Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.5.7.1 (methylenetetrahydrofolate reductase)
2,116 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphisms of the genes 5'-10'-methylenetetrahydrofolate reductase (MTHFR, 677CT and 1298AC), methionine synthase (MTR, 2756AC) and methionine synthase reductase (MTRR, 66AC) provoke variations in enzyme activity, which can lead to alterations in the metabolism of folates and in the synthesis of S-adenosyl-methionine (SAM), the most active methyl donor in the body. This could play an important role in carcinogenesis through the degree of DNA methylation and of nucleotide synthesis. In the present study, four polymorphisms were studied, two of the methylenetetrahydrofolate reductase gene, and the other two of methionine synthase and methionine synthase reductase. Our aim was to study the association between prostate carcinoma susceptibility and these polymorphisms. A hospital-based case-control study was conducted in 182 patients (mean age: 70.7+/-7.29 years) with histologically confirmed prostate carcinoma and in 205 control subjects (mean age: 70.3+/-7.82 years) diagnosed with benign prostatic hyperplasia (BPH). Genomic DNA was extracted from peripheral leukocytes. Comparison of the MTHFR CT and TT genotypes in patients and the controls revealed significant differences (0.57 vs 0.38) (OR: 2.19, 95% CI: 1.46-3.30) and (0.06 vs 0.15) (OR: 0.36, 95% CI: 0.17-0.73), respectively. No statistically significant differences were found between patients and controls with respect to the MTHFR 1298AC, the MTR 2756AC and the MTRR 66AC polymorphisms. However, among the patients, the MTR 2756 allele C was related to a high Gleason score. We conclude that the polymorphism MTHFR C677T is clearly related to prostatic carcinogenesis, on the contrary to the other polymorphisms studied, although the MTR 2756 allele C acts as a factor of tumor aggressiveness, this being found in tumors with high carcinogenic potential.
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PMID:Association between polymorphisms of folate-metabolizing enzymes and risk of prostate cancer. 1796 24

Individuals with Down syndrome (DS) present decreased homocysteine (Hcy) concentration, reflecting a functional folate deficiency secondary to overexpression of the cystathionine ss-synthase gene. Since plasma Hcy may be influenced by genetic polymorphisms, we evaluated the influence of C677T and A1298C polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR), of A2756G polymorphism in the methionine synthase gene (MTR), and of A80G polymorphism in the reduced folate carrier 1 gene on Hcy concentrations in Brazilian DS patients. Fifty-six individuals with free trisomy 21 were included in the study. Plasma Hcy concentrations were measured by liquid chromatography_tandem mass spectrometry with linear regression coefficient r(2) = 0.9996, average recovery between 92.3 to 108.3% and quantification limits of 1.0 micromol/L. Hcy concentrations >15 micromol/L were considered to characterize hyperhomocystinemia. Genotyping for the polymorphisms was carried out by polymerase chain reaction followed by enzyme digestion and allele-specific polymerase chain reaction. The mean Hcy concentration was 5.2 +/- 3.3 micromol/L. There was no correlation between Hcy concentrations and age, gender or MTHFR C677T, A1298C and reduced folate carrier 1 A80G genotype. However, Hcy concentrations were significantly increased in the MTR 2756AG heterozygous genotype compared to the MTR 2756AA wild-type genotype. The present results suggest that the heterozygous genotype MTR 2756AG is associated with the increase in plasma Hcy concentrations in this group of Brazilian patients with DS.
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PMID:The MTR A2756G polymorphism is associated with an increase of plasma homocysteine concentration in Brazilian individuals with Down syndrome. 1806 Mar 20

