Childhood Acute Lymphoblastic Leukemia Susceptibility Research Articles

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.

Commentary: Association between the miR-146a rs2910164 polymorphism and childhood acute lymphoblastic leukemia susceptibility in an Asian population.

GENERAL COMMENTARY article Front. Genet., 20 March 2023Sec. Statistical Genetics and Methodology Volume 14 - 2023 | https://doi.org/10.3389/fgene.2023.1134659

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.

The clinical relevance of inosine triphosphate pyrophosphohydrolase(Itpa) genotypes in pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a malignant lymphoid cells proliferation at early stage of differentiation, it is primarily a disease of children under six years of age ; approximately 80-85% are of precursor B-cell phenotype. With improvements in diagnosis and treatment, overall cure rate for children with ALL reached 85% in the developed world. Multiple recent studies indicate that genetic polymorphisms play an influential role in childhood ALL susceptibility, treatment response and prognosis.The purine analog mercaptopurine is a key medication for the successful treatment of childhood ALL, Inosine triphosphate pyrophosphatase (ITPA) is one of several enzymes whose job is to cleanse the nucleotide pool. It catalyze the pyrophosphohydrolysis of 6-thioITP and methylthioITP and prevents the accumulation of such potentially toxic compounds. Therefore, the end result is that the ITPase enzyme acts to reduce the amount of active forms of the 6-MP drug present in human cells.Characterization of ITPA deficiency by genotyping for the most common inactivating single-nucleotide polymorphisms can prospectively identify patients at higher risk of mercaptopurine toxicity which can subsequently influence the outcome of the patients.

MTHFR-C677T Gene Polymorphism and Susceptibility to Acute Lymphoblastic Leukemia in Children: A Meta-Analysis.

The association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism (rs1801133) and childhood acute lymphoblastic leukemia (ALL) is inconsistent. To explore the relationship between MTHFR-C677T polymorphism and susceptibility to childhood ALL. PubMed, EMBASE, Web of Science, CNKI, Wanfang, VIP, and other databases were searched from the establishment of the database to November 2019, and all the case-control studies that met the inclusion criteria were collected. Stata 15.0 was used for meta-analysis, with calculation of the odds ratio (OR) of the relationship between MTHFR-C677T polymorphism and childhood ALL susceptibility. Ethnicity was analyzed by subgroup analysis. A total of 26 studies were included in this meta-analysis, including 4,682 children with ALL and 7144 controls. The results showed that there was no significant difference in the comparison of population of allele model, dominant gene model, recessive gene model, homozygous gene model, heterozygous gene model, and the comparison of Caucasian children. The results of the Asian child analysis suggested that the combined OR of the dominant gene model (CC + CT versus TT), homozygous model (CC versus TT) and heterozygous model (CT versus TT) was 1.32 (95% confidence interval [CI]: 1.03-1.70), 1.37 (95% CI: 1.02-1.84), and 1.27 (95% CI: 1.01-1.59), respectively, with statistically significant differences. However, there was no significant difference between the allele model and recessive gene model among Asian children. The MTHFR C677T polymorphism is related to ALL in children, especially in Asian children. CC + CT, CC, and CT genotypes can increase the risk of ALL, but no association has been found in Caucasian children.

Family-based exome-wide association study of childhood acute lymphoblastic leukemia among Hispanics confirms role of ARID5B in susceptibility.

We conducted an exome-wide association study of childhood acute lymphoblastic leukemia (ALL) among Hispanics to confirm and identify novel variants associated with disease risk in this population. We used a case-parent trio study design; unlike more commonly used case-control studies, this study design is ideal for avoiding issues with population stratification bias among this at-risk ethnic group. Using 710 individuals from 323 Guatemalan and US Hispanic families, two inherited SNPs in ARID5B reached genome-wide level significance: rs10821936, RR = 2.31, 95% CI = 1.70–3.14, p = 1.7×10−8 and rs7089424, RR = 2.22, 95% CI = 1.64–3.01, p = 5.2×10−8. Similar results were observed when restricting our analyses to those with the B-ALL subtype: ARID5B rs10821936 RR = 2.22, 95% CI = 1.63–3.02, p = 9.63×10−8 and ARID5B rs7089424 RR = 2.13, 95% CI = 1.57–2.88, p = 2.81×10−7. Notably, effect sizes observed for rs7089424 and rs10821936 in our study were >20% higher than those reported among non-Hispanic white populations in previous genetic association studies. Our results confirmed the role of ARID5B in childhood ALL susceptibility among Hispanics; however, our assessment did not reveal any strong novel inherited genetic risks for acute lymphoblastic leukemia among this ethnic group.

