Methylenetetrahydrofolate reductase (MTHFR) polymorphisms and risk of molecularly defined subtypes of childhood acute leukemia

MTHFR A1298C polymorphism: a predictor of reduced risk of preeclampsia in Punjab, Pakistan

OBJECTIVES

This study aimed to investigate the genetic association between MTHFR (A1298C) SNP and preeclampsia (PE) in Punjab, Pakistan.

METHODS

A sample of 80 pregnant women (40 healthy pregnant women and 40 with PE) was pooled for genotyping MTHFR A1298C polymorphism by using the tetra-primer amplification refractory mutation system (ARMS) PCR. The Genotypic and allelic assessments were performed using various statistical techniques.

RESULTS

The AC genotype and C allele of MTHFR A1298C were found to be associated with decreased risk of PE (odds ratio [OR]: 0.31, risk ratio [RR]: 0.58, p = 0.01), and (odds ratio [OR]: 0.49, risk ratio [RR]: 0.61, p = 0.04), respectively.

CONCLUSION

In conclusion, genetic polymorphism A1298C in MTHFR may pose a protective effect in the studied population.

Susceptibility to hypertension based on MTHFR rs1801133 single nucleotide polymorphism and MTHFR promoter methylation

Background

The aetio-pathologenesis of hypertension is multifactorial, encompassing genetic, epigenetic, and environmental factors. The combined effect of genetic and epigenetic changes on hypertension is not known. We evaluated the independent and interactive association of MTHFR rs1801133 single nucleotide polymorphism (SNP) and MTHFR promoter methylation with hypertension among Taiwanese adults.

Methods

We retrieved data including, MTHFR promoter methylation, MTHFR rs1801133 genotypes (CC, CT, and TT), basic demography, personal lifestyle habits, and disease history of 1,238 individuals from the Taiwan Biobank (TWB).

Results

The distributions of hypertension and MTHFR promoter methylation quartiles (β < 0.1338, 0.1338 ≤ β < 0.1385, 0.1385 ≤ β < 0.1423, and β ≥ 0.1423 corresponding to

Conclusion

Independently, rs1801133 TT was associated with a higher risk of hypertension, but methylation was not. Based on genotypes, lower methylation was dose-dependently associated with a higher risk of hypertension in individuals with the CC genotype. Our findings suggest that MTHFR rs1801133 and MTHFR promoter methylation could jointly influence hypertension susceptibility.

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Key Words

• MTHFR
• hypertension
• interaction
• promoter methylation
• rs1801133
• susceptibility

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MESH Headings Collapse

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Affiliation(s)

Ming-Huang Chiu Department of Pulmonology and Respiratory Care, Cathay General Hospital, Taipei City, Taiwan
Chia-Hsiu Chang Cardiovascular Center, Cathay General Hospital, Taipei City, Taiwan
Disline Manli Tantoh Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung City, Taiwan Department of Public Health and Institute of Public Health, Chung Shan Medical University, Taichung City, Taiwan
Tsui-Wen Hsu Superintendent Office, Institute of Medicine, Cathay General Hospital, Taipei City, Taiwan
Chih-Hsuan Hsiao Department of Public Health and Institute of Public Health, Chung Shan Medical University, Taichung City, Taiwan
Ji-Han Zhong Department of Public Health and Institute of Public Health, Chung Shan Medical University, Taichung City, Taiwan
Yung-Po Liaw Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung City, Taiwan Department of Public Health and Institute of Public Health, Chung Shan Medical University, Taichung City, Taiwan Institute of Medicine, Chung Shan Medical University, Taichung City, Taiwan

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Periconceptional folate intake influences DNA methylation at birth based on dietary source in an analysis of pediatric acute lymphoblastic leukemia cases and controls

BACKGROUND

Periconceptional folate intake is associated with the establishment of DNA methylation in offspring; however, variations in this relation by food sources compared with folic acid supplements are not described. Also, maternal folate intake is associated with decreased risk of pediatric acute lymphoblastic leukemia (ALL), but the mechanism is not known.

OBJECTIVES

We evaluated the relation between periconceptional folate intake by source and DNA methylation at birth in a cohort of pediatric ALL cases and controls in an epigenome-wide association study.

METHODS

Genome-wide DNA methylation status obtained from archived neonatal blood spots from pediatric ALL cases (n = 189) and controls (n = 205) in the California Childhood Leukemia Study (CCLS) from 1995-2008 was compared with periconceptional folate from total, food, and supplemental sources using multivariable linear regression. Further stratification was performed by income, education, ethnicity, and total folate intake. We evaluated variable DNA methylation response to periconceptional folate by ALL case status through an interaction term.

RESULTS

Two significant differentially methylated probes (DMPs) were associated with food and supplemental periconceptional folate intake in all subjects (n = 394). The top differentially methylated region at the promoter region of DUSP22(dual specificity phosphatase 22) demonstrated DNA hypermethylation in ALL cases but not in controls in response to total and food folate intake. We further identified 8 interaction term DMPs with variable DNA methylation response to folate intake by ALL case status. Further stratification of the cohort by education and ethnicity revealed a substantially higher number of DMPs associated with supplemental folic acid intake in Hispanic subjects with lower income and educational level.

CONCLUSIONS

We identified modest associations between periconceptional folate intake and DNA methylation differing by source, including variation by ALL case status. Hispanic subjects of lower income and education appear uniquely responsive to periconceptional folate supplementation.

Large-scale screening for factor V Leiden (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations in Greek population

Background and aims

To provide a fair estimate of the prevalence of factor V Leiden (FVL) (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations in the Greek population.

Methods

We genotyped a representative sample of 974 apparently healthy Greek adults by the method of real‐time PCR and we calculated the allele frequencies of factor V Leiden (FVL) (G1691A), prothrombin (G20210A), and MTHFR (C677T) mutations. In addition, we determined the frequency of co‐occurrence of FVL (1691A) and prothrombin (20210A), FVL (1691A) and MTHFR (677T), prothrombin (20210A) and MTHFR (677T) mutations.

Results

Τhe career frequencies of FVL (1691A), prothrombin (20210A), and MTHFR (677T) alleles were 7.5%, 4.5%, and 49.3% while the allele frequencies were 4%, 2.25%, and 39.5%, respectively. The coexistence of the allele frequencies combinations of two, FVL (1691A) and Prothrombin (20210A), FVL (1691A) and MTHFR (677T), prothrombin (20210A) and MTHFR (677T) was found in 1 (0.9%), 29 (3.5%), and 22 (3%) samples, respectively. Triple heterozygous carriers were not found.

Conclusion

Allele frequencies of the two (FVL and MTHFR) mutations are higher compared with published data. The large sample size of our study enhances the validity of our results and suggests a biological affinity of Greek population with Southern Italian populations.

Update meta-analysis from biomedical literature about MTHFR'polymorphisms and the CML' risk

BACKGROUND

The MTHFR gene polymorphisms are closely related to the chronic myeloid leukemia (CML). Case-control studies have associated the MTHFR polymorphisms and susceptibility to CML but the results were not conclusive.

