Risk Of Childhood Acute Lymphoblastic Leukemia Research Articles

Folate Metabolism and Risk of Childhood Acute Lymphoblastic Leukemia: A Genetic Pathway Analysis from the Childhood Cancer and Leukemia International Consortium.

Prenatal folate supplementation has been consistently associated with a reduced risk of childhood acute lymphoblastic leukemia (ALL). Previous germline genetic studies examining the one carbon (folate) metabolism pathway were limited in sample size, scope, and population diversity and led to inconclusive results. We evaluated whether ∼2,900 single-nucleotide polymorphisms (SNP) within 46 candidate genes involved in the folate metabolism pathway influence the risk of childhood ALL, using genome-wide data from nine case-control studies in the Childhood Cancer and Leukemia International Consortium (n = 9,058 cases including 4,510 children of European ancestry, 3,018 Latinx, and 1,406 Asians, and 92,364 controls). Each study followed a standardized protocol for quality control and imputation of genome-wide data and summary statistics were meta-analyzed for all children combined and by major ancestry group using METAL software. None of the selected SNPs reached statistical significance, overall and for major ancestry groups (using adjusted Bonferroni P-value of 5 × 10-6 and less-stringent P-value of 3.5 × 10-5 accounting for the number of "independent" SNPs). None of the 10 top (nonsignificant) SNPs and corresponding genes overlapped across ancestry groups. This large meta-analysis of original data does not reveal associations between many common genetic variants in the folate metabolism pathway and childhood ALL in various ancestry groups. Genetic variants in the folate pathway alone do not appear to substantially influence childhood acute lymphoblastic leukemia risk. Other mechanisms such as gene-folate interaction, DNA methylation, or maternal genetic effects may explain the observed associations with self-reported prenatal folate intake.

A noncoding regulatory variant in IKZF1 increases acute lymphoblastic leukemia risk in Hispanic/Latino children

Hispanic/Latino children have the highest risk of acute lymphoblastic leukemia (ALL) in the US compared to other racial/ethnic groups, yet the basis of this remains incompletely understood. Through genetic fine-mapping analyses, we identified a new independent childhood ALL risk signal near IKZF1 in self-reported Hispanic/Latino individuals, but not in non-Hispanic White individuals, with an effect size of ∼1.44 (95% confidence interval= 1.33-1.55) and a risk allele frequency of ∼18% in Hispanic/Latino populations and <0.5% in European populations. This risk allele was positively associated with Indigenous American ancestry, showed evidence of selection in human history, and was associated with reduced IKZF1 expression. We identified a putative causal variant in a downstream enhancer that is most active in pro-B cells and interacts with the IKZF1 promoter. This variant disrupts IKZF1 autoregulation at this enhancer and results in reduced enhancer activity in B cell progenitors. Our study reveals a genetic basis for the increased ALL risk in Hispanic/Latino children.

Exclusive Breastfeeding Duration and Risk of Childhood Cancers

Breastfeeding has been suggested to protect against childhood cancers, particularly acute lymphoblastic leukemia (ALL). However, the evidence stems from case-control studies alone. To investigate whether longer duration of exclusive breastfeeding is associated with decreased risk of childhood ALL and other childhood cancers. This population-based cohort study used administrative data on exclusive breastfeeding duration from the Danish National Child Health Register. All children born in Denmark between January 2005 and December 2018 with available information on duration of exclusive breastfeeding were included. Children were followed up from age 1 year until childhood cancer diagnosis, loss to follow-up or emigration, death, age 15 years, or December 31, 2020. Data were analyzed from March to October 2023. Duration of exclusive breastfeeding in infancy. Associations between duration of exclusive breastfeeding and risk of childhood cancer overall and by subtypes were estimated as adjusted hazard ratios (AHRs) with 95% CIs using stratified Cox proportional hazards regression models. A total of 309 473 children were included (51.3% boys). During 1 679 635 person-years of follow-up, 332 children (0.1%) were diagnosed with cancer at ages 1 to 14 years (mean [SD] age at diagnosis, 4.24 [2.67] years; 194 boys [58.4%]). Of these, 124 (37.3%) were diagnosed with hematologic cancers (81 [65.3%] were ALL, 74 [91.4%] of which were B-cell precursor [BCP] ALL), 44 (13.3%) with central nervous system tumors, 80 (24.1%) with solid tumors, and 84 (25.3%) with other and unspecified malignant neoplasms. Compared with exclusive breastfeeding duration of less than 3 months, exclusive breastfeeding for 3 months or longer was associated with a decreased risk of hematologic cancers (AHR, 0.66; 95% CI, 0.46-0.95), which was largely attributable to decreased risk of BCP-ALL (AHR, 0.62; 95% CI, 0.39-0.99), but not with risk of central nervous system tumors (AHR, 0.96; 95% CI, 0.51-1.88) or solid tumors (AHR, 0.87; 95% CI, 0.55-1.41). In this cohort study, longer duration of exclusive breastfeeding was associated with reduced risk of childhood BCP-ALL, corroborating results of previous case-control investigations in this field. To inform future preemptive interventions, continued research should focus on the potential biologic mechanisms underlying the observed association.

