MTHFD1 G1958A Research Articles

Association of MTHFD1 G1958A, MTHFD1 T401C and CBS 844ins68bp with Breast Cancer in Jordan

MTHFD1 and CBS genes have key roles in folate and homocysteine metabolism. Many studies reported an association between cancer pathogenesis and different functional SNPs of genes involved in the main folate metabolism and the transsulfuration pathway. The current population-based, case-control study examined the association between MTHFD1 G1958A, MTHFD1 T401C, and the CBS 844ins68 insertion with breast cancer (BC) risk in Jordanian women. The studied population included 200 female BC subjects and age-matched female controls. The targeted genotypes MTHFD1 G1958A and MTHFD1 T401C were amplified via PCR followed by subsequent digestion with the proper restriction enzyme (PCR-RFLP), while the insertion/deletion of CBS844ins68bp was visualized and scored directly after gel electrophoresis. Results showed that the examined individual alleles and genotypes of MTHFD 1958A, MTHFD1 401C, and CBS844ins68bp per se were not associated with risk of BC compared with their wild-type genotypes and alleles.

Association Between Multiple Single Nucleotide Polymorphisms in Folate Metabolism Pathway and Breast Cancer Risk in Georgian Women: A Case-Control Study.

The folate metabolism pathway plays an integral part in DNA synthesis, methylation, and repair. Methylenetetrahydrofolate reductase (MTHFR) and methylenetetrahydrofolate dehydrogenase (MTHFD1) are both enzymes that are involved in this pathway, and the single nucleotide polymorphisms (SNPs) in genes coding for them have modulatory effects on DNA expression. This study aimed to investigate the relationship between MTHFR C677T (rs1801133) and MTHFD1 G1958A (rs2236225) polymorphisms and the risk of developing breast cancer in Georgian women. A case-control study was performed examining the MTHFR C677T and MTHFD1 G1958A SNP in breast cancer-confirmed cases and healthy matched controls. Real time-polymerase chain reaction (PCR) was used to genotype SNPs. The case individuals' pathology reports were obtained following surgeries for cancer characteristic data. Statistical analysis was performed to investigate the significance of the acquired data. Statistical analysis of MTHFR C677T SNP revealed that the CT genotype increased the risk of breast cancer by 2.17 folds in the over-dominant model. Statistical analysis of MTHFD1 G1958A SNP showed that the GA genotype increased the risk of breast cancer by 4.12 folds in the codominant model and 2.41 folds in the over-dominant model. No statistically significant link was found between genotypes and lymph node status, however, patients with the CT genotype had higher percentages of proliferative activity. Breast cancer seems to have a statistically significant association with the CT genotype in MTHFR C677T and the GA genotype in MTHFD1 G1958A in Georgian women.

The negative effect of G1958A polymorphism on MTHFD1 protein stability and HCC growth.

Methylenetetrahydrofolate dehydrogenase (MTHFD1), a key enzyme on the folate pathway, has been implicated in the tumor development of distinct types of cancers. The single nucleotide polymorphism (SNP) of 1958G > A mutation in the coding region of MTHFD1 (arginine 653 is mutated into glutamine) has been detected in a significant proportion of clinical samples of hepatocellular carcinoma (HCC). METHODS : Hepatoma cell lines, 97H and Hep3B were used. The expression of MTHFD1 and SNP mutation protein was determined by immunoblotting analysis. The protein ubiquitination of MTHFD1 was detected by immunoprecipitation analysis. The post-translational modification sites and interacting proteins of MTHFD1 in the presence of G1958A SNP were identified by mass spectrometry. Metabolic flux analysis was used to detect the synthesis of relevant metabolites sourced from serine isotope. The present study showed G1958A SNP of MTHFD1, encoding MTHFD1 R653Q, was associated with the attenuated protein stability caused by ubiquitination-mediated protein degradation. Mechanistically, MTHFD1 R653Q displayed an enhanced binding to the E3 ligase TRIM21, which was responsible for the augmented ubiquitination, and MTHFD1 K504 was identified to be the primary ubiquitination site. The subsequent metabolite analysis revealed MTHFD1 R653Q resulted in the repressed flux of serine-derived methyl group into metabolite precursors for purine synthesis, and the compromised purine synthesis was demonstrated to be responsible for the impeded growth capability in MTHFD1 R653Q-expressing cells. Moreover, the suppressive effect of MTHFD1 R653Q expression in tumorigenesis was verified by xenograft analysis, and the relationship between MTHFD1 G1958A SNP and its protein levels was revealed in clinical human liver cancer specimens. Our results uncovered an unidentified mechanism underlying of the impact of G1958A SNP on MTHFD1 protein stability and tumor metabolism in HCC. which provides a molecular basis for the according clinical management when considering MTHFD1 as a therapeutic target.

