Methylenetetrahydrofolate Reductase A1298C Polymorphism and Breast Cancer Risk: A Meta-analysis of 33 Studies

Distribution of Methionine Synthase Reductase (MTRR) Gene A66G Polymorphism in Indian Population

Methionine synthase reductase (MTRR) is an important enzyme of the folate/homocysteine pathway. It is responsible for regulation of methionine enzyme by reductive methylation. A common variant A66G is reported in the FMN-binding domain of the MTRR gene, which leads to substitution of isoleucine by methionine (I22M) in MTRR enzyme with reduced activity. Reduced catalytic activity of enzyme leads to high homocysteine concentration in blood and increases risk for numerous diseases. The frequency of A66G polymorphism varies in different ethnic groups. The present study has been designed to evaluate the frequency of MTRR A66G gene polymorphism in the Eastern UP population by PCR-RFLP method. Along with this we also performed a meta-analysis to evaluate the global prevalence of this polymorphism. Databases were screened to identified the eligible studies. The prevalence of the G allele and GG genotype was determined by the use of prevalence proportion with 95% CI. Open meta-analyst software was used for the meta-analysis. Total 1000 blood samples were analyzed, the frequencies of A and G alleles were 0.35 and 0.65 respectively. Meta-analysis results revealed that the prevalence of G allele and GG genotype were 49.4% (95% CI 40.6-58.1, p ≤ 0.001) and 24.3% (95% CI 17.8-30.9, p ≤ 0.001) respectively. In sub-group meta-analysis, the lowest frequency of G allele was found in South America (32.7%; 95% CI 14.1-51.3, p ≤ 0.001), and highest in Asia (56.4%; 95% CI 39.5-73.3, p ≤ 0.001). The results of the meta-analysis showed that the Asian population has the highest frequency of G allele and highest frequency of the GG genotype was found in the European population.

Association of C677T (rs1081133) and A1298C (rs1801131) Methylenetetrahydrofolate Reductase Variants with Breast Cancer Susceptibility Among Asians: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis were conducted to investigate the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms with breast cancer (BC) in Asians. Systematic searches were conducted in PubMed, EMBASE, Web of Science, and Scopus by May 2020. Inter-study heterogeneity was also assessed with a Q test, along with I² statistics. Random-effects models were applied to pooled crude ORs with corresponding 95% CIs for the genetic models. A total of 1097 identified results, along with 36 qualified studies were included: for MTHFR C677T polymorphism, a total of 36 studies was comprised of 11,261 cases and 13,318 controls and for MTHFR A1298C polymorphism, a number of 19 studies contained 7424 cases and 8204 controls. Likewise, for C677T polymorphism, an increased risk of BC was seen for the allelic (OR 1.21, 95% CI 1.09-1.33, P < 0.01, I² = 78.9%), dominant (OR 1.17, 95% CI 1.05-1.30, P < 0.01, I² = 71.8%), recessive (OR 1.43, 95% CI 1.23-1.67, P < 0.01, I² = 55.8%), and homozygous models (OR 1.48, 95% CI 1.25-1.75, P < 0.01, I² 59.9%) among BC patients compared to controls. Also, in terms of A1298C polymorphism, an association was found between the allelic (OR 1.15, 95% CI 1.04-1.28, P < 0.01, I² 70.4%) and homozygous models (OR 1.38, 95% CI 1.15-1.66, P < 0.01, I² 44.2%) with the risk of BC. In conclusion, findings revealed that MTHFR C677T variant might be a factor that predisposes BC in Asians. Furthermore, it was found that A1298C variant acts as a BC risk factor, particularly in a Western Asia population.