Time of Attainment of Clinical Remission and Peripheral Blood Count Recovery during Induction Chemotherapy for Childhood Acute Lymphoblastic Leukemia

Background: Acute lymphoblastic leukemia(ALL) is the most common pediatric malignancy. Infection and bleeding are the leading cause of death during induction chemotherapy in childhood ALL. So, proper knowledge about anticipated infection and bleeding are very important during this period. But the duration of clinical remission and recovery of peripheral blood count during induction chemotherapy is not well reported in literature. Objective: The aim of the study was to determine the time of attainment of clinical remission and recovery of peripheral blood count after initiation of induction chemotherapy and to determine if the duration of clinical remission and peripheral blood count recovery differs between therapeutic risk groups. Methods: This prospective observational study was conducted from January 2021 to December 2021 in the Department of Paediatric Haematology and Oncology, BSMMU. Newly diagnosed admitted Eighty-Six ALL of both sexes aged 1 to 17.9 years were included. After commencing chemotherapy, physical examination was recorded every day until clinical remission and complete blood count (CBC) was recorded one to two days interval until peripheral blood count recovery. The number of packed red blood cell (PRBC) and platelet transfusions and the number of days of intravenous antibiotics were recorded. Results: Mean duration of clinical remission, complete Hemoglobin (Hb), Absolute neutrophil count(ANC) and platelet recovery was 8.4 ± 4.5 days, 25±7.9 days, 23.3±5.6 days and 21.8±6.4 days respectively (p&lt;0.01). Time to attain partial recovery of platelet was 14.0±4.9 days in high risk and 19.2±5.3 days in standard risk group. PRBC transfusion requirement was 2.2±1.2 units in high risk group and 1.7±0.8 units in standard risk group (p&lt;0.05). Time to attain partial recovery of ANC, number of days with I/V antibiotics and duration of treatment interruption were higher in high risk group. Conclusion: Time of clinical remission was similar between risk group. Platelet recovery occurred earlier than Hemoglobin (Hb) and absolute neutrophil count (ANC) recovery. Transfusion and supportive care requirement were more in high risk group during induction chemotherapy. So, more supportive care should be arranged up to three weeks of induction period to increase survival of high risk childhood ALL. Bangladesh Med Res Counc Bull 2023; 49: 177-182

Interleukin-8 Rs4073 Genotypes as Prognostic Predictors for Childhood Acute Lymphocytic Leukemia.