Relationship of MTHFD1 G1958A and CBS 844ins68 polymorphism with congenital heart defects in North Indian population (Jammu and Kashmir): A case-control study

Objectives: There are many multifactorial causes for Congenital Heart Defects (CHDs) in which both genetic and non-genetic factors play role. MTHFD1 and CBS are two of the key enzymes that plays pivotal role in the metabolic pathway of homocysteine. Most of the studies revealed that genes involved in folate/homocysteine pathways are involved in the occurrence of CHDs. The present study was planned to investigate the role of common polymorphisms in MTHFD1 and CBS gene in children with CHD in Jammu region of Jammu and Kashmir UT. Material and Methods: A total of 160 (80 CHD patients and 80 controls) children were enrolled for the present case-control study. After extraction of genomic DNA genotyping of SNP MTHFD1 G1958A(rs2236225) was done by PCR-RFLP and CBS 844ins68 polymorphism was done by PCR technique. Results: Our results show that there is no significant association between MTHFD1G1958A and CBS 844ins68 polymorphism with CHD. In case of SNP MTHFD1 G1958A allele A found to be higher in both patient and control group and inCBS 844ins68 polymorphism frequency of risk allele ‘I’ found higher in cases (0.06) as compared to controls (0.04). The homozygous genotype for 844ins68 (II) was found absent in both the patients and control group. Conclusion: We conclude that both MTHFD1 G1958A and CBS 844ins68 polymorphism were not found to be genetic risk factor in the development of CHD in population of Jammu region of Jammu and Kashmir UT.

Maternal folate, one-carbon metabolism and pregnancy outcomes.

Single nucleotide polymorphisms and pre‐ and peri‐conception folic acid (FA) supplementation and dietary data were used to identify one‐carbon metabolic factors associated with pregnancy outcomes in 3196 nulliparous women. In 325 participants, we also measured circulating folate, vitamin B12 and homocysteine. Pregnancy outcomes included preeclampsia (PE), gestational hypertension (GHT), small for gestational age (SGA), spontaneous preterm birth (sPTB) and gestational diabetes mellitus (GDM). Study findings show that maternal genotype MTHFR A1298C(CC) was associated with increased risk for PE, whereas TCN2 C766G(GG) had a reduced risk for sPTB. Paternal MTHFR A1298C(CC) and MTHFD1 G1958A(AA) genotypes were associated with reduced risk for sPTB, whereas MTHFR C677T(CT) genotype had an increased risk for GHT. FA supplementation was associated with higher serum folate and vitamin B12 concentrations, reduced uterine artery resistance index and increased birth weight. Women who supplemented with <800 μg daily FA at 15‐week gestation had a higher incidence of PE (10.3%) compared with women who did not supplement (6.1%) or who supplemented with ≥800 μg (5.4%) (P < .0001). Higher serum folate levels were found in women who later developed GDM compared with women with uncomplicated pregnancies (Mean ± SD: 37.6 ± 8 nmol L−1 vs. 31.9 ± 11.2, P = .007). Fast food consumption was associated with increased risk for developing GDM, whereas low consumption of green leafy vegetables and fruit were independent risk factors for SGA and GDM and sPTB and SGA, respectively. In conclusion, maternal and paternal genotypes, together with maternal circulating folate and homocysteine concentrations, and pre‐ and early‐pregnancy dietary factors, are independent risk factors for pregnancy complications.

