Results: The polymorphisms rs1801280 (OR 1.54, 95% CI 1.21–1.93), rs1799929 (OR 1.96, 95% CI 1.55–2.49), and rs1208 (OR 1.44, 95% CI 1.14–1.81) were found to increase the risk of ALL; being the risks higher under a recessive model (OR 2.20, 95% CI 1.30–1.71, OR 3.87, 95% CI 2.20–6.80, and OR 2.26, 95% CI 1.32–3.87, respectively). Gene-environment interaction analysis showed that NAT2 rs1799929 TT genotype confers high risk to ALL under exposure to fertilizers, insecticides, hydrocarbon derivatives, and parental tobacco smoking. No associations among NQO1, CYP2E1, and ALL were observed.Conclusion: Our study provides evidence for the association between NAT2 polymorphisms/gene-environment interactions, and the risk of childhood ALL in Mexican children.

Association of GATA3 Polymorphisms With Minimal Residual Disease and Relapse Risk in Childhood Acute Lymphoblastic Leukemia.

Minimal residual disease (MRD) after induction therapy is one of the strongest prognostic factors in childhood acute lymphoblastic leukemia (ALL), and MRD-directed treatment intensification improves survival. Little is known about the effects of inherited genetic variants on interpatient variability in MRD. A genome-wide association study was performed on 2597 children on the Children's Oncology Group AALL0232 trial for high-risk B-cell ALL. Association between genotype and end-of-induction MRD levels was evaluated for 863370 single nucleotide polymorphisms (SNPs), adjusting for genetic ancestry and treatment strata. Top variants were further evaluated in a validation cohort of 491 patients from the Children's Oncology Group P9905 and 6 ALL trials. The independent prognostic value of single nucleotide polymorphisms was determined in multivariable analyses. All statistical tests were 2-sided. In the discovery genome-wide association study, we identified a genome-wide significant association at the GATA3 locus (rs3824662, odds ratio [OR] = 1.58, 95% confidence interval [CI] = 1.35 to 1.84; P = 1.15 × 10-8 as a dichotomous variable). This association was replicated in the validation cohort (P = .003, MRD as a dichotomous variable). The rs3824662 risk allele independently predicted ALL relapse after adjusting for age, white blood cell count, and leukemia DNA index (P = .04 and .007 in the discovery and validation cohort, respectively) and remained prognostic when the analyses were restricted to MRD-negative patients (P = .04 and .03 for the discovery and validation cohorts, respectively). Inherited GATA3 variant rs3824662 strongly influences ALL response to remission induction therapy and is associated with relapse. This work highlights the potential utility of germline variants in upfront risk stratification in ALL.

Risk-associated alterations in marrow T cells in pediatric leukemia.

Current management of childhood leukemia is tailored based on disease risk determined by clinical features at presentation. Whether properties of the host immune response impact disease risk and outcome is not known. Here, we combine mass cytometry, single cell genomics, and functional studies to characterize the BM immune environment in children with B cell acute lymphoblastic leukemia and acute myelogenous leukemia at presentation. T cells in leukemia marrow demonstrate evidence of chronic immune activation and exhaustion/dysfunction, with attrition of naive T cells and TCF1+ stem-like memory T cells and accumulation of terminally differentiated effector T cells. Marrow-infiltrating NK cells also exhibit evidence of dysfunction, particularly in myeloid leukemia. Properties of immune cells identified distinct immune phenotype–based clusters correlating with disease risk in acute lymphoblastic leukemia. High-risk immune signatures were associated with expression of stem-like genes on tumor cells. These data provide a comprehensive assessment of the immune landscape of childhood leukemias and identify targets potentially amenable to therapeutic intervention. These studies also suggest that properties of the host response with depletion of naive T cells and accumulation of terminal-effector T cells may contribute to the biologic basis of disease risk. Properties of immune microenvironment identified here may also impact optimal application of immune therapies, including T cell–redirection approaches in childhood leukemia.