Interleukin 8 (IL-8) is highly expressed in refractory acute lymphocytic leukemia (ALL) cells. This study aimed to investigate the contribution of IL-8 polymorphisms to the risk of childhood ALL. The genotypes of IL-8 rs4073, rs2227306, rs2227543, and rs1126647 were determined in 266 childhood ALL cases and 266 controls using the PCR-RFLP method. Additionally, we assessed whether the interactions of these genotypes with age and sex contributed to childhood ALL risk. The distributions of genotypic and allelic frequencies of IL-8 rs4073, rs2227306, rs2227543, and rs1126647 were not significantly different between childhood ALL cases and controls (all p>0.05). However, carriers of the variant AA genotype at IL-8 rs4073 had a significantly higher risk of childhood ALL among those aged ≤3.5 years and among girls (OR=2.39 and 3.32, 95%CI=1.21-4.73 and 1.51-7.30, p=0.0182 and 0.0042, respectively). In the stratification analysis, IL-8 rs4073 AT and AA genotypes were associated with higher childhood ALL risk classification and shorter survival time (OR=2.21 and 4.13, 95%CI=1.29-3.78 and 1.87-9.10, p=0.0054 and 0.0002, respectively). There was no positive association for rs2227306, rs2227543, or rs1126647 (all p>0.05). The A allele of IL-8 rs4073 can serve as a diagnostic predictor for childhood ALL, but only in girls and patients younger than or equal to 3.5 years old. More importantly, it can serve as a prognostic marker for high-risk classification and shorter survival time. Further validation studies can help extend the use of this prognostic predictor in clinical practice.

Heritable Variation in Lymphocyte-Related Traits and Risk of Down Syndrome Acute Lymphoblastic Leukemia: A Mendelian Randomization Study

Introduction: The risk of developing acute lymphoblastic leukemia (ALL) is up to 30-fold higher in children with Down syndrome (DS). While trisomy 21 increases the risk of leukemia, only ~1% of children with DS develop ALL (DS-ALL), suggesting that additional modifying risk factors exist. A recent study in individuals without DS revealed that a genetic propensity for increased lymphocyte production was associated with an increased risk of childhood ALL. Additionally, a previous genome-wide association study (GWAS) of DS-ALL identified associations in genes involved in lymphoid development. Here, we investigated whether genetic variation in lymphocyte-related traits is associated with DS-ALL risk, with the hypothesis that a genetic predisposition for lymphocyte overproduction is associated with an increased risk of DS-ALL. Methods: We performed Mendelian randomization (MR) analyses to investigate the potential causal relationship between variation in four lymphocyte-related traits - lymphocyte counts, the lymphocytes to monocytes ratio (LMR), the neutrophils to lymphocytes ratio (NLR), and the platelets to lymphocytes ratio (PLR) - and DS-ALL risk. Genetic variants associated with each lymphocyte-related trait (“exposure”) at P &amp;lt; 5x10 -8 and their corresponding effect sizes and standard errors were obtained from GWAS of blood cell traits performed in 413,810 cancer-free individuals of European ancestry in the UK Biobank. A GWAS of DS-ALL (“outcome”) was carried out using germline whole-genome sequencing data from 222 DS-ALL cases and 1,010 individuals without ALL from DS research cohorts, limited to individuals of non-Hispanic White race/ethnicity. We examined consistency across multiple MR methods, including the inverse-variance weighted (IVW), weighted median (WM), MR robust adjusted profile score (RAPS), and MR pleiotropy residual sum and outlier (PRESSO) estimators. Results: Among the lymphocyte-related traits, we found a significant association between LMR and DS-ALL risk that was consistent across MR estimators. Specifically, each 1-unit increase in LMR was associated with a 41%-53% decrease in ALL risk in children with DS (odds ratio [OR IVW] = 0.56; 95% CI: 0.35-0.90, p = 0.016; OR WM = 0.47; 95% CI: 0.21-1.04, p = 0.051; OR RAPS = 0.59; 95% CI: 0.36-0.97, p = 0.038; OR PRESSO = 0.55; 95% CI: 0.34-0.88, p = 0.014). There were no statistically significant associations between the remaining blood cell traits (lymphocyte count, PLR, and NLR) and DS-ALL risk, although increased lymphocyte counts conferred a modest increase in risk of DS-ALL (OR IVW=1.24, p=0.40). Conclusions: We discovered that genetic predisposition to shifts in the ratio of lymphocytes relative to monocytes may be a novel risk factor for the development of DS-ALL, with a deficit of lymphocytes to monocytes conferring an increased risk of DS-ALL. This observed direction of effect contrasts with previous findings for ALL in the non-DS population, suggesting a distinct etiology of ALL in the context of DS that may be influenced by the profound effects of trisomy 21 on immune function. Replication of our findings in independent DS-ALL studies is underway, and analysis of polygenic risk scores for lymphocyte traits may further improve identification of children with a high risk of DS-ALL.