AIM

To assess this association through an update meta-analysis.

METHODS

A descriptive and qualitative study was conducted among students in the 6th year of the faculty during the academic year 2020/2021. The data were collected through a questionnaire written in french evaluating the teaching methods. A focus group of ten persons was led to understand better student's opinions.

RESULTS

Totally, 17 and 12 case-control studies including CML cases and controls were enrolled in the meta-analysis respectively for C677T and A1298C polymorphism and CML risk. A poor association between the C677T (T vs C ; OR= 1,28; IC95%= [1,01;1,63]; p=0,04) and the one not significant between the A1298C (C vs A ; OR= 1,52; IC95%= [0,92; 2,51]; p= 0,1) polymorphisms and the CML risk for overall population were found.

CONCLUSION

The results of this meta-analysis suggested no significant association between C677T and A1298C polymorphisms and CML risk leading to consider other factors such us folic acid intake, gene-gene and gene- environment interactions.

Pharmacological mechanism of mylabris in the treatment of leukemia based on bioinformatics and systematic pharmacology

Leukemia is a common blood cancer, whose treatment usually necessitates chemo/radiotherapy and bone marrow transplant. Hence, safer and more effective options are urgently needed. Mylabris, the dried body of blister beetles, has been used extensively in traditional Chinese medicine. This study applied bioinformatics and systematic pharmacology to investigate the mechanism of action of mylabris in the treatment of leukemia. Five effective components and 35 corresponding target proteins were identified by screening the TCMSP database; whereas 776 genes related to leukemia were selected using OMIM, GeneCards, and the Therapeutic Target Database. Eight genes common to mylabris and leukemia were identified. Protein-protein interaction network analysis and a component-target-pathway diagram identified TP53 and PTEN as key gene targets of mylabris in the treatment of leukemia. GO enrichment analysis pointed to DNA damage and cell cycle disorder caused by p53 signaling as the most significant processes; whereas KEGG enrichment pointed to the p53 signaling pathway. In summary, mylabris may exert a therapeutic effect on leukemia by triggering DNA damage, inducing apoptosis, as well as inhibiting the growth and proliferation of tumor cells through the regulation of TP53 and PTEN. These findings provide a mechanistic rationale for the treatment of leukemia with traditional Chinese medicine.

Lack of Impact of the A1298C MTHFR on the Risk of Childhood Acute Lymphoblastic Leukemia: Evidence from a Meta-analysis

To clarify the effect of the A1298C variant of methylenetetrahydrofolate reductase (MTHFR) gene on the risk of acute lymphoblastic leukemia (ALL), an updated meta-analysis was performed. Electronic literature search was carried out in PubMed to collect relevant articles. Pooled odds ratios (OR) and stratification analysis were achieved under different genetic comparison models, age and ethnicity. A total of 46 articles including 7020 cases and 12,114 controls were enrolled. Overall, no significant association was observed for the MTHFR A1298C variant on the risk of ALL in any genetic model test, when all the studies pooled together (OR ~ 1 0.91; p > 0.05). In subgroup analyses stratified by age and ethnicity, the MTHFR A1298C reduce the risk of ALL in adult under allele contrast (OR = 0.88; [0.72; 1.09], p = 0.23) mainly in Caucasian populations. The present meta-analysis provides evidence that the A1298C variant of MTHFR gene is unlikely to be a major risk gene for childhood ALL.

Neonatal Leukemia

Neonates are at risk for 3 major forms of leukemia in the first year of life: acute leukemia, juvenile myelomonocytic leukemia, and transient abnormal myelopoiesis associated with Down syndrome. These disorders are rare but generate interest due to aggressive clinical presentation, suboptimal response to current therapies, and fascinating biology. Each can arise as a result of unique constitutional and acquired genetic events. Genetic insights are pointing the way toward novel therapeutic approaches. This article reviews key epidemiologic, clinical, and molecular features of neonatal leukemias, focusing on risk stratification, treatment, and strategies for developing novel molecularly targeted approaches to improve future outcomes.

Association Between Nonsyndromic Cleft Lip and Palate and 2 Polymorphic Loci: A Meta-Analysis

OBJECTIVES

The relationship between Noggin (NOG) and methylenetetrahydrofolate reductase and nonsyndromic cleft lip and palate (NSCLP) has been reported participate in craniofacial development but need further evidence. To indicate the susceptibility between the 2 genes and NSCLP, rs227731 and rs1801131 polymorphisms were included in the present research. This research may provide some genetic clues for disease detection and surveillance.

DESIGN

Seventeen studies including 4023 cases and 5691 controls were provided for meta-analysis, and odds ratio (OR) with 95% CI were obtained to estimate NSCLP risk.

RESULTS

Our analysis suggested potential association of rs227731C on increasing the risk of NSCLP in the Caucasian group and total group but not Asian group under all models: allele (OR = 1.45, 95% CI = 1.21-1.75, P < .0001), homozygote (OR = 2.03, 95% CI = 1.42-2.90, P < .0001), heterozygote (OR = 1.44, 95% CI = 1.19-1.73, P = .0001), dominant (OR = 1.61, 95% CI = 1.27-2.04, P < .0001), and recessive models (OR = 1.63, 95% CI = 1.25-2.12, P = .0003). Besides, increased risk is related to rs1801131 in Asian group under 3 models: allele (OR = 1.24, 95% CI = 1.06-1.44, P = .006), heterozygote (OR = 1.24, 95% CI = 1.02-1.52, P = .03), and dominant models (OR = 1.29, 95% CI = 1.06-1.56, P = .009).

CONCLUSIONS

Our analysis indicates polymorphisms rs227731 and rs1801131 are associated with NSCLP, with predominance of different ethnic group and deepen understanding of NSCLP.

Siblings with ETV6/RUNX1-positive B-lymphoblastic leukemia: A single site experience and review of the literature

Siblings diagnosed with B-lymphoblastic leukemia (B-ALL) that share the same driver abnormality have been rarely described in the literature. Herein, we report three pairs of siblings (one non-identical pair, one maternal half-sibling pair, and one identical pair) all diagnosed with ETV6/RUNX1-positive B-ALL. Considering that ETV6/RUNX1 fusion is thought to represent a prenatal event and necessitates additional genomic alterations to result in leukemia, siblings of patient's with known ETV6/RUNX1-positive B-ALL may be at increased risk of ETV6/RUNX1-positive B-ALL due to common exposures (environmental or infectious) or shared germline polymorphisms.

MTHFR rs1801133 polymorphism is associated with increased risk of B-cell precursor lymphoblastic leukaemia with recurrent genetic aberrations of fetal origin

BACKGROUND

Childhood acute lymphoblastic leukaemia (ALL) is a heterogeneous disease associated with multiple risk factors including genetic susceptibility. Polymorphisms in folate genes have been associated with a protective effect against ALL, although some studies contradict these findings. We aimed to test whether there is an association between the MTHFR rs1801133 variant and the occurrence of B-cell precursor ALL (BCP-ALL) taking in account molecularly distinct subtypes of fetal origin.