1399 - Involvement of SNPS in CDKN2A/B locus in childhood acute lymphoblastic leukemia susceptibility in the Spanish population

1399 - Involvement of SNPS in CDKN2A/B locus in childhood acute lymphoblastic leukemia susceptibility in the Spanish population

Increased Risk of Thai Childhood Acute Lymphoblastic Leukemia with the MiR196a2 T>C Polymorphism

Objectives:This study assessed associations of the miR196a2 (rs11614913) T>C polymorphism withsusceptibility to childhood acute lymphoblastic leukemia (ALL) and clinical outcomes.Materials and Methods:Blood DNA samples from 104 childhood ALL patients and 180 healthy children were studied for the miR-196a2 (rs11614913) polymorphism using a polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) approach.Results:The frequency of the miR-196a2 (rs11614913) T allele in controls was 0.51 compared with 0.33 in ALL cases. In this study, CC, TC heterozygote and CC/TC genotypes were significantly associated with increase childhood ALL susceptibility compared with the TT wild type (OR =4.321, 95% CI = 2.091-8.930 p=0.000, OR = 2.248, 95% CI =1.103-4.579, p=0.024, OR = 2.921, 95% CI = 1.504-5.673 p=0.001, respectively). However, the miR-196a2 (rs11614913) T>C polymorphism was not associated with demographic data or clinico-pathological data in ALL cases.Conclusion:CC, TC and CC+TC genotypes of miR-196a2 (rs11614913) was significantly associated with increased susceptibility in Thai childhood ALL but not with clinical variables.

Identification of a novel susceptibility locus at 16q23.1 associated with childhood acute lymphoblastic leukemia in Han Chinese.

Recently, genome-wide association studies (GWAS) have identified several susceptibility loci for childhood acute lymphoblastic leukemia (ALL) in populations of European descent; only a few loci could be confirmed in Asian populations because of those populations' genetic heterogeneity. To identify genetic factors associated with childhood ALL risk in the Chinese population, we performed a three-stage GWAS of 1184 childhood ALL cases and 3219 non-ALL controls. The combined analysis identified a new locus (rs1121404 in WWOX) at 16q23.1 associated with childhood ALL susceptibility (odds ratio (OR) = 1.38, P = 5.29 × 10-10), especially in the subtype of B-ALL (OR = 1.39, P = 2.47 × 10-9). The functional studies subsequently revealed that the expression of WWOX in ALL bone marrow was significantly lower than that in normal bone marrow. The G allele of rs1121404 displayed significantly decreased levels of mRNA expression of WWOX These results suggest that WWOX plays an important role in the development of childhood ALL and provide new insights into the etiology of childhood ALL.

Role of glutathione S-transferase M1, T1 and P1 gene polymorphisms in childhood acute lymphoblastic leukemia susceptibility in a Turkish population

The variations between different individuals in the xenobiotic metabolizing enzymes' activity were shown to modify susceptibility to childhood acute lymphoblastic leukemia (ALL). Polymorphisms associated with genes coding for the glutathione S-transferase (GST) enzyme were known to affect the metabolism of different carcinogens. The aim of this study was to evaluate the influence of the GSTM1 and GSTT1 deletion polymorphisms, and the GSTP1 Ile105Val single nucleotide polymorphism (SNP) on the susceptibility to childhood ALL. The study was conducted in 95 children with ALL and 190 healthy control subjects from the Turkish population. The data revealed no difference in the prevalence of the GSTM1 and GSTT1 null genotypes between the childhood ALL patients and the controls. No association was found between GSTP1 Ile105Val variants and the susceptibility to childhood ALL, separately or in combination. Our findings suggested that the status of heritable GST polymorphism might not influence the risk of developing childhood ALL. Studies with a larger sample size are needed to evaluate and confirm the validity of our results.

The Association of Methylenetetrahydrofolate Reductase Genotypes with the Risk of Childhood Leukemia in Taiwan