Childhood acute lymphoblastic leukemia survival and spatial analysis of socio-environmental risks in Mexico.

Acute lymphoblastic leukemia (ALL) etiology remains largely unknown; incidence patterns by age, sex, and geographical distribution suggest a potential environmental role. To identify ALL clusters from four contrasting urban areas of Mexico and to characterize the sources of environmental carcinogens. Hospital-based ALL cases (n = 443) diagnosed in children <19 years old from the Metropolitan Zones of Merida and San Luis Potosi, the State of Mexico, and Tijuana were analyzed (2015-2020). ALL cases were coded according to the International Classification of Diseases for Oncology. ALL clusters were identified by Kernel Density, and excess risk was estimated. Data of particulate matter ≤2.5 µm (PM2.5) concentrations measured by community-monitoring stations were analyzed. Geocoded datasets of benzene, polycyclic aromatic hydrocarbons, and PM2.5 sources were analyzed to characterize patterns of exposure in ALL clusters. The survival rate for ALL ranged from 61.5% to 78.6%. Seven ALL clusters with excess risk (RR 1.4-2.3, p < 0.05) were identified. The carcinogen sources included artisanal brick kilns, gas stations, cement works, carpentry, paint, and chemical manufacturing establishments. PM2.5 levels ranged from 15 µg/m3 to 37 µg/m3 among study areas. ALL clusters were identified at the community level; the excess risk could be explained by small-scale carcinogen sources. The levels of PM2.5 in outdoor air ranged from 3 to 6 times above the World Health Organization (WHO) air quality guidelines. Healthcare providers must raise awareness of the increased risk of ALL in children living near sources of environmental carcinogens; cancer control and prevention strategies must be steered from a multi-sectoral and multi-action perspective to protect children's health.

Maternal medically diagnosed infection and antibiotic prescription during pregnancy and risk of childhood cancer: A population-based cohort study in Taiwan, 2004 to 2015.

While associations between maternal infections during pregnancy and childhood leukemia in offspring have been extensively studied, the evidence for other types of childhood cancers is limited. Additionally, antibiotic exposure during pregnancy could potentially increase the risk of childhood cancers. Our study investigates associations between maternal infections and antibiotic prescriptions during pregnancy and the risk of childhood cancer in Taiwan. We conducted a population-based cohort study using the Taiwan Maternal and Child Health Database (TMCHD), linked with national health and cancer registries. The study included 2 267 186 mother-child pairs, and the median follow-up time was 7.96 years. Cox proportional hazard models were utilized to estimate effects. Maternal infections during pregnancy were associated with a moderate increase in the risk of childhood hepatoblastoma (adjusted hazard ratio [HR] = 1.34; 95% confidence interval [CI]: 0.90-1.98) and a weaker increase in the risk of childhood acute lymphoblastic leukemia (ALL) (adjusted HR = 1.15; 95% CI: 0.99-1.35). Antibiotic prescriptions during pregnancy were also associated with an elevated risk of childhood ALL (adjusted HR = 1.30; 95% CI: 1.04-1.63), particularly with tetracyclines (adjusted HR = 2.15; 95% CI: 1.34-3.45). Several specific antibiotics were also associated with an increased risk of hepatoblastoma and medulloblastoma. Children exposed in utero to antibiotic prescription or both infections and antibiotics during pregnancy were at higher risk of developing ALL. Our findings suggest that there are associations between maternal infections, antibiotic use during pregnancy and the risk of several childhood cancers in addition to ALL and highlight the importance of further research in this area.

Gene-Environment Analyses Reveal Novel Genetic Candidates with Prenatal Tobacco Exposure in Relation to Risk for Childhood Acute Lymphoblastic Leukemia.