Abstract 1173: Disparity in pediatric B-cell acute lymphoblastic leukemia relapse between Hispanics and Non-Hispanic Whites: A potential role of miR-3158-3p

Abstract Background: Hispanics (HSP) have a higher risk of pediatric acute lymphoblastic leukemia (ALL) relapse compared to Non-Hispanic Whites (NHW). Although previous studies suggest a biological contribution to the ethnic disparity, the biological mechanism is not fully elucidated. In this study, we evaluated the potential role of miRNAs in the disparity of pediatric B-ALL early relapse in a two-stage pilot study. Methods: We first performed a discovery phase on 14 HSP (7 relapse and 7 remission) and 14 NHW (7 relapse and 7 remission) preselected initial diagnostic B-ALL, minimal residual disease negative specimens without adverse cytogenetic features. Global miRNA expression profiles were compared between remission and relapse patients in the combined sample (14 relapse vs 14 remission) and between ethnic groups (14 HSP vs 14 NHW). We then selected candidate miRNAs that were differentially expressed between combined remission and relapse samples as well as between HSP and NHW for validation. Validation and expression of candidate miRNAs within each ethnic group were performed on a publicly available data from the Therapeutically Applicable Research To Generate Effective Treatments (TARGET) program using 22 HSP (12 relapse and 10 remission) and 71 NHW (39 relapse and 32 remission) that had miRNA-seq, ethnicity and relapse data available. Results: In the discovery phase, miR-3158-3p, miR-378j and miR-4642 were differentially expressed between remission and relapse samples as well as between HSP and NHW. The expressions of miR-3158-3p (fold change (FC)=0.87, p=0.046), and miR-378j (FC=0.85, p=0.043) were decreased in relapse compared to remission patients, but the decrease was more prominent in NHW (miR-3158-3p: FC=0.83, p=0.047 and miR-378j: FC=0.81, p=0.077) than HSP (miR-3158-3p: FC=0.91, p=0.35 and miR-378j: FC=0.89, p=0.18). In contrast, the expression of miR-4642 was elevated (FC=1.29, p=0.011) in relapse compared to remission patients, but the elevation was more prominent in HSP (FC=1.58, p=0.005) than NHW (FC=1.04, p=0.51). In addition, miR-3158-3p (FC=0.87, p=0.040) and miR-4642 (FC=0.81, p=0.047) were under-expressed in NHW compared to HSP, while miR-378j (FC=1.23, p=0.013) was overexpressed in NHW compared to HSP. The under-expression of miR-3158-3p in relapse compared to remission samples (NHW: FC=0.75, p=0.007; overall: FC=0.86, p=0.07) was validated in the independent TARGET dataset. In silico analysis using DIANA microT predicted that miR-3158-3p targeted three genes, SMAD4, SHC and NFKB1, that are implicated in leukemia. Conclusion: This study adds to the accumulating evidence that miRNAs have critical roles in pediatric B-ALL relapse and provides preliminary evidence, for the first time, that miRNA expression may contribute to the ethnic disparity in pediatric B-ALL relapse. However, these findings need to be validated in a larger cohort and the biological role of the miRNAs in the disparity of pediatric B-ALL relapse needs to be elucidated. Citation Format: Ernest K. Amankwah, Anders Berglund, Karen Rabin, Patrick A. Brown, Jong Y. Park. Disparity in pediatric B-cell acute lymphoblastic leukemia relapse between Hispanics and Non-Hispanic Whites: A potential role of miR-3158-3p [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1173.

IKZF1 rs4132601 and rs11978267 Gene Polymorphisms and Acute Lymphoblastic Leukemia: Relation to Disease Susceptibility and Outcome.