METHODS

We performed a case-control genotyping study with 2067 samples, 1309 ALL and 758 controls, from children aged ≤ 15 years for MTHFR rs1801133 polymorphism. Risk associations were calculated by odds ratios estimated with unconditional logistic regression, adjusted for frequency-matched ethnic groups.

RESULTS

Overall, MTHFR rs1801133 does not impact ALL risk in children with more than 6 years of age. A significant positive association for MTHFR rs1801133 variant was found for ALL with KMT2A-r in the dominant model (adj. OR, 1.48, 95 % CI, 1.01-2.17), while ETV6-RUNX1 and Hyperdiploid subgroups have shown a borderline effect (adj. OR, 1.33, 95 % CI, 0.99-1.78).

CONCLUSIONS

The polymorphism MTHFR rs1801133 increased the risk of infant ALL in Brazilian population.

Assessment of the relationship between methylenetetrahydrofolate reductase polymorphism and acute lymphoblastic leukemia: Evidence from an updated meta-analysis

OBJECTIVE

The methylenetetrahydrofolate reductase gene C677T polymorphism is closely related to the acute lymphoblastic leukemia. Several case-control studies have investigated this association; however, no conclusions could be drawn. A comprehensive updated meta-analysis is established to explain these contradictions and clarify the overall impact of this variant on the susceptibility to acute lymphoblastic leukemia.

METHODS

Electronic searches were conducted to select published studies prior to June 2018. Pooled odds ratios and stratification analysis were performed under different genetic comparison models, age, and ethnicity.

RESULTS

Totally, 66 case-control studies including 9619 acute lymphoblastic leukemia cases and 17,396 controls were selected. Our analyses showed that methylenetetrahydrofolate reductase C677T polymorphism was protective mainly in Asian and European countries, under all genetic models and regardless of age, but leukemogenic in mixed population.

CONCLUSION

Thus, C677T polymorphism may be a promising acute lymphoblastic leukemia biomarker, but they should be interpreted with caution considering other factors such as folic acid intake, gene-gene and gene-environment interactions.

Maternal Haplotypes in DHFR Promoter and MTHFR Gene in Tuning Childhood Acute Lymphoblastic Leukemia Onset-Latency: Genetic/Epigenetic Mother/Child Dyad Study (GEMCDS)

Childhood acute lymphoblastic leukemia (ALL) peaks around age 2–4, and in utero genetic epigenetic mother-fetus crosstalk might tune ALL onset during childhood life. Folate genes variably interact with vitamin status on ALL risk and prognosis. We investigated DHFR and MTHFR gene variants in 235 ALL children and their mothers to disclose their role in determining ALL onset age and survival. Pyrosequence of DHFR 19bp ins/del (rs70991108; W/D), MTHFR C677T (rs1801133; C>T), and MTHFR A1298C (rs1801131; A>C) was assessed in children and in 72% of mothers for dyad-analysis comparison. DHFR DD-children had delayed ALL onset compared to WW-children (7.5 ± 4.8 vs. 5.2 ± 3.7 years; P = 0.002) as well as MTHFR 1298 CC-children compared to AA-children (8.03 ± 4.8 vs. 5.78 ± 4.1 years; P = 0.006), and according to the strong linkage disequilibrium between MTHFR 677 T-allele and 1298C-allele, MTHFR TT-children showed early mean age of onset though not significant. Offspring of MTHFR 677 TT-mothers had earlier ALL onset compared to offspring of 677 CC-mothers (5.4 ± 3.3 vs. 7 ± 5.3 years; P = 0.017). DHFR/MTHFR 677 polymorphism combination influenced onset age by comparing DD/CC vs. WW/TT children (8.1 ± 5.7 vs. 4.7 ± 2.1 years; P = 0.017). Moreover, mother-child genotype combination gave 5.5-years delayed onset age in favor of DD-offspring of 677 CC-mothers vs. WW-offspring of 677 TT-mothers, and it was further confirmed including any D-carrier children and any 677 T-carrier mothers (P = 0.00052). Correction for multiple comparisons maintained statistical significance for DHFR ins/del and MTHFR A1298C polymorphisms. Unexpectedly, among the very-early onset group (<2.89 years; 25th), DD-genotype inversely clustered in children and mothers (4.8% vs. 23.8% respectively), and accordingly ALL offspring of homozygous DD-mothers had increased risk to have early-onset (adjusted OR (odds ratio) = 3.08; 1.1–8.6; P = 0.03). The opposite effect DHFR promoter variant has in tuning ALL onset-time depending on who is the carrier (i.e., mother or child) might suggest a parent-origin-effect of the D-allele or a two-faced epigenetic role driven by unbalanced folate isoform availability during the in-utero leukemogenesis responsible for the wide postnatal childhood ALL latency.

Methylenetetrahydrofolate Reductase Gene C677T and A1298C Polymorphic Sequence Variations Influences the Susceptibility to Chronic Myeloid Leukemia in Kashmiri Population

Background: Methylenetetrahydrofolate reductase (MTHFR) gene is a crucial regulator of folate metabolism and its two prominent polymorphic variants C677T and A1298C lead to decreased MTHFR enzyme activity. Aim of the Study: We planned this case-control study based on numerous studies supporting the association of MTHFR polymorphisms (C677T and A1298C) with CML risk in different ethnic populations. Therefore, the influence of these polymorphisms on CML susceptibility was investigated among Kashmiri population (North India). Materials and Methods: Polymerase chain reaction/restriction fragment length polymorphism (RFLP) technique was employed for genotyping MTHFR C677T and A1298C SNP's in 125 CML patients as against 150 age and gender matched healthy controls. Results: A significant difference was observed in frequency of 677CT genotype between cases and controls [46.4 vs. 27.3% (p = 0.0005)]. Similarly combined 677CT+TT genotype showed significant difference between cases and controls [50.4 vs. 28.6% (p = 0.0002)]. Both MTHFR 677CT and 677CT+TT genotypes imposed greater than 2-fold risk of developing CML (OR = 2.4, 95%CI: 1.46-4.05; OR = 2.5, 95%CI: 1.53-4.16). In case of A1298C SNP, the frequency of 1298AC genotype was higher in controls (64.0%) as compared to CML cases (48.8%) (p = 0.04) and imparted a significant protective role from CML predisposition. Furthermore, haplotype analysis revealed only "677CT/1298AA" haplotype significantly increased the risk of CML predisposition [(p = 0.008) (OR = 3.2, 95% CI: 1.3-7.4)]. Conclusion: We conclude that both MTHFR C677T and A1298C polymorphisms may be important genetic modifiers and seem to have a plausible role to confer risk of CML in Kashmiri population, where C677T SNP strongly increases the risk of CML while as A1298C SNP has a protective effect.