Associations between maternal tobacco exposure during pregnancy and childhood acute lymphoblastic leukemia (ALL) have yielded mixed results. This may be due to biases in self-reported smoking or other differences in individual-level risk factors. We utilized a biological marker of maternal tobacco exposure to evaluate the association between maternal tobacco exposure during pregnancy, genetics, and subsequent childhood ALL risk in two large population-based studies of childhood ALL in California. Maternal exposure to tobacco smoke was assessed with a validated methylation marker (cg05575921) of the aryl hydrocarbon receptor repressor (AHRR) gene in newborn dried blood spots. We adjusted for sex, birthweight, gestational age, mode of delivery, year of birth, AHRR quantitative trait locus (mQTL) rs77111113, and a polygenetic risk score for childhood ALL. We additionally adjusted for principal components in a gene-environment interaction testing method that incorporates gene-only and environment-only effects along with interactions. AHRR hypomethylation overall was not associated with childhood ALL. In gene-environment interaction testing, several genetic variants displayed significant interaction with AHRR hypomethylation and childhood ALL. Our results suggest that novel candidates in PTPRK and DPP6 may play a role in tobacco-related leukemogenesis. Further research is necessary to better understand the effects of tobacco and these variants on childhood ALL risk. Despite the lack of an overall "main effect," tobacco exposure during pregnancy affects childhood ALL risk depending on specific genetic variants.

PI3K/AKT pathway-related microRNA variants in childhood acute lymphoblastic leukemia.

Dysregulation of microRNAs (miRNAs) targeting genes in the PI3K/Akt pathway has been implicated in the pathogenesis of childhood acute lymphoblastic leukemia (ALL). However, the impact of genetic variants in these miRNAs on ALL susceptibility has not been extensively explored in the Chinese population. To address this gap, we conducted a case-control study to evaluate the association between genetic variants in five PI3K/AKT pathway-related miRNAs (miR-149, miR-126, miR-492, miR-612, and miR-423) and childhood ALL susceptibility in the Chinese population. Additionally, we investigated the effects of the rs2292832 mutation on ALL cell proliferation and apoptosis. Our analyses revealed that the miR-149 rs2292832 mutant heterozygous CT genotype was more frequent in the control group than in the ALL cases, indicating a protective effect against ALL (adjusted odds ratio [OR]=0.78, 95% confidence interval [CI]=0.63-0.97, p=.024). Stratification analyses further revealed that the miR-149 rs2292832 CC genotype was associated with an increased risk of childhood ALL in subgroups of older children, females, those with parents who never smoked or drank alcohol, those living in painted houses, those with B-ALL, and those with high-risk ALL. Finally, we observed that the rs2292832 mutation inhibited ALL cell proliferation and induced apoptosis (p=.001), providing a potential mechanism by which this genetic variant may influence ALL susceptibility. Our study highlights the significant association between the miR-149 rs2292832 genetic variant and childhood ALL susceptibility in the Chinese population. These findings expand our understanding of the complex genetic landscape underlying ALL and have implications for the development of personalized therapeutic strategies.

Contributions of ARID5B, IKZF1, PIP4K2A, and GATA3 Gene Polymorphisms to Childhood Acute Lymphoblastic Leukemia in a Chinese Population.

Various studies have shown that single nucleotide polymorphisms in the AT-rich interaction domain 5B (ARID5B), IKAROS family zinc finger 1 (IKZF1), phosphatidylinositol-5-phosphate 4-kinase type 2 alpha (PIP4K2A), and GATA binding protein 3 (GATA3) genes may be associated with the susceptibility and prognosis of childhood acute lymphoblastic leukemia (ALL). The present study aimed to investigate the association of ARID5B rs10821936, IKZF1 rs4132601, PIP4K2A rs7088318, and GATA3 rs3824662 gene polymorphisms with the susceptibility and prognosis of childhood ALL in China. We found that the C allele of rs10821936 (ARID5B) and the A allele of rs3824662 (GATA3) were associated with an increased risk of childhood ALL in the Chinese population. There was no significant difference in frequencies of rs4132601 (IKZF1) and rs7088318 (PIP4K2A) genotypes and alleles between the childhood ALL and control groups. We observed that CC genotype of rs10821936 (ARID5B) was associated with increased rates of high-risk and moderate-risk childhood ALL. The rs10821936 (ARID5B) could serve as a potential biomarker for assessing the risk of childhood ALL in Chinese children.