(IKZF1) rs4132601 and rs11978267 are common gene polymorphisms and have been associated with the risk of acute lymphoblastic leukemia. However, these associations are less evident in races and/or ethnicities other than European and Hispanic. Therefore, we investigated the association between these single-nucleotide polymorphisms and acute lymphoblastic leukemia susceptibility and disease outcome. Real-time polymerase chain reaction typing was performed for IKZF1 rs4132601 and rs11978267 for 128 pediatric acute lymphoblastic leukemia (pALL), 45 adult acute lymphoblastic leukemia (aALL), and 436 healthy controls. The G allele-containing and G-containing genotypes (GG+GT) of rs4132601 were significantly higher in pALL (P=0.003, odds ratio [OR]=1.65, 0.009, OR=1.42, respectively) and aALL (P=0.016, OR=1.81 and 0.011, OR=1.61, respectively). However, the GG haplotype was associated with the risk of pALL (P=0.044), the GA haplotype was associated with the risk of aALL (P=0.007). In aALL, the GG genotype of rs4132601 was associated with absence of remission and poor overall survival (P=0.003 and 0.041, respectively). The IKZF1 rs4132601 single-nucleotide polymorphism can be considered a susceptibility risk factor for the development of pALL and aALL in the studied cohort of Egyptian patients. The GG genotype of IKZF1 rs4132601 may be a risk factor for poor outcome in aALL patients.

The impact of donor type on the outcome of pediatric patients with very high risk acute lymphoblastic leukemia. A study of the ALL SCT 2003 BFM-SG and 2007-BFM-International SG

Allogeneic HSCT represents the only potentially curative treatment for very high risk (VHR) ALL. Two consecutive international prospective studies, ALL-SCT-(I)BFM 2003 and 2007 were conducted in 1150 pediatric patients. 569 presented with VHR disease leading to any kind of HSCT. All patients >2 year old were transplanted after TBI-based MAC. The median follow-up was 5 years. 463 patients were transplanted from matched donor (MD) and 106 from mismatched donor (MMD). 214 were in CR1. Stem cell source was unmanipulated BM for 330 patients, unmanipulated PBSC for 135, ex vivo T-cell depleted PBSC for 62 and cord-blood for 26. There were more advanced disease, more ex vivo T-cell depletion, and more chemotherapy based conditioning regimen for patients transplanted from MMD as compared to those transplanted from MSD or MD. Median follow up (reversed Kaplan Meier estimator) was 4.99 years, median follow up of survivals was 4.88, range (0.01–11.72) years. The 4-year CI of extensive cGvHD was 13 ± 2% and 17 ± 4% (p = NS) for the patients transplanted from MD and MMD, respectively. 4-year EFS was statistically better for patients transplanted from MD (60 ± 2% vs. 42 ± 5%, p < 0.001) for the whole cohort. This difference does not exist if considering separately patients treated in the most recent study. There was no difference in 4-year CI of relapse. The 4-year NRM was lower for patients transplanted from MD (9 ± 1% vs. 23 ± 4%, p < 0.001). In multivariate analysis, donor-type appears as a negative risk-factor for OS, EFS, and NRM. This paper demonstrates the impact of donor type on overall results of allogeneic stem cell transplantation for very-high risk pediatric acute lymphoblastic leukemia with worse results when using MMD stem cell source.

Leveraging Genome and Phenome-Wide Association Studies to Investigate Genetic Risk of Acute Lymphoblastic Leukemia.

Genome-wide association studies (GWAS) of childhood cancers remain limited, highlighting the need for novel analytic strategies. We describe a hybrid GWAS and phenome-wide association study (PheWAS) approach to uncover genotype-phenotype relationships and candidate risk loci, applying it to acute lymphoblastic leukemia (ALL). PheWAS was performed for 12 ALL SNPs identified by prior GWAS and two control SNP-sets using UK Biobank data. PheWAS-traits significantly associated with ALL SNPs compared with control SNPs were assessed for association with ALL risk (959 cases, 2,624 controls) using polygenic score and Mendelian randomization analyses. Trait-associated SNPs were tested for association with ALL risk in single-SNP analyses, with replication in an independent case-control dataset (1,618 cases, 9,409 controls). Platelet count was the trait most enriched for association with known ALL risk loci. A polygenic score for platelet count (223 SNPs) was not associated with ALL risk (P = 0.82) and Mendelian randomization did not suggest a causal relationship. However, twelve platelet count-associated SNPs were nominally associated with ALL risk in COG data and three were replicated in UK data (rs10058074, rs210142, rs2836441). In our hybrid GWAS-PheWAS approach, we identify pleiotropic genetic variation contributing to ALL risk and platelet count. Three SNPs known to influence platelet count were reproducibly associated with ALL risk, implicating genomic regions containing IRF1, proapoptotic protein BAK1, and ERG in platelet production and leukemogenesis. Incorporating PheWAS data into association studies can leverage genetic pleiotropy to identify cancer risk loci, highlighting the utility of our novel approach.