How I treat infant leukemia

Leukemia in infants is rare but generates tremendous interest due to its aggressive clinical presentation in a uniquely vulnerable host, its poor response to current therapies, and its fascinating biology. Increasingly, these biological insights are pointing the way toward novel therapeutic approaches. Using representative clinical case presentations, we review the key clinical, pathologic, and epidemiologic features of infant leukemia, including the high frequency of KMT2A gene rearrangements. We describe the current approach to risk-stratified treatment of infant leukemia in the major international cooperative groups. We highlight recent discoveries that elucidate the molecular biology of infant leukemia and suggest novel targeted therapeutic strategies, including modulation of aberrant epigenetic programs, inhibition of signaling pathways, and immunotherapeutics. Finally, we underscore the need for increased global collaboration to translate these discoveries into improved outcomes.

Folic acid, one-carbon metabolism & childhood cancer

Folate has been studied in relation to many diseases, especially cancer. Although it has been postulated to exert a dual effect on development of cancer, its role remains to be clearly defined. Its effect on cancer is the result of gene-nutrient interaction between the genes in folate metabolic pathway and dietary folate availability; mutations in genes of folate metabolism have been shown to alter individual susceptibility to certain childhood cancers as well as response to cancer chemotherapy. Although mandatory fortification of food items with folate has been initiated in some countries, many countries are yet to adopt this due to concerns about undesired adverse effects of high folate levels on health, especially cancer. However, initial reports suggest that folate fortification has led to reduction in incidence of certain childhood cancers such as neuroblastoma, wilms tumour and leukaemias. Despite studies showing folate depletion during antifolate chemotherapy and higher toxicity of chemotherapy in folate-depleted individuals, folate supplementation during cancer chemotherapy is not routinely recommended. Studies investigating the precise effect of folate supplementation during chemotherapy on both short- and long-term outcomes of cancer are needed to arrive at a consensus guideline.

Meta-prediction of MTHFR gene polymorphism-mutations, air pollution, and risks of leukemia among world populations

The major objective of this study was to examine the association between Methylenetetrahydrofolate Reductase (MTHFR) polymorphisms and the risk of various types of leukemias across the lifespans of children and adults by using the meta-predictive techniques. The secondary objective was to examine the interactions among epigenetic risk factors (including air pollution), MTHFR polymorphisms, and the risks of developing leukemia. We completed a comprehensive search of 6 databases to find 54 studies (10,033 leukemia cases and 15,835 controls) for MTHFR 677, and 43 studies (8,868 cases and 14,301 controls) for MTHFR 1298, published from 1999 to 2014. The results revealed that, in European populations; childhood populations; children from Europe, East Asia, and America; and children with acute lymphocytic leukemia (ALL), MTHFR 677 polymorphisms (both TT and CT types together and individually) are protective, while CC wildtype was leukemogenic. In addition, MTHFR 1298 polymorphisms were protective against ALL and acute myeloid leukemia in European children, and in chronic myeloid leukemia in all adults worldwide and American adults. Air pollution played a role in the increased polymorphisms of MTHFR 677 genotypes in childhood leukemia.

MTHFR, TS and XRCC1 genetic variants may affect survival in patients with myelodysplastic syndromes treated with supportive care or azacitidine

We evaluated the impact of genomic polymorphisms in folate-metabolizing, DNA synthesis and DNA repair enzymes on the clinical outcome of 108 patients with myelodysplastic syndromes (MDS) receiving best supportive care (BSC) or azacitidine. A statistically significant association between methylenetetrahydrofolate reductase (MTHFR) 677T/T, thymidylate synthase (TS) 5'-untranslated region (UTR) 3RG, TS 3'-UTR -6 bp/-6 bp, XRCC1 399G/G genotypes and short survival was found in patients receiving BSC by multivariate analysis (P<0.001; P=0.026; P=0.058; P=0.024). MTHFR 677T/T, TS 3'-UTR -6 bp/-6 bp and XRCC1 399G/G genotypes were associated with short survival in patients receiving azacitidine by multivariate analysis (P<0.001; P=0.004; P=0.002). We then performed an exploratory analysis to evaluate the effect of the simultaneous presence of multiple adverse variant genotypes. Interestingly, patients with ⩾1 adverse genetic variants had a short survival, independently from their International Prognostic Scoring System (IPSS) and therapy received. To our knowledge, this is the first study showing that polymorphisms in folate-metabolizing pathway, DNA synthesis and DNA repair genes could influence survival of MDS patients.

Folate metabolism genetic polymorphisms and meningioma and glioma susceptibility in adults

Polymorphic variants of genes involved in folate metabolism are implicated in the susceptibility to meningioma and glioma, but the results from published articles are controversial and inconclusive. Therefore, we performed this meta-analysis including all studies available to evaluate the relationship between folate metabolism genetic polymorphisms and the susceptibility to meningioma and glioma in adults. We searched the literature in PubMed, EMBASE and Cochrane Central Library for relevant articles published up to August 2016. The odds ratios (ORs) and the corresponding 95% confidence intervals (95%Cls) were used to evaluate the associations of two folate metabolism genetic variants MTRR A66G (rs1801394) and MTHFR A1298C (rs1801131) with the risk of meningioma and glioma in adults. We found significant association of MTHFR A1298C (rs1801131) variant genotypes with increased incidence of meningioma and glioma in this study population (CA vs. AA: OR=1.22, P<0.001; CA+CC vs. AA: OR=1.18, P=0.002). Moreover, we found that MTRR A66G (rs1801394) variant genotypes was associated with increased risk of meningioma and glioma (G vs. A: OR=1.11, P=0.020; GG vs. AA+AG: OR=1.17, P=0.043; GG vs. AA: OR=1.22, P=0.023). In conclusion, our meta-analysis suggests that two folate metabolism genetic variants MTRR A66G (rs1801394) and MTHFR A1298C (rs1801131) contribute to genetic susceptibility to meningioma and glioma in adults.

Genotyping the High Altitude Mestizo Ecuadorian Population Affected with Prostate Cancer

Prostate cancer (PC) is the second most commonly diagnosed type of cancer in males with 1,114,072 new cases in 2015. The MTHFR enzyme acts in the folate metabolism, which is essential in methylation and synthesis of nucleic acids. MTHFR C677T alters homocysteine levels and folate assimilation associated with DNA damage. Androgens play essential roles in prostate growth. The SRD5A2 enzyme metabolizes testosterone and the V89L polymorphism reduces in vivo SRD5A2 activity. The androgen receptor gene codes for a three-domain protein that contains two polymorphic trinucleotide repeats (CAG, GGC). Therefore, it is essential to know how PC risk is associated with clinical features and polymorphisms in high altitude Ecuadorian mestizo populations. We analyzed 480 healthy and 326 affected men from our three retrospective case-control studies. We found significant association between MTHFR C/T (odds ratio [OR] = 2.2; P = 0.009), MTHFR C/T+T/T (OR = 2.22; P = 0.009), and PC. The SRD5A2 A49T substitution was associated with higher pTNM stage (OR = 2.88; P = 0.039) and elevated Gleason grade (OR = 3.15; P = 0.004). Additionally, patients with ≤21 CAG repeats have an increased risk of developing PC (OR = 2.99; P < 0.001). In conclusion, genotype polymorphism studies are important to characterize genetic variations in high altitude mestizo populations.