BackgroundAcute lymphoblastic leukemia (ALL) is the most prevalent type of pediatric cancer, the causes of which are likely to involve an interaction between genetic and environmental factors. To evaluate the effects of the genotypic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) on childhood ALL risk in Taiwan, two well-known polymorphic genotypes of MTHFR, C677T (rs1801133) and A1298C (rs1801131), were analyzed to examine the extent of their associations with childhood ALL susceptibility and to discuss the MTHFR genotypic contribution to childhood ALL risk among different populations.Methodology/Principal FindingsIn total, 266 patients with childhood ALL and an equal number of non-cancer controls recruited were genotyped utilizing PCR-RFLP methodology. The MTHFR C677T genotype, but not the A1298C, was differently distributed between childhood ALL and control groups. The CT and TT of MTHFR C677T genotypes were significantly more frequently found in controls than in childhood ALL patients (odds ratios=0.60 and 0.48, 95% confidence intervals=0.42–0.87 and 0.24–0.97, respectively). As for gender, the boys carrying the MTHFR C677T CT or TT genotype conferred a lower odds ratio of 0.51 (95% confidence interval=0.32–0.81, P=0.0113) for childhood ALL. As for age, those equal to or greater than 3.5 years of age at onset of disease carrying the MTHFR C677T CT or TT genotype were of lower risk (odds ratio= 0.43 and 95% confidence interval=0.26–0.71, P=0.0016).ConclusionsOur results indicated that the MTHFR C677T T allele was a protective biomarker for childhood ALL in Taiwan, and the association was more significant in male patients and in patients 3.5 years of age or older at onset of disease.

Interaction Between IGF1 Polymorphisms and the Risk of Acute Lymphoblastic Leukemia in Chinese Children

Background/Aims: IGF1 is a key regulator in cell proliferation and apoptosis, and the 3' un-translated region (3'UTR) of the gene plays an important role in gene expression. For the first time, we explored the relationship between polymorphisms in the IGF1 3'UTR region and the risk of childhood acute lymphoblastic leukemia (ALL). Methods: Questionnaires were applied to collect epidemiological data. The genotypes of IGF1 polymorphisms were tested in a population of 744 ALL patients and 1088 cancer-free controls utilizing Taqman. Cell functional studies included real-time PCR, cell culture and transfection and luciferase assays. Results: We found that rs6214 homozygous AA genotype and rs6218 homozygous CC genotype were significantly associated with increased risk of childhood ALL. In addition, rs6218 CC genotype was associated with increased level of IGF1 mRNA in bone marrow, and the mutation in rs6218 led to aberrant binding capacity of hsa-miR-603 and hsa-miR-3941 in the 3'UTR of IGF1. Conclusion: Polymorphisms of rs6214 and rs6218 in the 3'UTR of IGF1 are associated with childhood ALL susceptibility, and the polymorphism of rs6218 is related with IGF1 expression at mRNA level.

Genomic evaluations of childhood acute lymphoblastic leukemia susceptibility across race/ethnicities.

Genomic evaluations of childhood acute lymphoblastic leukemia susceptibility across race/ethnicities.

High Resolution Melting Analyses For Genetic Variants in ARID5B and IKZF1 with Childhood Acute Lymphoblastic Leukemia Susceptibility Loci In Taiwan

Introduction Childhood acute lymphoblastic leukemia (ALL) is a heterogeneous disease including multiple subtypes, defined on the basis of cell lineage and chromosome anomalies. Previous genome-wide association (GWA) studies report that several ARID5B and IKZF1 single nucleotide polymorphisms (SNPs) are associated with the incidence of ALL. However, high resolution melting analysis (HRM) supplies a faster and more convenient technique to detect SNPs. We applied HRM to detect the SNPs in ARID5B and IKZF1 gene. Method Seventy-nine pediatric ALL patients and 80 healthy controls were enrolled. Polymorphic variants of IKZF1 (rs6964823, rs4132601, and rs6944602) and ARID5B (rs7073837, rs10740055, and rs7089424) were detected by HRM method. The SNPs were further analyzed the association with childhood ALL. Result We evaluated 6 mutations by PCR amplicons (81 -176 bp) using the 96-well Light Cycler system. The primer detail was listed in Table 1. The melting curve data showed the difference in normalized temperature and we easily and accurately extended application of HRM analysis to genotyping of IKZF1 (Figure 1) and ARID5B (Figure 2) gene variants. The genotype distribution and the allele frequencies of IKZF1 (rs6964823, rs4132601, and rs6944602) and ARID5B (rs7073837, rs10740055, and rs7089424) gene polymorphisms among cases and controls and their association with the risk of childhood ALL were shown in Table 2. The distribution of genotype rs7073837 in ARID5B was significantly different between the ALL group and the control group (P = 0.046), while the distributions for IKZF1 (rs6964823, rs4132601, and rs6944602) and ARID5B (rs10740055, and rs7089424) were not significantly different. In addition, we analyzed the association for those SNPs with B lineage ALL and found rs7073837 in ARID5B conferred a higher risk for B lineage ALL (odds ratio, OR = 1.70, 95% confidence interval, CI = 1.01-2.87, P = 0.049). Conclusion HRM was a practical method to detect SNPs in ARID5B and IKZF1 gene. We determined the rs7073837 in ARID5B was associated with the risk of childhood B lineage ALL. Disclosures: No relevant conflicts of interest to declare.