Body mass index associated with childhood and adolescent high-risk B-cell acute lymphoblastic leukemia risk: A Children's Oncology Group report.

BackgroundObesity is a risk factor for many adulthood cancers, but its role in childhood, adolescent, and young adult (AYA) cancer is unknown. Childhood and AYA acute lymphoblastic leukemia (ALL) incidence and obesity prevalence have shown concurrent increases. We sought to identify whether obesity may be a risk factor for childhood and AYA ALL.MethodsCharacteristics from individuals with ALL, aged 2‐30 years, diagnosed 2004‐2017 and treated on Children's Oncology Group (COG) protocols with available pre‐treatment anthropometric data (N = 4726) were compared to National Health and Nutrition Examination Survey controls (COG AALL17D2). Body mass index (BMI) was defined using standard CDC definitions. Multivariate conditional logistic regression assessed associations between BMI and ALL with additional analyses stratified by sex and race/ethnicity.ResultsAmong cases (72% high‐risk (HR) B‐ALL, 28% T‐ALL), 5% had underweight, 58% normal weight, 17% overweight, and 20% obesity. Underweight (OR 2.11, 95% CI 1.56‐2.85) and obesity (OR 1.32, 95% CI 1.15‐1.53) were associated with B‐ALL diagnosis. Specifically, obesity was associated with B‐ALL among males (OR 1.57, 95% CI 1.30‐1.91) and Hispanic children (OR 1.78, 95% CI 1.39‐2.29). Obesity was also associated with central nervous system (CNS) involvement.ConclusionPre‐treatment obesity is associated with HR B‐ALL among males and Hispanics, as well as with CNS involvement, suggesting common physiology between obesity and leukemogenesis. An association between underweight and ALL was confirmed, likely due to cancer‐associated wasting. These results have important public health implications for obesity prevention and treatment in children and adolescents to reduce cancer risk.

The effect of the minimum residual disease on the risk of relapse at allogeneic hematopoietic stem cell transplantation in children, adolescents, and young adults with acute lymphoblastic leukemia

Minimal residual disease (MRD) is an independent predictor of relapse risk for childhood acute lymphoblastic leukemia(ALL). The aim of study to investigate impact MRD by real-time quantitative polymerase chain reaction before (day –21) andat +30 ± 10, +60 ± 10, +100 ± 10, +180 ± 10, +365 ± 10 days after hematopoietic stem cell transplantation (HSCT), and PCR-chimerismon transplant outcomes children with ALL. The study was approved by the Independent Ethics Committee and the Scientific Councilof the Belarusian Research Center for Pediatric Oncology, Hematology and Immunology (Republic of Belarus). Fifty one patientswith ALL underwent allogeneic transplantation in remission (period 12.2010–12.2017, median follow-up 2,8 years). 3-years eventfreesurvival (EFS) and cumulative incidence of relapse (CIR) were 71.6 ± 17.1% and 14.3 ± 14.3% respectively for patients (n = 7)with pre-transplant MRD &lt; 10-4 and 0% (n = 4, p = 0.0046) and 50.0 ± 29.2% (p = 0.3111) respectively for MRD ≥ 10-4. After HSCT(n = 29) 3-years EFS and CIR were 22.2 ± 13.9% and 66.7 ± 18.1% respectively for recipients (n = 9) with MRD ≥ 10-4 at leastin one analyzed point. In comparison, patients with MRD &lt; 10-4 at all points (n = 20) had EFS and CIR 70.0 ± 10.2% (p = 0.0172)(HR = 12.3; 95% CI: 2.33–64.87; p = 0.0031), and 5.0±5.0% (p = 0.0004) (HR = 50.7; 2.5–97.5% CI: 1.60–1608.56; p = 0.0260)respectively. Patients with mixed chimerism at least in one analyzed point since day +30 to +365 hadn't significant differences OS,EFS, CIR but were worse (57.1%, 40.0% and 50.0% respectively) in comparison full chimerism patients (79.5% (p = 0.248), 71.4%(p = 0.072) and 20.0% (p = 0.070) respectively). MRD is significant predictor of relapse risk for childhood ALL at time of HSCT.MRD &lt; 10-4 patients have significantly better EFS and CIR in comparison MRD ≥ 10-4 patients before and after HSCT.