Glyphosate in house dust and risk of childhood acute lymphoblastic leukemia in California

BackgroundResidential use of pesticides has been associated with increased risk of childhood acute lymphoblastic leukemia (ALL). We evaluated determinants of glyphosate concentrations in house dust and estimated ALL risk in the California Childhood Leukemia Study (CCLS). MethodsThe CCLS is a population-based case-control study of childhood leukemia in California. Among those < 8-years (no move since diagnosis/reference date), we collected dust (2001–2007) from the room where the child spent the most time while awake and measured > 40 pesticides. Three-to-eight years later, we collected a second sample from non-movers. We used Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry to measure glyphosate (µg/g dust) for 181 ALL cases and 225 controls and for 45 households with a second dust sample. We used multivariable Tobit regression to evaluate determinants of glyphosate concentrations. Odds ratios (ORs) and 95 % confidence intervals (CI) were calculated for ALL and quartiles of the concentration (first samples) using unconditional logistic regression. We computed the within- and between-home variance and intraclass correlation coefficient (ICC). ResultsGlyphosate was frequently detected (cases: 98 %; controls: 99 %). Higher concentrations were associated with occupational pesticide exposure, nearby agricultural use, treatment for lawn weeds and bees/wasps, and sampling season. Increasing concentrations were not associated with ALL risk (adjusted ORQ4vsQ1 = 0.8, CI: 0.4–1.4). We observed similar null associations for boys and girls, Hispanics and non-Hispanic whites, and among those who resided in their home since birth (76 cases/117 controls) or age two (130 cases/176 controls). The ICC was 0.32 indicating high within-home temporal variability during the years of our study. ConclusionsWe observed higher concentrations in homes associated with expected predictors of exposure but no association with childhood ALL risk. Due to continuing use, potential exposure to young children is high. It will be important to evaluate risk in future studies with multiple dust measurements or biomarkers of exposure.

Outdoor artificial light at night, air pollution, and risk of childhood acute lymphoblastic leukemia in the California Linkage Study of Early-Onset Cancers

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children (age 0–14 years); however, the etiology remains incompletely understood. Several environmental exposures have been linked to risk of childhood ALL, including air pollution. Closely related to air pollution and human development is artificial light at night (ALAN), which is believed to disrupt circadian rhythm and impact health. We sought to evaluate outdoor ALAN and air pollution on risk of childhood ALL. The California Linkage Study of Early-Onset Cancers is a large population-based case–control in California that identifies and links cancer diagnoses from the California Cancer Registry to birth records. For each case, 50 controls with the same year of birth were obtained from birth records. A total of 2,782 ALL cases and 139,100 controls were identified during 2000–2015. ALAN was assessed with the New World Atlas of Artificial Night Sky Brightness and air pollution with an ensemble-based air pollution model of particulate matter smaller than 2.5 microns (PM2.5). After adjusting for known and suspected risk factors, the highest tertile of ALAN was associated with an increased risk of ALL in Hispanic children (odds ratio [OR] = 1.15, 95% confidence interval [CI] 1.01–1.32). There also appeared to be a borderline association between PM2.5 level and risk of ALL among non-Hispanic White children (OR per 10 µg/m3 = 1.24, 95% CI 0.98–1.56). We observed elevated risk of ALL in Hispanic children residing in areas of greater ALAN. Further work is needed to understand the role of ALAN and air pollution in the etiology of childhood ALL in different racial/ethnic groups.

Childcare attendance and risk of childhood acute lymphoblastic leukaemia: A register study based on the Danish childcare database.