Association of Intake Folate and Related Gene Polymorphisms with Breast Cancer

Breast cancer is one of the most common malignancies in women worldwide and is associated with a variety of risk factors. Folate and vitamin B₁₂ are key elements of the one-carbon metabolism pathway where methylenetetrahydrofolate reductase (MTHFR) plays a significant role. Though many molecular and epidemiological studies have been performed to explore the relationship between intake folate, vitamin B₁₂, MTHFR gene polymorphism and breast cancer risk, there is no consensus to date. By reviewing the relevant literatures and summarizing the potential effect of dietary folate intake on MTHFR genes polymorphism and breast cancer risk, we conclude that MTHFR C677T gene polymorphism is associated with breast cancer risk among Asian, but not Caucasians, and the MTHFR A1298C gene polymorphism is not a susceptibility factor of breast cancers. Concomitant low activity of MTHFR enzyme resulted from C677T gene polymorphism and low dietary folate intake is associated with increased breast cancer risk.

Vitamin D receptor (VDR) gene FokI, BsmI, ApaI, and TaqI polymorphisms and osteoporosis risk: a meta-analysis

Background

Osteoporosis is a disease of the bones in which the density of the bones decreases. The prevalence of this disease greatly varies in different populations of the world. Numerous studies have been investigated VDR gene polymorphisms as osteoporosis risk in different ethnic groups. In present meta-analysis, the aim is to find out the role of VDR gene polymorphisms (FokI, BsmI, ApaI, and TaqI) in osteoporosis risk.

Methods

Suitable case-control studies for present meta-analysis were retrieved from four electronic databases. Open Meta-Analyst program was used for statistical analyses.

Results

Studies investigated BsmI (65 studies; 6880 cases/8049 controls), ApaI (31 studies; 3763 cases/3934 controls), FokI (18 studies; 1895 cases/1722 controls), and TaqI (26 studies; 2458 cases/2895 controls) polymorphisms that were included in the present meta-analysis. A significant association was found between the dominant model of FokI (ORff + Ffvs.FF = 1.19, 95% CI = 1.04–1.36, p = 0.01, I2 = 39.36%) in the overall analysis and recessive model of the Caucasian population of TaqI polymorphism (ORTT + Ttvs.tt = 1.35, 95% CI = 1.11–1.63, p = 0.002, I2 = 50.07%) with osteoporosis. On the other hand, no such effect is found in any other genetic models and in any other gene polymorphisms of the overall analyses or sub-group analyses.

Conclusion

In conclusion, the authors found that the dominant model of FokI in the overall analysis and recessive model of TaqI in the Caucasian population are significantly associated with the development of osteoporosis.

Evaluation of COMT Gene rs4680 Polymorphism as a Risk Factor for Endometrial Cancer

Catechol-O-methyletransferase (COMT) enzyme is involved in the inactivation of catecholamine and catechol estrogens. Catechol estrogens have carcinogenic potential and DNA damaging ability. Several studies investigated COMT Val158Met polymorphism as risk factor for endometrial cancer but the results were inconclusive. Hence the objective of present study was to find out exact association between COMT gene Val158Met polymorphism and endometrial cancer by a meta-analysis. Pubmed, Google Scholar, Springer Link and Science Direct databases were searched for case-control articles which investigated COMT Val158Met polymorphism in endometrial cancer cases. All statistical analysis was performed using MetaAnalyst and Mix programs. The results of meta-analysis suggested that there were no association between COMT Val158Met polymorphism and endometrial cancer risk (allele contrast model-OR_{A vs. G} = 0.97, 95% CI = 0.86-1.10, p = 0.67; co-dominant model-OR_{AG vs. GG} = 0.91, 95% CI = 0.77-1.06, p = 0.23; homozygote model-OR_{AA vs. GG} = 1.01, 95% CI = 0.84-1.19, p = 0.29; dominant model-OR_{AA+AG vs. GG} = 0.93, 95% CI = 0.77-1.11, p = 0.43; recessive model-OR_{AA vs. AG+GG} = 1.02, 95% CI = 0.89-1.20, p = 0.62). Publication bias was absent. Subgroup analysis based on source of controls was also performed. In conclusion, results of present meta-analysis showed no association between COMT Val158Met polymorphism and susceptibility to endometrial cancer.