Association of TLX1 gene polymorphisms with the risk of acute lymphoblastic leukemia and B lineage acute lymphoblastic leukemia in Han Chinese children

BackgroundStudies on gene polymorphism association are centered on childhood acute lymphoblastic leukemia (ALL), a common hematological malignancy in children younger than 16 years. Single‐nucleotide polymorphisms (SNPs) in some genes, such as ARID5B and CDKN2B, are associated with the risk of childhood ALL. T‐cell leukemia homeobox 1 (TLX1), a member of the HOX gene family, was identified based on its abnormal expression in T‐lineage leukemia. This study aimed to determine whether TLX1 is associated with B‐ALL and which SNP plays a significant role in ALL.MethodsA total of 217 cases of ALL and 241 controls were included in this study. Six tag SNPs (rs75329544, rs946328, rs12415670, rs2075879, rs17113735, and rs1051723) were selected, and genotyping was carried out on Sequenom MassARRAY platform.ResultsRs17113735 was possibly the risk locus associated with increased risk for ALL, whereas rs946328 was possibly associated with decreased risk for ALL. Moreover, rs17113735 was likely to be the risk locus for B‐cell ALL (B‐ALL), and rs2075879 was associated with decreased risk for B‐ALL (P < .05). All SNPs in the two sample types (ALL and B‐ALL samples) demonstrated linkage disequilibrium except between rs75329544 and rs2075879. Haplotype analysis showed no significant difference between the cases and controls in the two sample types.Conclusion TLX1 gene polymorphisms are associated with ALL (rs17113735 and rs946328) and possibly play a significant role in B‐ALL (rs17113735 and rs2075879). This work provides a reference for the diagnosis and therapy of this disease.

Abstract IA38: What causes the increased risk of acute lymphoblastic leukemia in Latinos?