High-resolution melting analyses for genetic variants in ARID5B and IKZF1 with childhood acute lymphoblastic leukemia susceptibility loci in Taiwan

Childhood acute lymphoblastic leukemia (ALL), a heterogeneous disease that includes multiple subtypes is defined by cell lineage and chromosome anomalies. Previous genome-wide association studies have reported several ARID5B and IKZF1 single nucleotide polymorphisms (SNPs) associated with the incidence of ALL. High-resolution melting (HRM) analysis is a rapid and convenient technique to detect SNPs; we thereby detected SNPs in ARID5B and IKZF1 genes. We enrolled 79 pediatric ALL patients and 80 healthy controls. Polymorphic variants of IKZF1 (rs6964823, rs4132601, and rs6944602) and ARID5B (rs7073837, rs10740055, and rs7089424) were detected by HRM, and SNPs were analyzed for association with childhood ALL. The distribution of genotype rs7073837 in ARID5B significantly differed between ALL and controls (P=0.046), while those of IKZF1 (rs6964823, rs4132601, and rs6944602) and ARID5B (rs10740055 and rs7089424) did not. We analyzed the association for SNPs with B lineage ALL to find rs7073837 in ARID5B, conferring a higher risk for B lineage ALL (odds ratio, OR=1.70, 95% confidence interval, CI=1.01-2.87, P=0.049). HRM is a practical method to detect SNPs in ARID5B and IKZF1 genes. We found that rs7073837 in ARID5B correlated with a risk for childhood B lineage ALL.

Genetic variants in ARID5B and CEBPE are childhood ALL susceptibility loci in Hispanics

Recent genome-wide studies conducted in European Whites have identified novel susceptibility genes for childhood acute lymphoblastic leukemia (ALL). We sought to examine whether these loci are susceptibility genes among Hispanics, whose reported incidence of childhood ALL is the highest of all ethnic groups in California, and whether their effects differ between Hispanics and non-Hispanic Whites (NHWs). We genotyped 13 variants in these genes among 706 Hispanic (300 cases, 406 controls) and 594 NHW (225 cases, 369 controls) participants in a matched population-based case–control study in California. We found significant associations for the five studied ARID5B variants in both Hispanics (p values of 1.0 × 10−9 to 0.004) and NHWs (p values of 2.2 × 10−6 to 0.018). Risk estimates were in the same direction in both groups (ORs of 1.53–1.99 and 1.37–1.84, respectively) and strengthened when restricted to B-cell precursor high-hyperdiploid ALL (>50 chromosomes; ORs of 2.21–3.22 and 1.67–2.71, respectively). Similar results were observed for the single CEBPE variant. Hispanics and NHWs exhibited different susceptibility loci at CDKN2A. Although IKZF1 loci showed significant susceptibility effects among NHWs (p < 1 × 10−5), their effects among Hispanics were in the same direction but nonsignificant, despite similar minor allele frequencies. Future studies should examine whether the observed effects vary by environmental, immunological, or lifestyle factors.

ARID5B Genetic Polymorphisms Contribute to Racial Disparities in the Incidence and Treatment Outcome of Childhood Acute Lymphoblastic Leukemia

Recent genome-wide screens have identified genetic variations in ARID5B associated with susceptibility to childhood acute lymphoblastic leukemia (ALL). We sought to determine the contribution of ARID5B single nucleotide polymorphisms (SNPs) to racial disparities in ALL susceptibility and treatment outcome. We compared the association between ARID5B SNP genotype and ALL susceptibility in whites (> 95% European genetic ancestry; 978 cases and 1,046 controls) versus in Hispanics (> 10% Native American ancestry; 330 cases and 541 controls). We determined the relationships between ARID5B SNP genotype and ALL relapse risk in 1,605 children treated on the Children's Oncology Group (COG) P9904/9905 clinical trials. Among 49 ARID5B SNPs interrogated, 10 were significantly associated with ALL susceptibility in both whites and Hispanics (P < .05), with risk alleles consistently more frequent in Hispanics than in whites. rs10821936 exhibited the most significant association in both races (P = 8.4 × 10(-20) in whites; P = 1 × 10(-6) in Hispanics), and genotype at this SNP was highly correlated with local Native American genetic ancestry (P = 1.8 × 10(-8)). Multivariate analyses in Hispanics identified an additional SNP associated with ALL susceptibility independent of rs10821936. Eight ARID5B SNPs were associated with both ALL susceptibility and relapse hazard; the alleles related to higher ALL incidence were always linked to poorer treatment outcome and were more frequent in Hispanics. ARID5B polymorphisms are important determinants of childhood ALL susceptibility and treatment outcome, and they contribute to racial disparities in this disease.