Formate concentrations in maternal plasma during pregnancy and in cord blood in a cohort of pregnant Canadian women: relations to genetic polymorphisms and plasma metabolites

One-carbon metabolism, responsible for purine and thymidylate synthesis and transmethylation reactions, plays a critical role in embryonic and fetal development. Formate is a key player in one-carbon metabolism. In contrast to other one-carbon metabolites, it is not linked to tetrahydrofolate, is present in plasma at appreciable concentrations, and may therefore be distributed to different tissues. The study was designed to determine the concentration of formate in cord blood in comparison with maternal blood taken earlier in pregnancy and at delivery and to relate formate concentrations to potential precursors and key fetal genotypes. Formate and amino acids were measured in plasma during early pregnancy (12-16 wk), at delivery (37-42 wk), and in cord blood samples from 215 mothers, of a prospective cohort study. Three fetal genetic variants in one-carbon metabolism were assessed for their association with cord plasma concentrations of formate. The formate concentration was ∼60% higher in the cord blood samples than in mothers' plasma. The maternal formate concentrations did not differ between the early pregnancy samples and those taken at delivery. Plasma concentrations of 4 formate precursors (serine, glycine, tryptophan, and methionine) were increased in cord blood compared with the maternal samples. Cord blood formate was influenced by fetal genotype, being ∼12% higher in infants harboring the MTHFR A1298C (rs1801131) AC or CC genotypes and 10% lower in infants harboring the MTHFD1 G1958A (rs2236225) GA or AA genotypes. The increased formate concentrations in cord blood may support the increased activity of one-carbon metabolism in infants. As such, it would support increased rates of purine and thymidylate synthesis and the provision of methionine for methylation reactions.

Analysis of polymorphisms in genes involved in folate metabolism and its impact on Down syndrome and other intellectual disability

Folate is one of the B vitamins and essential for cellular functioning because it donates one‑carbon for de novo purine and pyrimidine synthesis, required for DNA synthesis and repair. Deficiency or mutation in one of the cofactor or enzyme involved in folate/homocysteine metabolism may leads to DNA hypomethylation, abnormal DNA synthesis, DNA strand breakage, impaired DNA repair and neurological damages as well as abnormal chromosomal segregation and chromosomal breaks. MTR, MTHFD1 and CBS are the key enzymes involved in the folate/homocysteine metabolism. The present study analyzed the risk association of MTR A2756G, MTHFD1 G1958A and CBS 844ins68 in the Down syndrome and other intellectually disabled children from Gujarat, using PCR/PCR-RFLP technique. The results of the present study revealed the significant association between MTR A2756G polymorphism and risk for intellectual disability. The significant negative associations were observed among MTR A2756G or MTHFD1 G1958A polymorphisms and Down syndrome. The CBS ins+/ins+ genotype showed 4.09 fold increased risk of intellectual disability.

Relationship of the MTHFD1 (rs2236225), eNOS (rs1799983), CBS (rs2850144) and ACE (rs4343) gene polymorphisms in a population of Iranian pediatric patients with congenital heart defects

Congenital heart defects are structural cardiovascular malformations that arise from abnormal formation of the heart or major blood vessels during the fetal period. To investigate the association of 4 single nucleotide polymorphisms (SNPs) in the MTHFD1, eNOS, CBS and ACE genes, we evaluated their relationship with CHD in Iranian patients. In this case–control study, a total of 102 children with CHD and 98 control children were enrolled. Four SNPs including MTHFD1 G1958A, eNOS G894T, CBS C-4673G and ACE A2350G were genotyped by PCR-SSCP, Multiplex ARMS PCR and PCR-RFLP methods and confirmed by direct sequencing. We genotyped 102 patients and 98 controls for four polymorphisms by statistically analysis. There were three SNPs including MTHFD1 G1958A, eNOS G894T and ACE A2350G which might increase the risk of CHD, but CBS C-4673G was not significantly different between patients and controls. (P = 0.017, P = 0.048, P = 0.025 and P = 0.081 respectively). The allele frequencies of three SNPs for MTHFD1 G1958A, eNOS G894T and ACE A2350G in CHD are higher than that in control. Our results show that there is a significant relationship between MTHFD1 G1958A, eNOS G894T and ACE A2350G polymorphisms with CHD. Therefore, The AA and GA genotypes of MTHFD1 G1958A, TT and GT genotypes of eNOS G894T and the AA and GA genotypes of ACE A2350G are susceptible factors for CHD and may increase the risk of CHD.