Environmental exposures and/or genetic background in Japanese population, which might contribute to the relatively low breast cancer incidence rates in Japan, have not been clarified in detail. Folate plays an essential role in DNA methylation and synthesis, and thus may be involved in the development of breast cancer. Functional polymorphisms in genes encoding one-carbon metabolism enzymes, methylenetetrahydrofolate reductase (MTHFR C677T), methionine synthase (MTR A2756G), methionine synthase reductase (MTRR A66G) and thymidylate synthase (TS), influence folate metabolism, but epidemiological studies have yielded inconsistent findings. We therefore conducted a case-control study to clarify their associations with breast cancer risk. A total of 456 breast cancer cases and 912 age-matched and menopausal status-matched non-cancer controls were genotyped for the polymorphisms. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using conditional logistic models adjusted for potential confounders and gene-environment interactions between the polymorphisms and folate consumption were also evaluated. We observed an increased risk of postmenopausal breast cancer with the MTHFR 677TT genotype (OR = 1.83, 95% CI: 1.08-3.11) with a menopausal status-based analysis. In combination analysis, a significantly elevated OR was found among postmenopausal women with the MTHFR 677TT genotype and lower intake of dietary folate compared with those with 677CC genotype and adequate folate consumption (OR = 2.80, 95% CI: 1.11-7.07). In addition, interaction between the MTRR A66G polymorphism and folate intake for risk of postmenopausal breast cancer was observed (interaction P = 0.008). Our findings indicated that the MTHFR and MTRR polymorphisms were associated with individual susceptibility to breast cancer among postmenopausal women.
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PMID:One-carbon metabolism-related gene polymorphisms and risk of breast cancer. 1817 36

High-resolution melting (HRM) shows great promise for high-throughput, rapid genotyping of individual polymorphic loci. We have developed HRM assays for genotyping single nucleotide polymorphisms (SNP) in several key genes that are involved in methyl metabolism and may directly or indirectly affect the methylation status of the DNA. The SNPs are in the 5,10-methylenetetrahydrofolate reductase (MTHFR; C677T and A1298C), methionine synthetase (MTR; 5-methyltetrahydrofolate-homocysteine methyltransferase; A2756G), and DNA methyltransferase 3b (DNMT3b; C46359T and C31721T) loci. The choice of short amplicons led to greater melting temperature (Tm) differences between the two homozygous genotypes, which allowed accurate genotyping without the use of probes or spiking with control DNA. In the case of MTHFR, there is a second rarer SNP (rs4846051) close to the A1298C SNP that may result in inaccurate genotyping. We masked this second SNP by placing the primer over it and choosing a base at the polymorphic position that was equally mismatched to both alleles. The HRM assays were done on HRM capable real-time PCR machines rather than stand-alone HRM machines. Monitoring the amplification allows ready identification of samples that may give rise to aberrant melting curves because of PCR abnormalities. We show that samples amplifying markedly late can give rise to shifted melting curves without alteration of shapes and potentially lead to misclassification of genotypes. In conclusion, rapid and high-throughput SNP analysis can be done with probe-free HRM if sufficient attention is paid to amplicon design and quality control to omit aberrantly amplifying samples.
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PMID:Direct genotyping of single nucleotide polymorphisms in methyl metabolism genes using probe-free high-resolution melting analysis. 1848 46

Effect of alcohol consumption on pancreatic cancer risk has been investigated in many studies, but results have been inconsistent. We conducted a case-control study to assess the effect of alcohol on pancreatic cancer in conjunction with polymorphisms in one-carbon metabolism enzymes, methylenetetrahydrofolate reductase (MTHFR C677T), methionine synthase (MTR A2756G), methionine synthase reductase (MTRR A66G), and thymidylate synthase (TS) variable number of tandem repeat. A total of 157 pancreatic cancer patients and 785 age- and sex- matched control subjects were genotyped for polymorphisms. Odds ratios (OR) with 95% confidence intervals (95% CI) were estimated using unconditional logistic models adjusted for potential confounders. Heavy alcohol drinking was marginally associated with an increased risk of pancreatic cancer (OR, 1.90; 95% CI, 1.00-3.62). None of the polymorphisms showed any significant effect on pancreatic cancer risk by genotype alone. In stratified analysis, effect of alcohol consumption on pancreatic cancer was observed in individuals with the MTHFR 667 CC, MTR 2756 AA, or MTRR 66 G allele. OR (95% CI) of pancreatic cancer for heavy drinkers compared with never drinkers was 4.50 (1.44-14.05) in the MTHFR 667 CC genotype, 2.65 (1.17-6.00) in the MTR 2756 AA genotype, and 3.35 (1.34-8.36) in the MTRR 66 G allele carriers. These results suggest that the folate-related enzyme polymorphism modifies the association between drinking habit and pancreatic cancer risk.
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PMID:Alcohol drinking and one-carbon metabolism-related gene polymorphisms on pancreatic cancer risk. 1884 18