Catechol-O-methyltransferase gene Val158Met polymorphism and obsessive compulsive disorder susceptibility: a meta-analysis

Obsessive-compulsive disorder (OCD) is a common psychiatric disorder that affects approximately 1-3% of the general population. It is characterized by disabling obsessions (intrusive unwanted thoughts) and/or compulsions (ritualized repetitive behaviors). Catechol-O-methyltransferase (COMT) enzyme has an important role in inactivation of dopamine and higher dopamine levels may be implicated in OCD, hence COMT gene is a suitable candidate for OCD. Several case-control studies have evaluated the role of COMT Val 158Met (rs4680;472G- > A) polymorphism as a risk factor for OCD but the results remained inconclusive, hence present meta-analysis was designed to find out correct assessment. All studies that investigated the association of COMT gene Val158Met polymorphism with OCD risk, were considered in the present meta-analysis. Statistical analysis was performed with the software program MetaAnalyst. In the current meta-analysis, 14 case-control studies with 1435 OCD cases and 2753 healthy controls were included. The results indicated significant association between COMT Val158Met polymorphism and OCD risk using allele contrast, homozygote and dominant models (OR_{A vs G} = 1.14; 95% CI = 1.02-1.27; p = 0.01; OR_AAvs.GG = 1.33; 95% CI = 1.09-1.62, p = 0.004; OR_{AA + AGvs.GG} = 1.14; 95% CI = 1.0-1.32; p = 0.04). In subgroup analysis based on case gender, meta-analysis of male cases showed significant association using all five genetic models (OR_AAvsGG = 1.99; 95%CI = 1.42-2.59; p = <0.001; OR_{AA + AGvs.GG} = 1.59; 95% CI = 1.20-2.10; p = 0.001), but did not show any association between COMT Val 158Met polymorphism and OCD risk in females. In conclusion, results of present meta-analysis supports that the COMT Val158Met polymorphism is a risk factor for OCD especially for males.

MTHFR gene polymorphisms in hypothyroidism and hyperthyroidism among Jordanian females

OBJECTIVE

Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA methylation that is associated with autoimmune pathology. We investigated the association between MTHFR genetic polymorphisms at g.677C>T and g.1298A>C and their haplotypes, and the risk of thyroid dysfunction among Jordanian females.

SUBJECTS AND METHODS

A case-control study involving 98 hypothyroidism cases, 66 hyperthyroidism cases and 100 controls was conducted. Polymerase chain reaction/restriction fragment length polymorphism technique was performed to determine genotypes. Statistical analysis using SPSS software was performed.

RESULTS

Genetic analysis showed a significant difference in genotype frequency of g.1298A>C between cases, and controls [hypothyroidism: AA (45.9%), AC (37.8%), CC (16.3%); hyperthyroidism: AA (9.1%), AC (69.7%), CC (21.2%); controls: AA (37.8%), AC (29.6%), CC (32.7%); CChypo vs. AAhypo: 2.55, 95% CI: (1.18-5.52); OR at least on Chypo: 1.79, 95% CI: (1.07-2.99)]; CChyper vs. AAhyper: 4.01, 95% CI: (1.79-9.01); OR at least on Chyper: 0.18, 95% CI: (0.07-0.48)]. There was no significant difference in genotype frequency of g.677C>T between cases and controls [hypothyroidism: CC (50.0%), CT (32.7%), TT (17.3%); hyperthyroidism: CC (77.3%), CT (15.2%), TT (7.6%); controls: CC (55.6%), CT (32.3%), TT (12.1%)]. There was a significant difference of MTHFR haplotypes among hypothyroidism cases and controls. TA and CC had a lower hypothyroidism risk whereas; TC showed a higher risk.

CONCLUSIONS

g.1298A>C genetic polymorphism of MTHFR may modulate the risk of thyroid disease. CC, TA, and TC haplotypes affect the risk of hypothyroidism. Larger samples should be included in the future to verify the role of MTHFR polymorphisms in thyroid diseases.