P113: The protective effect of G1958A SNP on the MTHFD1 gene in susceptibility to non-Hodgkin malignant lymphomas

Background Methylation systems in the cells play an important role in the metabolic processes such as purine nucleotide biosynthesis and gene and protein activity regulation. An imbalance between entities in folic acid metabolism can adversely affect nucleotide synthesis and the DNA repair and methylation system, which can cause genome instability and impairments in chromosome segregation, and lead to abnormal expression of proto-oncogenes and inactivation of tumor suppressor genes. These processes may underlie the development of a range of cancer disease, including Non-Hodgkin’s lymphomas (NHL). Quite a few studies investigating the association of SNPs in the folate-metabolizing genes with NHL risk in populations of different ethnic origin are available to date. Because the low prevalence of this disease makes sampling difficult, most of these studies have small sizes, which may be one of the reasons why results obtained are often conflicting. The aim of this study was to investigate the role of some SNPs in folate genes (the C677T and A1298C SNPs in the MTHFR gene, A2756G in MTR, A66G in SHMT1, G1958A in MTHFD1 and 844ins68 in CBS) in genetic susceptibility to non-Hodgkin’s malignant lymphoma in the west-Siberian region. Methods 146 unrelated patients from the Haematological Center (Novosibirsk city) with various types of NHL were investigated. Genomic DNA was isolated from leukocytes in venous blood and from buccal epithelium, using the standard methods of DNA separation. A PCR-restriction fragment length polymorphism (RFLP) assay was used to detect the MTHFD1 G1958A and CBS 844ins68 SNPs. Genotyping of the MTHFR, MTR, MTRR and SHMT1 gene SNPs was carried out by real-time PCR allelic discrimination with TaqMan probes. The alleles and genotypes distribution of SNPs in patients were compared with their distribution in healthy white Russian subjects from Novosibirsk. Results We determined the allele and genotype frequencies for seven SNPs in folate metabolism in NHL and control groups. For all these SNPs, the genotype frequencies were in Hardy–Weinberg equilibrium in the control group. There were no statistically significant differences in the frequencies of alleles and genotypes of polymorphic loci of MTHFR, MTRR, CBS, SHMT1 genes between patients with NHL and controls. However, theG1958A MTHFD1 polymorphism showed a significant association with aggressive NHL. The 1958A allele (OR = 0.578, C.I. [0.415–0.805], p p Conclusion G1958A SNP in the MTHFD1 gene contributes to susceptibility to NHL. The mutant allele and genotype determine the protective effect, probably, by affecting the concentration of intracellular folic acid metabolites.

Paternal transmission of MTHFD1 G1958A variant predisposes to neural tube defects in the offspring.

This study aimed to evaluate the role of methylenetetrahydrofolate dehydrogenase (MTHFD1) G1958A variant (rs2236225) as a 'maternal, paternal, or embryonic' genetic risk factor for neural tube defect (NTD) susceptibility. It also estimated differential associations based on type of NTD, offspring sex, maternal-paternal-offspring genotype incompatibility, and parent-of-origin effects (POE) using both case-control and family-based approach. In addition, genotype impact on serum folate levels was also assessed. The study population (n=900) consisted of 120 NTD case-parent triads (n=120×3=360) and 180 healthy control-parent triads (n=180×3=540) from South India. Umbilical cord tissues were collected from those with NTD and control newborn infants, and blood samples from case and control parents. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. Statistical analysis used were SPSS, transmission disequilibrium test and POE. Serum folate levels were estimated using enzyme-linked immunosorbent assay. In the case-control study, those with the MTHFD1 G1958A variant were associated with around twofold risk of anencephaly (p=0.01) and spina bifida (p<0.01). Among parents, fathers were associated with around twofold risk of having an offspring with anencephaly (p<0.01). Considering offspring sex, the A allele in single or double dose conferred around two- to fourfold risk of anencephaly (p=0.01), spina bifida (p<0.01), and encephalocele (p<0.05) in females only. Maternal AA genotype was not associated independently but conferred threefold risk when combined with paternal GA genotype (p=0.01). Transmission disequilibrium and POE were not observed in controls (p>0.05) but revealed excess total (odds ratio [OR]=2.21; p<0.01) and paternal transmission (OR=7.00; p<0.01) of the G1958A allele to those with spina bifida, which remained the same for female cases (total transmission OR=3.00, p=0.01; paternal transmission OR=12.00, p<0.01). Increased serum folate levels were observed in case fathers with GA and AA genotypes than control fathers (p<0.01). Our research provides the first evidence supporting a paternal, rather than a maternal, transmission bias of MTHFD1 G1958A variant for NTD susceptibility in the offspring.