An Allele of IKZF1 (Ikaros) Conferring Susceptibility to Childhood Acute Lymphoblastic Leukemia Protects Against Type 1 Diabetes

OBJECTIVEIKZF1 encoding Ikaros, an essential regulator of lymphopoiesis and immune homeostasis, has been implicated in the development of childhood acute lymphoblastic leukemia (C-ALL). Because recent genome-wide association (GWA) studies have linked a region of the 3′-UTR of IKZF1 with C-ALL susceptibility, we tested whether IKZF1 is associated with the autoimmune disease type 1 diabetes.RESEARCH DESIGN AND METHODSrs10272724 (T>C) near IKZF1 at 7p12 was genotyped in 8,333 individuals with type 1 diabetes, 9,947 control subjects, and 3,997 families of European ancestry. Association was tested using logistic regression in the case-control data and by the transmission disequilibrium test in the families. Expression data for IKZF1 by rs10272724 genotype were obtained using quantitative PCR of mRNA/cDNA generated from peripheral blood mononuclear cells from 88 individuals, whereas expression data for five other neighboring genes were obtained from the online Genevar dataset.RESULTSThe minor allele of rs10272724 (C) was found to be protective from type 1 diabetes (odds ratio 0.87 [95% CI 0.83–0.91]; P = 1.1 × 10−11). rs10272724 was not correlated with levels of two transcripts of IKZF1 in peripheral blood mononuclear cells.CONCLUSIONSThe major susceptibility genotype for C-ALL confers protection from type 1 diabetes. Our finding strengthens the link between autoimmunity and lymphoid cancers. Further investigation is warranted for the genetic effect marked by rs10272724, its impact on IKZF1, and the role of Ikaros and other family members, Ailios (IKZF3) and Eos (IKZF4), in autoimmunity.

Replication analysis confirms the association of ARID5B with childhood B-cell acute lymphoblastic leukemia

Although childhood acute lymphoblastic leukemia is the most common pediatric cancer, its etiology remains poorly understood. In an attempt to replicate the findings of 2 recent genome-wide association studies in a French-Canadian cohort, we confirmed the association of 5 SNPs [rs7073837 (P=4.2 x 10(-4)), rs10994982 (P=3.8 x 10(-4)), rs10740055 (P=1.6 x 10(-5)), rs10821936 (P=1.7 x 10(-7)) and rs7089424 (P=3.6 x 10(-7))] in the ARID5B gene with childhood acute lymphoblastic leukemia. We also confirmed a selective effect for B-cell acute lymphoblastic leukemia with hyperdiploidy and report a putative gender-specific effect of ARID5B SNPs on acute lymphoblastic leukemia risk in males. This study provides a strong rationale for more detailed analysis to identify the causal variants at this locus and to better understand the overall functional contribution of ARID5B to childhood acute lymphoblastic leukemia susceptibility.

Methylenetetrahydrofolate reductase polymorphisms, serum methylenetetrahydrofolate reductase levels, and risk of childhood acute lymphoblastic leukemia in a Chinese population

Methylenetetrahydrofolate reductase (MTHFR), involved in DNA methylation and nucleotide synthesis, is thought to be associated with a decreased risk of adult and childhood acute lymphoblastic leukemia (ALL). Accumulating evidence has indicated that two common genetic variants, C677T and A1298C, are associated with cancer risk. We hypothesized that these two variants were associated with childhood ALL susceptibility and influence serum MTHFR levels. We genotyped these two polymorphisms and detected MTHFR levels in a case-control study of 361 cases and 508 controls. Compared with the 677CC and 677CC/CT genotypes, the 677TT genotype was associated with a statistically significantly decreased risk of childhood ALL (odds ratio = 0.53, 95% confidence interval = 0.32-0.88, and odds ratio = 0.55, 95% confidence interval = 0.35-0.88, respectively). In addition, a pronounced reduced risk of ALL was observed among low-risk ALL and B-phenotype ALL. Moreover, the mean serum MTHFR level was 8.01 ng/mL (+/-4.38) in cases and 9.27 ng/mL (+/-4.80) in controls (P < 0.001). MTHFR levels in subjects with 677TT genotype was significantly higher than those with 677CC genotype (P = 0.010) or 677CT genotype (P = 0.043) in controls. In conclusion, our results provide evidence that the MTHFR polymorphisms might contribute to reduced childhood ALL risk in this population.