Childhood acute lymphoblastic leukaemia (ALL) is suggested to result from a dysregulated immune response to infections in children with a preleukaemic state. Childcare in early life supposedly may protect against childhood ALL by facilitating sufficient exposure to infections to stimulate and ensure normal maturation of the immune system. We assessed the association between childcare attendance before age 2 years and risk of childhood ALL in a register-based cohort study, including all children aged 2 to 14 years born in Denmark during 1991 to 2014 with available childcare information recorded in the Danish Childcare Database (n=1 116 185). Cox regression was used to estimate hazard ratios (HRs) comparing children enrolled in childcare and children not enrolled before age 2 years. Further, we assessed the association according to age at enrolment, type of childcare facility and specific ALL subtypes. During 10 460 811 person-years of follow-up, 460 children developed ALL at ages 2 to 14 years. Of these, 57 (12.4%) never attended childcare before age 2 years compared with 10.6% in the total cohort. Compared with homecare, childcare attendance before age 2 years was associated with a statistically non-significantly, marginally decreased risk of childhood ALL with adjusted HR=0.87 (95% confidence interval [CI]: 0.65-1.16). Risk estimates did neither vary statistically significantly by age at enrolment nor by type of childcare facility and also not between childhood ALL subtypes, including frequently prenatally initiated ALL subtypes. Results from this large, nationwide register-based study provided no evidence that childcare attendance in the first years of life protects against childhood ALL.

Racial and Ethnic Disparities in Childhood Acute Lymphoblastic Leukemia Risk Due to an IKZF1 Noncoding Regulatory Variant

Racial and Ethnic Disparities in Childhood Acute Lymphoblastic Leukemia Risk Due to an IKZF1 Noncoding Regulatory Variant

PAX5 fusion genes are frequent in poor risk childhood acute lymphoblastic leukaemia and can be targeted with BIBF1120.

SummaryBackgroundDespite intensive risk-based treatment protocols, 15% of paediatric patients with B-Cell Precursor Acute Lymphoblastic Leukaemia (BCP-ALL) experience relapse. There is urgent need of novel strategies to target poor prognosis subgroups, like PAX5 translocated.MethodsWe considered 289 childhood BCP-ALL cases consecutively enrolled in Italy in the AIEOP-BFM ALL2000/R2006 protocols and we performed extensive molecular profiling, integrating gene expression, copy number analyses and fusion genes discovery by target-capture NGS. We developed preclinical strategies to target PAX5 fusion genes.FindingsWe identified 135 cases without recurrent genetic rearrangements. Among them, 59 patients (43·7%) had a Ph-like signature; the remaining cases were identified as ERG-related (26%), High-Hyperdiploid-like (17%), ETV6::RUNX1-like (8·9%), MEF2D-rearranged (2·2%) or KMT2A-like (1·5%). A poor prognosis was associated with the Ph-like signature, independently from other high-risk features.Interestingly, PAX5 was altered in 54·4% of Ph-like compared to 16·2% of non-Ph-like cases, with 7 patients carrying PAX5 fusions (PAX5t), involving either novel (ALDH18A1, IKZF1, CDH13) or known (FBRSL1, AUTS2, DACH2) partner genes. PAX5t cases have a specific driver activity signature, extending to multiple pathways including LCK hyperactivation. Among FDA-approved drugs and inhibitors, we selected Dasatinib, Bosutinib and Foretinib, in addition to Nintedanib, known to be LCK ligands. We demonstrated the efficacy of the LCK-inhibitor BIBF1120/Nintedanib, as single agent or in combination with conventional chemotherapy, both ex vivo and in patient-derived xenograft model, showing a synergistic effect with dexamethasone.InterpretationThis study provides new insights in high-risk Ph-like leukaemia and identifies a potential therapy for targeting PAX5-fusion poor risk group.FundingRicerca Finalizzata-Giovani Ricercatori (Italian Ministry of Health), AIRC, Transcall, Fondazione Cariparo.

Investigating DNA methylation as a mediator of genetic risk in childhood acute lymphoblastic leukemia.