Geographical and ethnic distribution of single nucleotide polymorphisms within genes of the folate/homocysteine pathway metabolism.

High levels of plasma homocysteine are associated with an increased risk of many health conditions influenced by both environmental and genetic factors. The objective of this study was to provide the geographical distribution of folate pathway genetic polymorphisms in Mexico and the comparison with the reported frequencies in different continental populations. This study included the analysis of the genotypic frequencies of eight polymorphisms in genes of the folate/homocysteine metabolic pathway in 1,350 Mestizo and Amerindian subjects from different regions in Mexico and 836 individuals from European, African and Asian populations of the 1,000 Genomes Project. In Mexican Mestizo and Amerindian populations, the MTHFR C677T risk genotype (TT) was highly prevalent (frequency: 25 and 57 %, respectively). In Mestizos, the frequency showed clear regional variation related to ancestry; the Guerrero subpopulation with the highest Amerindian contribution had the highest TT frequency (33 %). The MTHFD1 G1958A AA risk genotype was also enriched in Mexican Mestizos and Amerindians (frequency: 34 and 58 %, respectively), whereas in African and Asian ancestry populations the frequency for AA was low (~4 %). All together risk genotypes showed regional differences, and Sonora had significantly different genetic frequencies compared with the other regions (P value <0.05). Our study illustrates differential geographical distribution of the risk variants in the folate/homocysteine metabolic pathway relative to ethnic background. This work supports that certain areas of the world have increased needs for folic acid and vitamin B supplementation, and this information needs to be considered in public health guidelines and eventually policies.Electronic supplementary materialThe online version of this article (doi:10.1007/s12263-014-0421-7) contains supplementary material, which is available to authorized users.

Association between MTHFD1 G1958A polymorphism and neural tube defects susceptibility: a meta-analysis.

ObjectivesThe methylenetetrahydrofolate dehydrogenase (MTHFD1) gene, as one of the key genes involved in the folate pathway, has been reported to play a critical role in the pathogenesis of neural tube defects (NTDs). However, the results of published studies are contradictory and inconclusive. Thus, this meta-analysis aimed to evaluate the effect of the common polymorphism in the MTHFD1 gene, the G1958A (R653Q, dbSNP ID: rs2236225) variant, on the risk of NTDs in all eligible studies.MethodsRelevant literature published before January 3, 2014 was retrieved from the MEDLINE, EMBASE, Cochrane Library, and CBM databases. Pooled crude odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated to evaluate the association between the MTHFD1 G1958A polymorphism and NTDs risk.ResultsWe performed a meta-analysis of nine studies with a total of 4,302 NTDs patients and 4,238 healthy controls. Our results demonstrated a significant correlation between the MTHFD1 G1958A polymorphism and NTDs in an overall meta-analysis. For family-based studies, the study subjects were classified as NTD cases, mothers with NTDs offspring, and fathers with NTDs offspring. We found no association between any of the fathers’ genotypes and NTDs, whereas there was a clear excess of the 1958A allele in the mothers of children with NTDs compared with controls individuals.ConclusionsIn summary, our meta-analysis strongly suggests that the MTHFD1 G1958A polymorphism might be associated with maternal risk for NTDs in Caucasian populations. However, the evidence of this association should be interpreted with caution due to the selective nature of publication of genetic association studies.

Choline metabolism biomarkers predict the risk of metabolic unfitness among young men

To test the hypothesis that plasma choline metabolism biomarkers, alone and together with genetic determinants of one carbon (1‐C) metabolism, predict metabolic unfitness associated with a lipid overload (i.e. obesity), a cross‐sectional analysis was conducted involving 249 Mexican American men with a median age of 22 y. Circulating concentrations of choline, betaine, folate, metabolic unfitness indicators (i.e. lipid panel and liver enzymes), and polymorphisms of 1‐C metabolizing genes (i.e. MTHFD1 G1958A) were assessed. Bivariate partial correlation tests and multivariate regression models were performed in data analysis. Plasma choline positively and plasma betaine negatively associated with body mass index (BMI) with lower plasma betaine observed in men whose BMI &gt; 25.8 kg/m2 (cohort median). In age‐ and BMI‐adjusted regression models, plasma betaine associated positively with serum HDL‐cholesterol. Further, plasma betaine associated negatively with serum alanine aminotransferase (ALT) among men with serum folate &lt; 14.5 ng/mL (cohort median) or among men with at least one copy of MTHFD1 1958A allele. In sum, these data demonstrate that choline metabolism markers predict the risk of metabolic unfitness and support the need to investigate the potential therapeutic benefits of choline/betaine on metabolic fitness.Grant Funding Source : NIH Grant #S06GM053933 and California Agriculture Research Initiative