We analyzed the role of six common polymorphisms in folate metabolizing genes as possible risk factors for having a child with Down syndrome (DS) in 94 Italian mothers of a DS child (MDS) and 113 matched control mothers, both aged less than 35 years at conception. Investigated polymorphisms include methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C, methionine synthase (MTR) 2756A>G, methionine synthase reductase (MTRR) 66A>G, and thymidylate synthase (TYMS) 28bp repeat and 1494del6. We also measured the amount of chromosome damage in peripheral blood lymphocytes of 42 MDS and 41 matched controls, by means of the micronucleus assay, and searched for association between this cytogenetic endpoint and any of the studied polymorphisms. Micronuclei in peripheral blood lymphocytes have been analyzed several years after conception: the mean age at sampling was 45.6+/-11.4 years for MDS and 47.95+/-6.9 years for controls. The combined MTHFR 677TT/MTR 2756AA genotype was associated with increased DS risk (P=0.034), and the combined MTHFR 1298AC/TYMS 2R/2R genotype with reduced risk (P=0.003). Moreover, we observed a significant increased frequency of micronucleated lymphocytes in MDS as compared to controls (P<0.0001) and, in the total population, a significant correlation between micronucleated cells and both MTHFR 677C>T (P=0.031) and 1298A>C (P=0.047) polymorphisms.
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PMID:Association of maternal polymorphisms in folate metabolizing genes with chromosome damage and risk of Down syndrome offspring. 1898 96

Aberrant promoter methylation is recognized as an important feature of breast carcinogenesis. We hypothesized that genetic variation of genes for methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MTR), two critical enzymes in the one-carbon metabolism, may alter DNA methylation levels and thus influence DNA methylation in breast cancer. We evaluated case-control association of MTHFR C677T, A1298C, and MTR A2756G polymorphisms for cases strata-defined by promoter methylation status for each of three genes, E-cadherin, p16, and RAR-beta2 in breast cancer; in addition, we evaluated case-case comparisons of the likelihood of promoter methylation in relation to genotypes using a population-based case-control study conducted in Western New York State. Methylation was evaluated with real-time methylation-specific PCRs for 803 paraffin-embedded breast tumor tissues from women with primary, incident breast cancer. We applied unordered polytomous regression and unconditional logistic regression to derive adjusted odds ratios and 95% confidence intervals. We did not find any association of MTHFR and MTR polymorphisms with breast cancer risk stratified by methylation status nor between polymorphisms and likelihood of promoter methylation of any of the genes. There was no evidence of difference within strata defined by menopausal status, estrogen receptor status, folate intake, and lifetime alcohol consumption. Overall, we found no evidence that these common polymorphisms of the MTHFR and MTR genes are associated with promoter methylation of E-cadherin, p16, and RAR-beta2 genes in breast cancer.
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PMID:DNA promoter methylation in breast tumors: no association with genetic polymorphisms in MTHFR and MTR. 1924 Feb 36