Genome-wide association studies have identified a growing number of single nucleotide polymorphisms (SNPs) associated with childhood acute lymphoblastic leukemia (ALL), yet the functional roles of most SNPs are unclear. Multiple lines of evidence suggest that epigenetic mechanisms may mediate the impact of heritable genetic variation on phenotypes. Here, we investigated whether DNA methylation mediates the effect of genetic risk loci for childhood ALL. We performed an epigenome-wide association study (EWAS) including 808 childhood ALL cases and 919 controls from California-based studies using neonatal blood DNA. For differentially methylated CpG positions (DMPs), we next conducted association analysis with 23 known ALL risk SNPs followed by causal mediation analyses addressing the significant SNP-DMP pairs. DNA methylation at CpG cg01139861, in the promoter region of IKZF1, mediated the effects of the intronic IKZF1 risk SNP rs78396808, with the average causal mediation effect (ACME) explaining ~30% of the total effect (ACME P = 0.0031). In analyses stratified by self-reported race/ethnicity, the mediation effect was only significant in Latinos, explaining ~41% of the total effect of rs78396808 on ALL risk (ACME P = 0.0037). Conditional analyses confirmed the presence of at least three independent genetic risk loci for childhood ALL at IKZF1, with rs78396808 unique to non-European populations. We also demonstrated that the most significant DMP in the EWAS, CpG cg13344587 at gene ARID5B (P = 8.61×10-10), was entirely confounded by the ARID5B ALL risk SNP rs7090445. Our findings provide new insights into the functional pathways of ALL risk SNPs and the DNA methylation differences associated with risk of childhood ALL.

Association of TP53 gene polymorphisms with the risk of acute lymphoblastic leukemia in Moroccan children.

TP53 gene plays a pivotal role in maintaining genetic stability and prevention of malignancies. Alterations of this gene are implicated in more than half of human cancers. To the best of our knowledge, this study is the first to explore TP53 polymorphisms in Moroccan childhood acute lymphoblastic leukemia (ALL). DNA samples of 45 ALL children were obtained from peripheral blood. A total of 333 healthy Moroccans were used as controls. Polymerase chain reaction and Sanger sequencing were performed to analyze TP53 hotspot exons in cases. We identified a significant protective effect of the TP53-Arg variant at rs1042522 [OR 0.4593 (0.249-0.8472), p = 0.0127] and the Pro/Arg genotype [OR 0.0350 (0.0047-0.2583), p = 0.0010]. Additionally, we found a novel association between the C-allele of Arg213Arg 1800372 [OR 2.7736 (1.3821-5.5664), p = 0.0041] and the risk of childhood ALL. Importantly, TC/CC genotypes of this polymorphism were revealed to enhance the risk of ALL among females [OR 9.0 (3.1555-25.6693), p < 0.0001]. Arg213Arg was also noticed to be associated with the hemoglobin count of patients at diagnosis by linear regression (p = 0.0318). The analysis of penetrance showed a significant association of the CG/GG genotypes at rs1042522 and TC/CC genotypes at rs1800372 to childhood ALL via dominant model [OR 0.2090 (0.09074-0.4814), p = 0.0002 and OR 3.4205 (1.6084-7.2742), p = 0.0014 for rs1042522 and rs1800372 respectively]. No association was found between TP53 polymorphisms and patients survival. Altogether, our findings indicated that TP53 polymorphisms are significantly involved in the genetic susceptibility to childhood ALL in Morocco.

Contribution of Cyclin-dependent Kinase Inhibitor 1B Genotypes to Childhood Leukemia Risk.

Although genetic differences in cell-cycle control genes have been associated with cancer risk, to our knowledge, no report has specifically examined the role of gene variants in childhood acute lymphoblastic leukemia (ALL). Cyclin-dependent kinase inhibitor 1B (CDKN1B; also known as p27/KIP1) is a cell-cycle regulating gene. This study aimed at investigating the association between CDKN1B genotypes and childhood ALL risk. In 266 childhood ALL cases and 266 healthy controls, the CDKN1B rs34330 and 2066827 polymorphisms were genotyped, and the association of CDKN1B genotypes with childhood ALL risk were analyzed. The genotypes of CDKN1B rs34330 and 2066827 were similarly distributed between the control and case groups (p for trend=0.8718 and 0.4030, respectively). The allelic frequency also exhibited no statistical difference (p=1.0000 and 0.6666, respectively). There was no significant interaction between CDKN1B genotypes and age or sex. CDKN1B genotypes were not found to be minor contributors to childhood ALL susceptibility in Taiwan.

PAX5 Fusion Genes are Frequent in Poor Risk Childhood Acute Lymphoblastic Leukaemia and Can Be Targeted with BIBF1120

PAX5 Fusion Genes are Frequent in Poor Risk Childhood Acute Lymphoblastic Leukaemia and Can Be Targeted with BIBF1120