Investigation of Homocysteine-Pathway-Related Variants in Essential Hypertension

Hyperhomocysteinemia (hHcy) has been associated with an increased risk of cardiovascular disease and stroke. Essential hypertension (EH), a polygenic condition, has also been associated with increased risk of cardiovascular related disorders. To investigate the role of the homocysteine (Hcy) metabolism pathway in hypertension we conducted a case-control association study of Hcy pathway gene variants in a cohort of Caucasian hypertensives and age- and sex-matched normotensives. We genotyped two polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR C677T and MTHFR A1298C), one polymorphism in the methionine synthase reductase gene (MTRR A66G), and one polymorphism in the methylenetetrahydrofolate dehydrogenase 1 gene (MTHFD1 G1958A) and assessed their association with hypertension using chi-square analysis. We also performed a multifactor dimensionality reduction (MDR) analysis to investigate any potential epistatic interactions among the four polymorphisms and EH. None of the four polymorphisms was significantly associated with EH and although we found a moderate synergistic interaction between MTHFR A1298C and MTRR A66G, the association of the interaction model with EH was not statistically significant (P = 0.2367). Our findings therefore suggest no individual or interactive association between four prominent Hcy pathway markers and EH.

Association between 11 genetic polymorphisms in folate-metabolising genes and head and neck cancer risk

Genetic polymorphisms in folate metabolism may affect the risk of head and neck cancer (HNSCC) due to its involvement in DNA methylation and synthesis. We conducted a case-control study (265 HNSCC cases and 466 non-cancer controls) to investigate associations of MTHFR C677T and A1298C, MTR A2756G, MTRR A66G, RFC1 A80G, MTHFD1 G1958A, CBS 844ins68, TC2 C776G and A67G, SHMT C1420T and BHMT G742A polymorphisms with HNSCC risk. Interactions between polymorphisms and survival time, tobacco and alcohol habits, age, gender and tumour staging (TNM classification) were evaluated by multiple logistic regression analysis. We found that age ⩾49years (P<0.001), male gender (P=0.03), tobacco habit (P<0.001), MTHFR 1298AC/CC (P=0.028), MTR 2756AG/GG (P=0.010) and RFC1 80AG/GG (P=0.015) genotypes were associated with an increased risk of HNSCC. There were interactions between lower survival and CBS 844ins68 (P=0.005); age ⩾49years and MTR 2756 AG/GG (P=0.004) and RFC1 80AG/GG (P=0.006) genotypes; male gender and MTHFR 1298 AC/CC (P=0.030), MTR 2756 AG/GG (P=0.006) and RFC1 80 AG/GG (P=0.009); tobacco non-habit and MTHFD1 1958GA/AA (P=0.040); tobacco and MTHFR 1298 AC/CC (P=0.054) and MTR 2756 AG/GG (P=0.010); alcohol non-consume and RFC1 80 AG/GG (P=0.008) with HNSCC increased risk. MTHFR C677CT/TT genotypes were less frequently in advanced tumours (P=0.04). In conclusion, our data provide evidence that folate metabolism genetic polymorphisms associated with variables as advanced age, male gender, tobacco and alcohol increase HNSCC development; CBS 844ins68 and MTHFR C677T polymorphisms are associated with less survival time and advanced stage tumours, respectively.