Carcinogenesis may result from abnormal methylation of cancer-related genes regulatory sequence. Though, the polymorphic variants of genes encoding enzymes of folate and methionine metabolism may have an effect on DNA methylation. Using PCR-RFLPs, we examined the polymorphism distribution of genes encoding methionine synthase (MTR); 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase (MTHFD1); and methylenetetrahydrofolate reductase (MTHFR) in patients with larynx cancer (n = 131) and controls (n = 250). Patients with MTR 2756AG or GG genotypes displayed a 1.856 -fold increased risk of larynx cancer (95% CI = 1.1860-2.903, P = 0.0076). However, we did not observe an increased risk for the homozygous GG genotype OR = 1.960 (95% CI = 0.6722-5.713, P = 0.2535). Moreover, we did not observe statistical differences in distribution of MTHFR 677C>T, 1298A>C and MTHFD1 1958G>A allele and genotype frequencies in patients and controls. Our findings confirm the significance of the role of the methyl cycle in etiopathogenesis of laryngeal cancer.
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PMID:Polymorphic variants of folate metabolism genes and the risk of laryngeal cancer. 1964 27

The purpose of the study was to investigate the association between cervical cancer risk and single-nucleotide polymorphisms (SNPs) in three one-carbon metabolism genes, methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and methionine synthase reductase (MTRR) in Korean women. Twelve SNPs were identified in MTHFR, MTR, and MTRR in the 927 case-control samples, which included 165 cervical intraepithelial neoplasia 1 (CIN1), 167 cervical intraepithelial neoplasia 2 and 3 (CIN2/3), 155 cervical cancer patients, and 440 normal controls. The frequencies of the genotypes and haplotypes were assessed in the controls, CINs, and cervical cancers. Individual carriers of the variant allele C of MTHFR A1298C (rs1801131) had a 0.64-fold [95% confidence interval (CI): 0.42-0.98] decreased risk for CIN2/3 compared with common homozygotes. However, no significant association was found between most other variants and cervical cancer risk. The results also identified an increased CIN1 risk in carriers with at least one copy of haplotype 3 in the MTHFR gene (odds ratio, 1.88; 95% CI: 1.03-3.42). In conclusion, there was no significant association between most SNPs in MTHFR, MTR, or MTRR and the risk of CIN and cervical cancer in Korean women. In addition, there was no significant association of MTHFR haplotypes with risk of CIN2/3 and cervical cancer.
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PMID:The effects of polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR), and methionine synthase reductase (MTRR) on the risk of cervical intraepithelial neoplasia and cervical cancer in Korean women. 1976 26

Cigarette smoking is the most important risk factor for bladder cancer. Moreover, epidemiologic studies have implicated several genetic variations interfering with methyl group metabolisms in susceptibility for a variety of cancers. Examples of these variations can be found in genes of the folate metabolic pathway, which is crucial in the provision of methyl groups for DNA, RNA, and protein methylation, as well as in purine and pyrimidine synthesis. We conducted a case-control study to examine the relationship between the methylenetetrahydrofolate reductase (MTHFR C677 T and MTHFR A1298C), methionine synthase (5-methyltetrahydrofolate-homocysteine methyltransferase, MTR A2756 G), methionine synthase reductase (5-methyltetrahydrofolate-homocysteine methyltransferase reductase, MTRR A66 G and MTRR C524 T), and thymidylate synthase (TYMS 2R-->3R and G/C) genotypes and the risk for bladder cancer in a Tunisian population. The isolated MTHFR 677 *T, MTRR 66 *G and MTRR 524 *T variants did not appear to influence bladder cancer susceptibility. The 3R *C/3R *C genotype for the TYMS gene appears to be a protective factor against bladder cancer development (P=0.0001; OR=0.12; 95% CI=0.03-0.40). However, patients heterozygous for MTHFR A1298C or MTR A2756 G genotypes have 1.62- and 2.13-fold higher risk, respectively, of developing bladder cancer. Moreover, the combined study of MTHFR 1298 *C and MTR 2756 *G variants with either or both MTRR 66GG and TYMS 3R *G/3R *G genotypes suggests a cumulative effect. Finally, this study evidenced that interaction between gene variations involved in folate metabolism and risk of bladder cancer increased dramatically among smokers.
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PMID:Polymorphisms in one-carbon metabolism pathway genes and risk for bladder cancer in a Tunisian population. 1983 68


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