Association of MTHFR C677T and A1298C polymorphisms with oral cancer susceptibility: evidence from a meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) is a central enzyme involved in folate metabolism and plays an important role in DNA synthesis and methylation. Several studies have been conducted to illustrate the associations between MTHFR C677T and A1298C polymorphisms with oral cancer susceptibility; however, the results are inconsistent. Therefore, we conducted an updated meta-analysis to obtain a more reliable estimation of the associations. We retrieved eligible studies from PubMed, EMBASE, and CBM databases through September 2016. Ultimately, pooled analyses involved 10 studies with 1443 cases and 1640 controls for the C677T polymorphism, as well as five studies with 973 cases and 1024 controls for the A1298C polymorphism. Risk estimates were presented as odds ratios (ORs) and 95% confidence intervals (95% CIs). Pooled results indicated that neither C677T nor A1298C polymorphism was associated with oral cancer susceptibility. However, a borderline significant association was detected between MTHFR C677T polymorphism and a decreased oral cancer risk (homozygous model: OR=0.71, 95% CI=0.50–1.00) in hospital-based studies. Our results suggested that MTHFR C677T and A1298C polymorphisms might not be associated with oral cancer risk. However, more evidence is needed to further confirm these findings in the future.

Association of Methylenetetrahydrafolate Reductase Gene Polymorphism (MTHFR) in Patients with Gallbladder Cancer

PURPOSE

5,10-Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism and plays a major role in DNA methylation. There are two popular MTHFR polymorphisms known as C677T and A1298C which are found to be involved in folate metabolism and lowering the enzyme activity, thus may be linked with cancer development. This study aims to look at the association of these polymorphisms in gallbladder cancer.

METHODS

Thirty patients each with gallbladder cancer, cholelithiasis, and normal gallbladder were genotyped for the above-given polymorphisms by PCR-restriction fragment length polymorphism (RFLP) method.

RESULTS

C677T MTHFR polymorphism was not associated (χ(2) = 2.44, p = 0.85) with an increased likelihood of having gallbladder cancer. A1298C was significantly associated (χ(2) = 28.87, p < 0.001) with risk of developing gallbladder cancer. A1298C was significantly correlated with grade (r = 0.337, p < 0.001) and histopathology (r = 0.446, p < 0.001).

CONCLUSION

This study proposed that MTHFR A1298C polymorphism may be associated with risk of developing gallbladder cancer, and there is no association between C677T polymorphism and gallbladder cancer.

Involvement of MTHFR and TPMT genes in susceptibility to childhood acute lymphoblastic leukemia (ALL) in Mexicans

BACKGROUND

Folate metabolism plays an essential role in the processes of DNA synthesis and methylation. Deviations in the folate flux resulting from single-nucleotide polymorphisms in genes encoding folate-dependent enzymes may affect the susceptibility to leukemia. This case-control study aimed to assess associations among MTHFR (C677T, A1298C) and TPMT (*2, *3A) mutations as well as to evaluate the synergistic effects of combined genotypes for both genes. Therefore, these genetic variants may lead to childhood acute lymphoblastic leukemia (ALL) susceptibility, in a Mexican population study.

METHODS

DNA samples obtained from 70 children with ALL and 152 age-matched controls (range, 1-15 years) were analyzed by real-time reverse transcription polymerase chain reaction (RT-qPCR) to detect MTHFR C677T and A1298C and TPMT*2 and TPMT*3A genotypes.

RESULTS

The frequency of the MTHFR A1298C CC genotype was statistically significant (odds ratio [OR], 6.48; 95% 95% confidence intervals [CI], 1.26-33.2; p=0.025). In addition, the combined 677CC+1298AC genotype exhibited a statistically significant result (OR, 0.23; 95% CI, 0.06-0.82; p=0.023). No significant results were obtained from the MTHFR (C677T CT, C677T TT) or TPMT (*2, *3A) genotypes. More importantly, no association between the synergistic effects of either gene (MTHFR and/or TPMT) and susceptibility to ALL was found.

CONCLUSIONS

The MTHFR A1298C CC genotype was associated with an increased risk of developing childhood ALL. However, a decreased risk to ALL with the combination of MTHFR 677CC+1298AC genotypes was found.

Unique Familial MLL(KMT2A)-Rearranged Precursor B-Cell Infant Acute Lymphoblastic Leukemia in Non-twin Siblings

BACKGROUND

Infant acute lymphoblastic leukemia (ALL) has never occurred in families except for the ∼100% concordant cases in monozygous twins attributed to twin-to-twin metastases. We report the first kindred with infant ALL in non-twin siblings. The siblings were diagnosed with MLL-rearranged (MLL-R) ALL 26 months apart. The second affected sibling had an unaffected dichorionic monozygous co-twin. Both had fatal outcomes.

PROCEDURES

Translocations were characterized by karyotype, FISH, multiplex FISH, and MLL breakpoint cluster region (bcr) Southern blot analysis. Breakpoint junctions and fusion transcripts were cloned by PCR. TP53 mutation and NADPH quinone oxidorecuctase 1 (NQO1) C609T analyses were performed, and pedigree history and parental occupations were ascertained. The likelihood of chance occurrence of infant ALL in non-twin siblings was computed based on a binomial distribution. Zygosity was determined by single nucleotide polymorphism (SNP) array.

RESULTS

The translocations were not related or vertically transmitted. The complex karyotype of the proband's ALL had chromosome 2, 3, 4, and 11 abnormalities causing a 5'-MLL-AFF1-3' fusion and a non-productive rearrangement of 3'MLL with a chromosome 3q intergenic region. The affected twin's ALL exhibited a simple t(4;11). The complex karyotype of the proband's ALL suggested a genotoxic insult, but no exposure was identified. There was no germline TP53 mutation. The NQO1 C609T risk allele was absent. The likelihood of infant ALL occurring in non-twin siblings by chance alone is one in 1.198 × 10(9) families.

CONCLUSIONS

Whether because of a deleterious transplacental exposure, novel predisposition syndrome, or exceedingly rare chance occurrence, MLL-R infant ALL can occur in non-twin siblings. The discordant occurrence of infant ALL in the monozygous twins was likely because they were dichorionic.

Association between Methylenetetrahydrofolate Reductase (MTHFR) Gene Polymorphisms and Susceptibility to Childhood Acute Lymphoblastic Leukemia in an Iranian Population

BACKGROUND

The present study was aimed to examine the possible association between methylene tetrahydrofolate reductase (MTHFR) gene polymorphisms and childhood acute lymphoblastic leukemia (ALL) in a sample of Iranian population.