Abstract Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and, despite high cure rates, remains one of the leading causes of cancer-related mortality in children. Moreover, childhood ALL survivors are faced with severe long-term treatment-related morbidities, including increased risk of cardiovascular disease, secondary cancers, and pulmonary disease. Children of Latino ethnicity have the highest incidence of ALL in the United States. This increased risk likely has a genetic component, although the rising incidence of ALL in recent decades, which is increasing fastest in Latinos, points towards a role for environmental exposures. In this talk, I will discuss recent research from our group and others that has shed light on the potential etiologies of the increased ALL risk in Latinos. Genome-wide association studies (GWAS) of childhood ALL have pinpointed several risk loci at genes involved in B-cell development and hematopoiesis. In our earlier studies of ALL in the genetically admixed Latino population of California, we capitalized on their altered linkage disequilibrium patterns (compared to non-Latino whites) to identify putative causal variants, including a missense SNP in CDKN2A. More recently, we performed a large multiethnic GWAS of ALL including Latinos, non-Latino whites, and African-Americans, and identified new ALL risk loci at 8q24 and IKZF3. Fine-mapping at known loci also helped to confirm an independent risk locus at chromosome 10p12.31 and pinpointed a likely causal variant in an enhancer region for BMI1. Our group and others previously showed that the risk allele frequencies of several loci, including ARID5B, PIP4K2A, and GATA3, are higher in Latino populations and are associated with Native American ancestry. In two recent, independent GWAS of ALL in Latinos, a novel risk locus was identified at the erythroblast transformation-specific (ETS)-related gene (ERG) on chromosome 21, which was found to confer stronger leukemia risk in Latinos than in non-Latino whites. Moreover, within Latinos the effect of this risk locus increased with increasing Native American ancestry. We subsequently confirmed ERG as the first identified genetic risk locus for ALL in children with Down syndrome (DS-ALL), in which the effect size was again stronger in Latino than in non-Latino white children with DS. Our research group has also identified varied associations between Latinos and non-Latino whites for risk factors pertaining to immune stimulation (childhood contacts) and infection (cytomegalovirus). Future studies of ALL risk factors in Latinos, including even larger GWAS, polygenic risk score analysis, admixture mapping, as well as continued investigation of environmental risk factors, will be critical for our understanding the etiology of this disease and for identifying possible avenues to reduce the ethnic disparity in ALL incidence. Citation Format: Adam J. de Smith, Qianxi Feng, Kyle M. Walsh, Soyoung Jeon, Libby M. Morimoto, Andrew T. DeWan, Charleston Chiang, Catherine Metayer, Xiaomei Ma, Joseph L. Wiemels. What causes the increased risk of acute lymphoblastic leukemia in Latinos? [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr IA38.

Association between genetic polymorphism of XRCC7 (G6721T) and risk of acute lymphoblastic leukemia

BackgroundThe DNA non-homologous end joining repair gene XRCC7 is one of the most important genes in the DNA double-strand break (DSBs) repair. It is supposed that DNA repair gene malfunction is the main risk factor in various malignancies. The XRCC7 G6721T (rs7003908) polymorphism impact was investigated on the splicing regulation that cause mRNA instability. The goal of the present hospital-based study was to investigate the association between the common genetic polymorphism of XRCC7 G6721T (rs7003908) and risk of acute lymphoblastic leukemia (ALL). This hospital-based case–control study was performed on 99 ALL patients versus 200 healthy children, as the control group, which were frequent matched by age with cases. The polymorphism of XRCC7 was determined using an RFLP-PCR technique.ResultsThe GT (OR = 1.485, 95% CI 0.765–2.334, P = 0.243) and TT (OR = 1.655, 95% CI 00.875–3.128, P = 0.121) genotypes had no significant effect on the risk of ALL, in comparison with the GG genotype. However, TT genotype (OR = 1.996, 95% CI 1.033–3.858, P = 0.04) after adjusting for the parents’ smoking pattern showed a significant impact.ConclusionsThese findings suggest that the TT genotype may increase the ALL susceptibility in children when facing with a tobacco smoke.

History of Early Childhood Infections and Acute Lymphoblastic Leukemia Risk Among Children in a US Integrated Health-Care System.

Surrogate measures of infectious exposures have been consistently associated with lower childhood acute lymphoblastic leukemia (ALL) risk. However, recent reports have suggested that physician-diagnosed early-life infections increase ALL risk, thereby raising the possibility that stronger responses to infections might promote risk. We examined whether medically diagnosed infections were related to childhood ALL risk in an integrated health-care system in the United States. Cases of ALL (n=435) diagnosed between 1994-2014 among children aged 0-14 years, along with matched controls (n=2,170), were identified at Kaiser Permanente Northern California. Conditional logistic regression was used to estimate risk of ALL associated with history of infections during first year of life and across the lifetime (up to diagnosis). History of infection during first year of life was not associated with ALL risk (odds ratio (OR)=0.85, 95% confidence interval (CI): 0.60, 1.21). However, infections with at least 1 medication prescribed (i.e., more "severe" infections) were inversely associated with risk (OR=0.42, 95% CI: 0.20, 0.88). Similar associations were observed when the exposure window was expanded to include medication-prescribed infections throughout the subjects' lifetime (OR=0.52, 95% CI: 0.32, 0.85).