Strong Association of C677T Polymorphism of Methylenetetrahydrofolate Reductase Gene With Nosyndromic Cleft Lip/Palate (nsCL/P)

Methylenetetrahydrofolate reductase (MTHFR) is essential for DNA biosynthesis and the epigentic process of DNA methylation. It has been reported that abnormal DNA methylation contributes to the pathogenesis of congenital anomalies. There were many published case control studies assessing the associations of MTHFR C677T polymorphism with risks of nosyndromic cleft lip with and without palate (nsCL/P), but with inconsistent results. To derive a more precise estimation of the relationship, a meta-analysis was performed. Eligible articles were identified by search of databases including PubMed, Science Direct, Google Scholar and Springer Link up to December, 2015. Finally, a total of 22 studies with 3724 nsCL/P cases and 5275 controls were included in the present meta-analysis. Odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) were pooled to assess the association. Subgroup analysis based on ethnicity was also performed. All statistical analyses were done by MIX program. Meta-analysis results suggested that MTHFR C677T polymorphism contributed to the increased nsCL/P risk in overall population using four genetic models except homozygote model (for T vs. C: OR = 1.24, 95% CI = 1.1-1.4; for TT + CT vs. CC: OR = 1.29, 95% CI = 1.04-1.59; for CT vs. CC: OR = 1.26, 95% CI = 0.98-1.63; for TT vs. CC: OR = 1.02, 95% CI = 0.74-1.4; for TT vs. CT + CC: OR = 1.36, 95% CI = 1.05-1.74). In conclusion, results of present meta-analysis suggested that MTHFR C677T polymorphism is significantly associated with nonsyndromic orofacial cleft.

Methylenetetrahydrofolate reductase A1298C genetic variant& risk of schizophrenia: A meta-analysis

BACKGROUND & OBJECTIVES

Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme of folate metabolism, whose role in schizophrenia is debatable. Numerous case-control studies have investigated the association of MTHFR A1298C polymorphism with schizophrenia, but results are controversial. The aim of the present study was to find the association between MTHFR A1298C gene polymorphism and schizophrenia.

METHODS

PubMed, Google Scholar, Science Direct and Springer link databases were searched for case-control association studies in which MTHFR A1298C polymorphism was investigated as a risk factor for schizophrenia. In all, 19 studies with 4049 cases and 5488 controls were included in this meta-analysis. Odds ratios (ORs) with 95 per cent confidence intervals (CIs) were used as an association measure.

RESULTS

The results of meta-analysis reported a significant association between A1298C polymorphism and schizophrenia risk in overall comparisons in all genetic models (C vs. A: OR=1.13, 95% CI=1.01-1.27, P=0.02; CC vs. AA: OR=1.20, 95% CI=1.03-1.39, P=0.02; AC vs. AA: OR=1.13, 95% CI=1.03-1.23, P=0.009; AC+CC vs. AA: OR=1.14, 95% CI=1.02-1.24, P=0.002; CC vs. AA+AC: OR=1.17, 95% CI=1.01-1.35, P=0.04).

INTERPRETATION & CONCLUSIONS

MTHFR A1298C polymorphism was found to be a risk factor for schizophrenia and might have played a significant role in the pathogenesis of schizophrenia.

Methylenetetrahydrofolate Reductase C677T Polymorphism and Risk for Male Infertility in Asian Population

Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme of folate pathway and required for DNA synthesis and methylation. MTHFE C677T polymorphisms is reported as risk factors for various diseases and disorders like birth defects, metabolic, neurological, psychiatric disorders, and cancers. Several studies have investigated association between the MTHFR C677T polymorphism and male infertility. To assess the risk associated with MTHFR C677T polymorphism in Asian population, a meta-analysis was performed. Included articles were collected from the following electronic databases: PubMed, Google Scholar, and Science direct up to March 2015. Risk was estimated as pooled odds ratios (ORs) with confidence intervals (CIs) for assessment. Seventeen case-control studies involving 4392 breast infertile males and 3667 fertile males were found suitable for the inclusion in the present meta-analysis. Results showed that the C677T polymorphism was significantly associated with male infertility in Asian population using all the five genetic models (OR_{T vs. C} (allele contrast model) = 1.86, 95% CI 1.7-2.0; OR_{TT vs. CC} (homozygote model) = 1.96, 95% CI 1.67-2.30; OR_{CT vs. CC} (co-dominant model) = 1.40, 95% CI 1.18-1.62; OR_{TT+CT vs. CC} (dominant model) = 1.53, 95% CI 1.30-1.77; OR_{TT vs. CT+CC} (recessive model) = 1.67, 95% CI 1.44-1.92). In conclusion, results of present meta-analysis strongly supported an association between C677T polymorphism and male infertility in Asians.

Polymorphisms in the MTHFR gene are associated with recurrence risk in lymph node-positive breast cancer patients

Purpose

The aim of this study is to clarify the relationship between recurrence risk of breast cancer and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms.

Patients and methods

Breast cancer patients who had undergone surgery in Gaziantep University Oncology Hospital between June 2005 and June 2012 were followed-up and retrospectively enrolled in this study. Blood samples were collected from all patients to assess MTHFR C677T polymorphisms. Stage according to tumor–node–metastasis system, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 status, grade of disease, menopausal status, and administered chemotherapy or hormonal therapy were recorded. Effects of these parameters on recurrence risk were evaluated using univariate analysis and multivariate binary logistic regression model.

Results

Association of MTHFR C677T polymorphisms with recurrence risk was evaluated in 298 patients whose median age was 47 years (range: 21–79 years). In all patients, age (odds ratio [OR] =0.953, P=0.005) and N3 lymph node status (OR =6.293, P=0.001) were found to affect the recurrence risk. While MTHFR homozygote genotype did not have an effect on recurrence risk in all patients, increased risk was observed in lymph node-positive subgroup (OR =4.271; 95% CI 1.515–12.023; P=0.006). Adjusting for age, tumor size (T), and node status (N), MTHFR homozygote genotype had more statistically significant risk for recurrence (OR =3.255; 95% CI 1.047–10.125; P=0.041).

Conclusion

MTHFR TT genotype was found to be associated with increased recurrence risk in patients with lymph node-positive breast cancer.

Association between MTHFR gene 1298A>C polymorphism and breast cancer susceptibility: a meta-analysis based on 38 case-control studies with 40,985 subjects

Background

Studies investigating the association between the methylenetetrahydrofolate reductase (MTHFR) gene 1298A>C polymorphism and the risk of breast cancer have reported inconsistent results. So, we performed this updated meta-analysis and tried to give a more precise estimation of association between MTHFR gene 1298A>C polymorphism and breast cancer susceptibility.

Methods

Relevant studies published before 1 January 2016 were identified by searching PubMed and EMBASE. The strength of relationship between the MTHFR gene 1298A>C polymorphism and breast cancer susceptibility was assessed using odds ratio (OR) and corresponding 95 % confidence interval (95 % CI). The meta-analysis was performed using Stata 11.0 software.

Results

A total number of 38 case-control studies including 18,686 cases and 22,299 controls were identified. No association was found in five genetic models (dominant model: OR = 0.99, 95 % CI 0.99–1.00, P = 0.218; recessive model: OR = 1.00, 95 % CI 0.97–1.02, P = 0.880; homozygote genetic model: OR = 0.99, 95 % CI 0.98–1.01, P = 0.390; heterozygote genetic model: OR = 0.99, 95 % CI 0.97–1.00, P = 0.138; and allele contrast genetic model: OR = 0.99, 95 % CI 0.98–1.01) for MTHFR gene 1298 A>C polymorphism and breast cancer susceptibility. In the subgroup analysis stratified by source of control, decreased risk of breast cancer was found in studies with hospital-based controls in dominant model (OR = 0.98, 95 % CI 0.96–1.00, P = 0.037).