SUBJECTS AND METHODS

A total of 220 subjects including 100 children diagnosed with ALL and 120 healthy children participated in the case-control study. The single nucleotide polymorphisms (SNPs) of MTHFR were determined by ARMS-PCR or PCR-RFLP method.

RESULTS

Our investigation revealed that rs13306561 both TC and TC + CC genotypes decreased the risk of ALL compared to TT genotype (OR=0.32, 95%CI=0.15-0.68, p=0.002 and OR=0.35, 95%CI=0.17-0.70, p=0.003, respectively). In addition, the rs13306561 C allele decreased the risk of ALL in comparison with T allele (OR=0.42, 95% CI=0.22-0.78, P=0.005). MTHFR rs1801131 (A1298C) polymorphism showed that the AC heterozygous genotype decreased the risk of ALL in comparison with AA homozygous genotype (OR=0.43, 95%CI=0.21-0.90, p=0.037). Neither the overall Chi-square comparison of cases and control subjects (𝜒2=5.54, p=0.063) nor the logistic regression analysis showed significant association between C677T polymorphism and ALL (OR=1.25, 95% CI=0.69-2.23, p=0.552; CT vs. CC).

CONCLUSION

The current investigation findings showed that MTHFR rs1801131 and rs13306561 polymorphisms decreased the risk of ALL in the population which has been studied. Further studies with larger sample sizes and different ethnicities are required to validate our findings.

Functional variants of gene encoding folate metabolizing enzyme and methotrexate-related toxicity in children with acute lymphoblastic leukemia

Methotrexate (MTX) is commonly used agent in therapy of malignancies, including acute lymphoblastic leukemia (ALL). Based on the literature data it is known that MTX elimination and toxicity can be affected by polymorphisms in genes encoding enzymes involved in MTX metabolism. The aim of our study was to investigate the influence of C677T and A1298C polymorphisms in methylenetetrahydrofolate reductase (MTHFR) gene on MTX-induced toxicity during treatment of children with ALL. We also tried to answer the question whether simultaneous occurrence of these two polymorphisms has a clinical significance. MTHFR polymorphisms were assessed in 47 pediatric ALL patients, treated according to intensive chemotherapy for childhood ALL, ALL IC BFM 2009. Prolonged MTX elimination and higher incidence of toxicity were observed for patients with 677T-1298A haplotype. On the other hand, occurrence of 677C-1298A haplotype had protective effect on MTX clearance and toxicity, that was not observed in carriers of 677C-1298C haplotype. In patients with coexistence of studied variants 677CT/1298AC heterozygotes as well as in 677TT/1298AA homozygotes more frequently toxicity incidents were noted. The obtained results suggest that occurrence of 677T allele and coexistence of 677T and 1298C alleles may be associated with lower MTX clearance and elevated risk of adverse effects during MTX-treatment of pediatric ALL patients.

Maternal supplementation with folic acid and other vitamins and risk of leukemia in offspring: a Childhood Leukemia International Consortium study

BACKGROUND

Maternal prenatal supplementation with folic acid and other vitamins has been inconsistently associated with a reduced risk of childhood acute lymphoblastic leukemia (ALL). Little is known regarding the association with acute myeloid leukemia (AML), a rarer subtype.

METHODS

We obtained original data on prenatal use of folic acid and vitamins from 12 case-control studies participating in the Childhood Leukemia International Consortium (enrollment period: 1980-2012), including 6,963 cases of ALL, 585 cases of AML, and 11,635 controls. Logistic regression was used to estimate pooled odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for child's age, sex, ethnicity, parental education, and study center.

RESULTS

Maternal supplements taken any time before conception or during pregnancy were associated with a reduced risk of childhood ALL; odds ratios were 0.85 (95% CI = 0.78-0.92) for vitamin use and 0.80 (0.71-0.89) for folic acid use. The reduced risk was more pronounced in children whose parents' education was below the highest category. The analyses for AML led to somewhat unstable estimates; ORs were 0.92 (0.75-1.14) and 0.68 (0.48-0.96) for prenatal vitamins and folic acid, respectively. There was no strong evidence that risks of either types of leukemia varied by period of supplementation (preconception, pregnancy, or trimester).

CONCLUSIONS

Our results, based on the largest number of childhood leukemia cases to date, suggest that maternal prenatal use of vitamins and folic acid reduces the risk of both ALL and AML and that the observed association with ALL varied by parental education, a surrogate for lifestyle and sociodemographic characteristics.

The association of methylenetetrahydrofolate reductase genotypes with the risk of childhood leukemia in Taiwan

Background

Acute 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 Findings

In 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).

Conclusions

Our 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.

MTHFR gene polymorphism in acute lymphoblastic leukemia among North Indian children: a case-control study and meta-analysis updated from 2011

Studies on the association of methylenetetrahydrofolate reductase (MTHFR) genotype in childhood acute lymphoblastic leukemia (ALL) have yielded conflicting results. The present study examines this association in north Indian children with ALL and includes an updated meta-analysis. MTHFR (677 and 1298) genotype of children with ALL and healthy adult controls were done by the PCR-restriction fragment length polymorphism (PCR-RFLP) method and were compared using various models of inheritance. A total of 150 patients and 300 controls were included. The 677T allele was found protective (odds ratio (OR) 0.21, 95% confidence interval (CI) 0.04-0.94), whereas 1298C allele led to an increase in risk (OR 4.44, 95% CI 2.19-8.99) of childhood ALL. Meta-analysis included 31 and 27 studies examining the association of 677 and 1298 genotypes, respectively. The 677 C -> T polymorphism was protective (OR 0.90, 95% CI 0.82-0.99). Protection was more pronounced in folate-sufficient populations as compared with those not covered by folate fortification guidelines. The 1298A->C polymorphism was associated with a marginal increase in risk (OR 1.19, 95% CI 1.01-1.40).

MTHFR promotes heterochromatin maintenance

Methylenetetrahydrofolate reductase (MTHFR), a key enzyme in the folate cycle, catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a co-substrate for homocysteine remethylation to methionine. Methionine serves as the precursor of the active methyl donor S-adenosylmethionine, which provides methyl groups for many biological methylations. It has been reported that MTHFR is highly phosphorylated under unperturbed conditions and T34 is the priming phosphorylation site. In this report, we generated a phospho-specific antibody that recognized T34-phosphorylated form of MTHFR and revealed that MTHFR was phosphorylated at T34 in vivo and this phosphorylation peaked during mitosis. We further demonstrated that the cyclin-dependent kinase 1 (CDK1)/Cyclin B1 complex is the kinase that mediates MTHFR phosphorylation at T34 and the MTHFR immunocomplex purified from mitotic cells exhibited lower enzymatic activity. Inhibition of MTHFR expression resulted in a decrease of H3K9me3 levels, and an increase of transcription of the centromeric heterochromatin markers. Taken together, our results demonstrated that CDK1/Cyclin B1 phosphorylates MTHFR on T34 and MTHFR plays a role in the heterochromatin maintenance at the centromeric region.

The methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and tumor risk: evidence from 134 case-control studies

Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism, which is essential for DNA synthesis and methylation. Genetic variations in the MTHFR gene seem to contribute to a decreased activity of MTHFR, ultimately confer increased susceptibility to cancer. As the most extensively studied polymorphism, MTHFR C677T polymorphism was shown to contribute to cancer susceptibility but the results were inconsistent. The authors performed a meta-analysis including 134 studies (46,207 cases and 69,160 controls) to address the issue. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to assess the association. Overall, a significant elevated risk of cancer was associated with the MTHFR C677T polymorphism in T-allele versus C-allele comparison (OR = 1.06, 95% CI 1.02-1.11, P(heterogeneity) < 0.001), homozygote model (OR = 1.08, 95% CI 1.01-1.17, P(heterogeneity) < 0.001) and dominant model (OR = 1.05, 95% CI 1.00-1.10, P(heterogeneity) < 0.001). In the stratified analyses, significantly increased cancer risks were indicated among Asians in all genetic models except for heterozygote model. Further analysis revealed that C677T was significantly associated with an increased risk of esophageal and stomach cancer. This meta-analysis supports an association between the MTHFR C677T polymorphism and increased risk of esophageal and stomach cancer, especially among Asians. Additionally, more high-quality studies and that the covariates responsible for heterogeneity should be controlled to obtain a more conclusive response about the function of MTHFR C677T in cancer.

MTHFR A1298C and C677T gene polymorphisms and susceptibility to chronic myeloid leukemia in Egypt

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the intracellular folate metabolism which plays an important role in carcinogenesis through DNA methylation. We aimed to evaluate the association between MTHFR A1298C and C677T polymorphisms and the risks of chronic myeloid leukemia (CML). Eighty-five patients with CML and a control group containing 100 healthy, age and sex matched individuals were examined for MTHFR C677T and A1298C polymorphisms using polymerase chain reaction-restriction fragment-length (PCR-RFLP) method. The frequency of 677TT genotype in patients with CML was significantly higher compared to controls (OR=2.513, 95% CI: 0.722-4.086, P=0.025). No such association was shown for heterozygous 677CT (OR=1.010, 95% CI: 0.460-2.218, P=0.981). Moreover, for A1298C genotype, a statistically significant higher frequency of 1298CC was also detected in CML patients compared to control group (OR=1.1816, 95% CI: 0.952-3.573, P=0.036), 0.036). No such statistical significance was demonstrable for heterozygote 1298AC (OR=1.046, 95% CI: 0.740-1.759, P=0.092). In addition, patients with joint 677CT/1298AC or 677TT/1298CC genotypes showed an association with increased risk of CML (OR=1.849, 95% CI: 0.935-2.540, P=0.024; OR=1.915, 95% CI: 1.202-3.845, P=0.020 respectively). .A statistically significant increased risk of resistant to therapy was observed with 677CT and 1298AC genotypes (P=0.001, P=0.002 respectively). We conclude that both MTHFR 677TT and 1298CC polymorphisms have been associated with risk of CML and both 677CT and 1298AC genotypes are associated with higher risk of resistant to therapy.

MTHFR C677T polymorphism: association with lymphoid neoplasm and effect on methotrexate therapy

The aim of this study was to detect the possible role of methylene tetrahydrofolate reductase gene polymorphism (MTHFR C677T) in the pathogenesis of lymphoid neoplasms and to investigate the influence of this polymorphism on methotrexate toxicity in adult ALL patients treated with methotrexate maintenance therapy. There was a statistically significant increase in the risk of non-Hodgkin lymphoma in patients with CT genotype (OR, 2.9; 95% CI, 1.3-6.3; P = 0.007) and combined CT + TT genotype (OR, 3.2; 95% CI, 1.5-6.6; P = 0.006). While no significant association was found between this polymorphism and ALL risk. The patients with ALL treated with methotrexate during maintenance therapy were observed for signs of toxicity. MTHFR 677C>T polymorphism (CT + TT) was significantly overrepresented among cases with hepatic toxicity (OR = 15.6; 95% CI, 2.6-81.3; P = 0.001). In addition, they were overrepresented among cases with mucositis, anemia, thrombocytopenia, and leukopenia. However, it did not reach statistical significance level. Further studies on larger number of subjects are necessary. Additional studies on the role of MTHFR gene polymorphism with environment (folate intake) interaction are needed to confirm the role of these genetic polymorphisms.

ARID5B polymorphism confers an increased risk to acquire specific MLL rearrangements in early childhood leukemia

BACKGROUND

Acute leukemia in early age (EAL) is characterized by acquired genetic alterations such as MLL rearrangements (MLL-r). The aim of this case-controlled study was to investigate whether single nucleotide polymorphisms (SNPs) of IKZF1, ARID5B, and CEBPE could be related to the onset of EAL cases (<24 months-old at diagnosis).

METHODS

The SNPs (IKZF1 rs11978267, ARID5B rs10821936 and rs10994982, CEBPE rs2239633) were genotyped in 265 cases [169 acute lymphoblastic leukemia (ALL) and 96 acute myeloid leukaemia (AML)] and 505 controls by Taqman allelic discrimination assay. Logistic regression was used to evaluate the association between SNPs of cases and controls, adjusted on skin color and/or age. The risk was determined by calculating odds ratios (ORs) with 95% confidence interval (CI).

RESULTS

Children with the IKZF1 SNP had an increased risk of developing MLL-germline ALL in white children. The heterozygous/mutant genotype in ARID5B rs10994982 significantly increased the risk for MLL-germline leukemia in white and non-white children (OR 2.60, 95% CI: 1.09-6.18 and OR 3.55, 95% CI: 1.57-8.68, respectively). The heterozygous genotype in ARID5B rs10821936 increased the risk for MLL-r leukemia in both white and non-white (OR 2.06, 95% CI: 1.12-3.79 and OR 2.36, 95% CI: 1.09-5.10, respectively). Furthermore, ARID5B rs10821936 conferred increased risk for MLL-MLLT3 positive cases (OR 7.10, 95% CI:1.54-32.68). Our data do not show evidence that CEBPE rs2239633 confers increased genetic susceptibility to EAL.

CONCLUSIONS

IKZF1 and CEBPE variants seem to play a minor role in genetic susceptibility to EAL, while ARID5B rs10821936 increased the risk of MLL-MLLT3. This result shows that genetic susceptibility could be associated with the differences regarding MLL breakpoints and partner genes.

Genetic polymorphisms in MTHFR (C677T, A1298C), MTR (A2756G) and MTRR (A66G) genes associated with pathological characteristics of prostate cancer in the Ecuadorian population

INTRODUCTION

The methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and MTR reductase (MTRR) enzymes act in the folate metabolism, which is essential in methylation and synthesis of nucleic acids. The single nucleotide polymorphisms, MTHFR C677T, A1298C, MTR A2756G and MTRR A66G, cause alteration in the homocysteine levels and reduced enzymatic activity that generates deficiency in the assimilation of folates associated with DNA damage; that is, why it is important to know if the single nucleotide polymorphisms are associated with the pathological characteristics and development of prostate cancer, through a case-control retrospective study.