MTHFD1 G1958A, BHMT G742A, TC2 C776G and TC2 A67G polymorphisms and head and neck squamous cell carcinoma risk

Alterations in folate metabolism may contribute to the process of carcinogenesis by influencing DNA methylation and genomic stability. Polymorphisms in genes encoding enzymes involved in this pathway may alter enzyme activity and consequently interfere in concentrations of homocysteine and S-adenosylmethionine that are important for DNA synthesis and cellular methylation reactions. The objectives were to investigate MTHFD1 G1958A, BHMT G742A, TC2 C776G and TC2 A67G polymorphisms involved in folate metabolism on head and neck cancer risk and the association between these polymorphisms with risk factors. Polymorphisms were investigated in 762 individuals (272 patients and 490 controls) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Real Time-PCR. Chi-square and Multiple logistic regression were used for the statistical analysis. Multiple logistic regression showed that tobacco and male gender were predictors for the disease (P < 0.05). Hardy-Weinberg equilibrium showed that the genotypic distributions were in equilibrium for both groups in all polymorphisms studied. The BHMT 742GA or AA genotypes associated with tobacco consumption (P = 0.016) increase the risk for head and neck squamous cell carcinoma (HNSCC). The present study suggests that BHMT 742GA polymorphism associated to tobacco modulate HNSCC risk. However, further investigation of gene-gene interactions in folate metabolism and studies in different populations are needed to investigate polymorphisms and HNSCC risk.

Carcinogênese de cabeça e pescoço: impacto do polimorfismo MTHFD1 G1958A

OBJECTIVE: To investigate the MTHFD1 G1958A polymorphism involved in the folate metabolism as a risk for head and neck cancer, and to find the association of the polymorphism with the risk factors and clinical and histopathological characteristics. METHODS: Retrospective study investigating MTHFD1 G1958A polymorphism in 694 subjects (240 patients in the Case Group and 454 in the Control Group) by Restriction Fragment Length Polymorphism (RFLP) Analysis. Multiple logistic regression and chi-square tests were used in the statistical analysis. RESULTS: Multivariable analysis showed that smoking and age over 42 years were disease predictors (p < 0.05). MTHFD1 1958GA or AA genotypes were associated with smoking (p = 0.04) and alcoholism (p = 0.03) and were more often found in more advanced stage tumors (p = 0.04) and in patients with a shorter survival (p = 0.03). CONCLUSION: The presence of MTHFD1 G1948A polymorphism associated with smoking and alcoholism raises the head and neck cancer risk.

Head and neck carcinogenesis: impact of MTHFD1 G1958A polymorphism

To investigate the MTHFD1 G1958A polymorphism involved in the folate metabolism as a risk for head and neck cancer, and to find the association of the polymorphism with the risk factors and clinical and histopathological characteristics. Retrospective study investigating MTHFD1 G1958A polymorphism in 694 subjects (240 patients in the Case Group and 454 in the Control Group) by Restriction Fragment Length Polymorphism (RFLP) Analysis. Multiple logistic regression and chi-square tests were used in the statistical analysis. Multivariable analysis showed that smoking and age over 42 years were disease predictors (p < 0.05). MTHFD1 1958GA or AA genotypes were associated with smoking (p = 0.04) and alcoholism (p = 0.03) and were more often found in more advanced stage tumors (p = 0.04) and in patients with a shorter survival (p = 0.03). The presence of MTHFD1 G1948A polymorphism associated with smoking and alcoholism raises the head and neck cancer risk.

Head and neck carcinogenesis: impact of MTHFD1 G1958A polymorphism

Head and neck carcinogenesis: impact of MTHFD1 G1958A polymorphism

Polymorphisms in folate-metabolizing genes and risk of non-Hodgkin's lymphoma

We investigated the role of single nucleotide polymorphisms (SNPs) in the folate-metabolizing genes MTHFR, MTR, MTRR, MTHFD, CBS and SHMT in regulating genetic susceptibility to Non-Hodgkin's lymphoma (NHL). We determined the allele and genotype frequencies in the case group (146 patients with NHL) and the control group (540 blood donors). A significant association with NHL was observed only for MTHFD1 G1958A (allele G OR = 1.382, P = 0.05; genotype GA OR = 2.316, P = 0.01; genotype GG OR = 2.153, P = 0.03). After additional stratification of case and control groups according to sex and tumor type association of MTHFD1 G1958A with NHL was observed only in high-grade NHL subgroup (allele G OR = 1.664, P = 0.01) and in women subgroup (allele G OR = 2.043, P = 0.009). Meta-analysis for SNPs in the MTHFR, MTR, MTRR and SHMT revealed a reducing effect of the MTR 2756G allele on the risk of NHL (OR = 0.902; 95% CI 0.821–0.991, P = 0.03).