Conclusions

Our meta-analysis suggested that there is no significant association between MTHFR gene 1298A>C polymorphism and breast cancer susceptibility for overall population.

Associations between genetic variation in one-carbon metabolism and LINE-1 DNA methylation in histologically normal breast tissues

Genome-wide DNA hypomethylation is an early event in the carcinogenic process. Percent methylation of long interspersed nucleotide element-1 (LINE-1) is a biomarker of genome-wide methylation and is a potential biomarker for breast cancer. Understanding factors associated with percent LINE-1 DNA methylation in histologically normal tissues could provide insight into early stages of carcinogenesis. In a cross-sectional study of 121 healthy women with no prior history of cancer who underwent reduction mammoplasty, we examined associations between plasma and breast folate, genetic variation in one-carbon metabolism, and percent LINE-1 methylation using multivariable regression models (adjusting for race, oral contraceptive use, and alcohol use). Results are expressed as the ratio of LINE-1 methylation relative to that of the referent group, with the corresponding 95% confidence intervals (CI). We found no significant associations between plasma or breast folate and percent LINE-1 methylation. Variation in MTHFR, MTR, and MTRR were significantly associated with percent LINE-1 methylation. Variant allele carriers of MTHFR A1289C had 4% lower LINE-1 methylation (Ratio 0.96, 95% CI 0.93-0.98), while variant allele carriers of MTR A2756G (Ratio 1.03, 95% CI 1.01-1.06) and MTRR A66G (Ratio 1.03, 95% CI 1.01-1.06) had 3% higher LINE-1 methylation, compared to those carrying the more common genotypes of these SNPs. DNA methylation of LINE-1 elements in histologically normal breast tissues is influenced by polymorphisms in genes in the one-carbon metabolism pathway. Future studies are needed to investigate the sociodemographic, environmental and additional genetic determinants of DNA methylation in breast tissues and the impact on breast cancer susceptibility.

Relationship between Genetic Polymorphisms in MTHFR (C677T, A1298C and their Haplotypes) and the Incidence Of Breast Cancer among Jordanian Females--Case-Control Study

BACKGROUND

Breast cancer is a major cause of morbidity and mortality in Jordan and worldwide. Abnormality of DNA methylation is a possible mechanism for the development of cancer. Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA methylation. Our aim was to study the association between genetic polymorphisms of MTHFR at two sites (C677T and A1298C) and their haplotypes and the risk of breast cancer among Jordanian females.

MATERIALS AND METHODS

A case-control study involving 150 breast cancer cases and 150 controls was conducted. Controls were age-matched to cases. Polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) technique and sequencing were conducted to determine the genotypes.

RESULTS

There was a significant difference in genotype frequency of C677T in the 41-60 year age category [cases: CC (37.4%), CT (49.5%) and TT (13.2%); controls: CC (56.3%), CT (35.6%) and TT (8%), p=0.04; ORTT vs. CC: 2.5, 95% CI: (0.9-6.9); ORat least on T: 2.1, 95%CI: (1.2-3.9)]. There was no significant difference in genotype frequency of A1298C between cases and controls [cases: AA (46.6%), AC (41.8%) and CC (11.6%); controls: AA (43%), AC (47.4%) and CC (9.6%); p=0.6]. There was a significant difference of MTHFR genetic polymorphism haplotypes among breast cancer cases and controls [cases/control: CA: 38.3/45.4%; CC: 28.9/25.2%; TA: 29.2/21; TC: 3.6/8.3; p value=0.01; ORTA vs. CA=1.6; 95% CI (1.1-2.5); p=0.02].

CONCLUSIONS

Genetic polymorphism of MTHFR C677T may modulate the risk of breast cancer especially in the 41-60 year age group. Additionally, TA haplotype amends the risk of breast cancer. Future studies with a larger sample size are needed to validate the role of MTHFR genetic polymorphisms in breast cancer.