METHODS

DNA was extracted from 110 healthy and 104 affected men. The genotypes were determined by means of the polymerase chain reaction-restriction fragment length polymorphism and confirmed with genomic sequencing.

RESULTS

We found significant association between the genotypes of the MTHFR C677T polymorphism: C/T (odds ratio [OR] = 2.2; 95% confidence interval [CI] = 1.3-3.9; P = 0.008) and C/T + T/T (OR = 2.2; 95% CI = 1.3-3.9; P = 0.009) with the risk of prostate cancer development, and a slight association with MTRR A66G. Regarding pathological characteristics, we found significant risk between the C/T + T/T genotypes and the Gleason score (7-10) of poorly differentiated carcinoma (OR = 5.2; 95% CI = 1.7-16.2; P = 0.007). On the other hand, a significant association between A1298C, A66G, and A2756G with the pathological characteristics was not found (P > 0.05).

CONCLUSIONS

The MTHFR C677T polymorphism has significant effects on susceptibility to prostate cancer in Ecuadorian population, especially with the Gleason grade.

MTHFR Gene Polymorphisms and the Risk of Acute Lymphoblastic Leukemia in Adults and Children: A Case Control Study in India

Genetic polymorphisms in the methylene tetrahydrofolate reductase (MTHFR) gene have been associated with the development of acute leukemias and various malignancies. The role of MTHFR polymorphism in the development of pediatric acute lymphoblastic leukemia (ALL) has been extensively studied among north Indians in various settings, yet its association with acute leukemias remains unresolved. To evaluate the relationship between functional MTHFR polymorphisms, C677T and A1298C and possible effect on risk of ALL in adults and children in North Indian population by comparing them with healthy controls. DNA was isolated from peripheral blood of 184 ALL patients (33 adults, 151 children) and 155 controls and analyzed by a PCR-restriction fragment length polymorphism assay. The frequency of MTHFR 677CT and 1298 AC genotypes were significantly lower among adult ALL cases when compared to the controls. We found a 1.74-fold reduced risk of ALL in individuals with 1298AC polymorphic variant and a 9.17-fold decreased risk of adult ALL. However, no statistically significant difference was evident between the above polymorphisms and susceptibility to ALL in children. Polymorphisms in the MTHFR gene possibly modulate risk of ALL in north Indian adults but not in children, although larger studies are needed.

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

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

C677T polymorphism of methylenetetrahydrofolate reductase may contribute to cervical cancer risk in complete over-dominant model

PURPOSE

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate. The single nucleotide polymorphism (SNP), C677T (Ala>Val, rs1801133), has been confirmed to decrease the enzyme activity. The association between C677T and cervical cancer susceptibility has been widely studied. However, the results were inconsistent. In order to elucidate the role of this SNP in cervical cancer, a meta-analysis was conducted.

METHODS

The literature search was performed using the following databases: PubMed, Embase and ISI Web of Science up to December 2012. The effect of association was indicated as crude odds ratio (OR) with the corresponding 95% confidence interval (CI).

RESULTS

Six studies including 1431 cases and 1915 controls explored C677T genotypes were involved in this meta-analysis. Overall meta-analysis showed that C677T polymorphism increased cervical cancer risk in the complete over-dominant model (random-effect OR=1.33, 95% CI: 1.00-1.77, I(2)=69%). After excluding one study which showed apparent heterogeneity, the heterogeneity disappeared. The meta-analysis of five studies including 1231 cases and 1715 controls showed the fixed-effect OR reached 1.20 (95% CI: 1.03-1.40, I(2)=0) as (TT+CC) in the complete over-dominant model.

CONCLUSIONS

C677T polymorphism of MTHFR gene may increase the risk of cervical cancer in the complete over-dominant model. The association merits replicating and validating in further studies.

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms and promoter methylation in cervical oncogenic lesions and cancer

The aim of this study was to investigate the role of methylenetetrahydrofolate reductase (MTHFR) polymorphisms and MTHFR methylation pattern in cervical lesions development among women from Romania, a country with high prevalence of human papillomavirus (HPV) cervical infections. To achieve this goal, blood samples and cervical cytology specimens (n = 77)/tumour tissue specimens (n = 23) were investigated. As control, blood and negative cytological smears (n = 50) were used. A statistically significant association was found between T allele of C677T polymorphism and cervical lesions, heterozygote women presenting a threefold increased risk (normal/cervical lesions and tumours: wild homozygote 34/41 (0.68/0.41), heterozygote 14/51 (0.28/0.51), mutant homozygote 2/8 (0.04/0.08); OR = 3.081, P = 0.0035). Using χ square test for the control group, the HPV-negative and HPV-positive patients with cervix lesions, a significant correlation between viral infection and T allele of C677T polymorphism (P = 0.0287) was found. The MTHFR promoter was methylated in all HGSIL and tumour samples, significant differences being noted between HPV-positive samples, control group and cases of cervical dysplastic lesions without HPV DNA (P < 0. 0001) and between samples from patients with high-risk (hr)HPV versus low-risk (lr)HPV (P = 0.0026). No correlations between polymorphisms and methylation were observed. In Romania, individuals carrying T allele are susceptible for cervical lesions. MTHFR promoter methylation is associated with cervical severity lesions and with hrHPV.

Genetic variants modify susceptibility to leukemia in infants: a Children's Oncology Group report

BACKGROUND

The mixed lineage leukemia (MLL) gene is commonly rearranged in infant leukemia (IL). Genetic determinants of susceptibility to IL are unknown. Recent genome-wide association studies for childhood acute lymphoblastic leukemia (ALL) have identified susceptibility loci at IKZF1, ARID5B, and CEBPE.

PROCEDURE

We genotyped these loci in 171 infants with leukemia and 384 controls and evaluated associations overall, by subtype [ALL, acute myeloid leukemia (AML)], and by presence (+) or absence (-) of MLL rearrangements.

RESULTS

Homozygosity for a variant IKZF1 allele (rs11978267) increased risk of infant AML [Odds ratio (OR) = 3.9, 95% confidence interval (CI) = 1.8-8.4]; the increased risk was similar for AML/MLL+ and MLL- cases. In contrast, risk of ALL/MLL- was increased in infants homozygous for the IKZF1 variant (OR = 5.1, 95% CI = 1.8-14.5) but the variant did not modify risk of ALL/MLL+. For ARID5B (rs10821936), homozygosity for the variant allele increased risk for the ALL/MLL- subgroup only (OR = 7.2, 95% CI = 2.5-20.6). There was little evidence of an association with the CEBP variant (rs2239633).

CONCLUSION

IKZF1 is expressed in early hematopoiesis, including precursor myeloid cells. Our data provide the first evidence that IKZF1 modifies susceptibility to infant AML, irrespective of MLL rearrangements, and could provide important new etiologic insights into this rare and heterogeneous hematopoietic malignancy.