• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4559-4565
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• 2013

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in DNA synthesis and repair. We here aimed to investigate two common polymorphisms, C677T and A1298C, with genotype and haplotype frequencies in colorectal cancer (CRC) cases among Jordanian. Materials and Methods: 131 CRC cases were studied for MTHFR C677T and A1298C polymorphisms, compared to 117 controls taken from the general population, employing the PCR-RFLP technique. Results: We found the frequency of the three different genotypes of MTHFR C677T among Jordanians to be CC: 61.7%, CT: 35.2%, and TT 3.1% among CRC cases and 50.9%, 38.8% and 10.3% among controls. Carriers of the TT genotype were less likely to have CRC (OR=0.25; 95%CI: 0.076-0.811; p=0.021) as compared to those with the CC genotype. Genotype analysis of MTHFR A12987C revealed AA: 38.9%, AC: 45%, and CC 16% among CRC cases and 37.4%, 50.4% and 12.2% among controls. There was no significant association between genetic polymorphism at this site and CRC. Haplotype analysis of MTHFR polymorphism at the two loci showed differential distribution of the TA haplotype (677T-1298A) between cases and controls. The TA haplotype was associated with a decreased risk for colorectal cancer (OR=0.6; 95% CI: 0.4-0.9, p=0.03). Conclusions: The genetic polymorphism of MTHFR at 677 and the TA haplotype may modulate the risk for CRC development among the Jordanian population. Our findings may reflect an importance of genes involved in folate metabolism in cancer risk.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.3
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• pp.152-158
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• 2017

Objective: To identify the associations between polymorphisms of the 3'-untranslated region (UTR) of methylenetetrahydrofolate reductase (MTHFR) gene, which codes for an important regulatory enzyme primarily involved in folate metabolism, and idiopathic recurrent pregnancy loss (RPL) in Korean women. Methods: The study population comprised 369 RPL patients and 228 controls. MTHFR 2572C > A, 4869C > G, 5488C > T, and 6685T > C 3'-UTR polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis or by TaqMan allelic discrimination assays. Natural killer cell proportions were determined by flow cytometry. Results: The MTHFR 2572-5488-6685 (A-C-T) haplotype had an adjusted odds ratio of 0.420 (95% confidence interval, 0.178-0.994; p= 0.048) for RPL. Analysis of variance revealed that MTHFR 4869C > G was associated with altered $CD56^+$ natural killer cell percentages (CC, $17.91%{\pm}8.04%$; CG, $12.67%{\pm}4.64%$; p= 0.024) and folate levels (CC, $12.01{\pm}7.18mg/mL$; CG, $22.15{\pm}26.25mg/mL$; p= 0.006). Conclusion: Variants in the 3'-UTR of MTHFR are potential biomarkers for RPL. However, these results should be validated in additional studies of ethnically diverse groups of patients.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2491-2494
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• 2012

The current study was performed to assess any association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and risk of lung cancer in Henan province. This case-control study involved94 patients with newly histological confirmed lung cancer and 78 healthy controls. Genotyping was achieved with peripheral blood lymphocytes DNA and association of the polymorphism with risk of lung cancer was estimated by unconditional logistic regression analysis. The frequencies of the MTHFR 667TT genotype were 37.2% in cases compared with 23.1% in controls (${\chi}^2$ = 4.008, P = 0.045). Individuals with the 667CC/CT genotype displayed a significantly reduced risk of lung cancer compared with those with the TT genotypes [adjusted odds ratio (OR), 0.506; 95% confidence interval (95% CI), 0.258 - 0.991]. The C667T polymorphism might have a significant effect on the occurrence of lung cancer in Henan province.

• Korean Journal of Biological Psychiatry
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• v.12 no.2
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• pp.114-122
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• 2005

Objectives:Recently in schizophrenia high incidence of MTHFR(methylenetetrahydrofolate reductase), which is a main relating enzyme that reduce homocysteine level, genetic variations were reported. So we examined serum homocysteine level and MTHFR gene polymorphism in Korean schizophrenics. Method:We compared serum homocysteine level and MTHFR polymorphism between 235 schizophrenics (100male, 135female) and 235 normal controls(100male, 135female). C677T and A1298C polymorphism of MTHFR gene were analyzed. Results:1) C677T genetic mutation(CT and TT) were more frequent in schizophrenia group than normal control group(p<0.01). But the difference of A1298C mutation frequency was not found between two groups. 2) In schizophrenia patients, TT genotype of C677T mutation showed significantly higher homocysteine level (29.99uM/L) than other group(CT:13.34uM/L, CC:9.34uM/L p<0.01). 3) MTHFR 677 TT homogeneous mutation genotype showed two times more risk(odds ratio=2.15) than 677CC normal genotype in schizophrenia. Conclusion:Some schizophrenia patients with high homocysteine serum level may have C677T TT genotype. In that case, folate ingestion could be a good management for clinical improvement.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8093-8100
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• 2016

Background: Genetic and environmental factors play important roles in pathogenesis of digestive tract cancers like those in the esophagus, stomach and colorectum. Folate deficiency and methylenetetrahydrofolate reductase (MTHFR) as an important enzyme of folate and methionine metabolism are considered crucial for DNA synthesis and methylation. MTHFR variants may cause genomic hypomethylation, which may lead to the development of cancer, and MTHFR gene polymorphisms (especially C677T and A1298C) are known to influence predispositions for cancer development. Several case control association studies of MTHFR C677T polymorphisms and colorectal cancer (CRC) have been reported in different populations with contrasting results, possibly reflecting inadequate statistical power. Aim: The present meta-analysis was conducted to investigate the association between the C677T polymorphism and the risk of colorectal cancer. Materials and Methods: A literature search of the PubMed, Google Scholar, Springer link and Elsevier databases was carried out for potential relevant articles. Pooled odds ratio (OR) with corresponding 95 % confidence interval (95 % CI) was calculated to assess the association of MTHFR C677T with the susceptibility to CRC. Cochran's Q statistic and the inconsistency index (I2) were used to check study heterogeneity. Egger's test and funnel plots were applied to assess publication bias. All statistical analyses were conducted by with MetaAnalyst and MIX version 1.7. Results: Thirty four case-control studies involving a total of 9,143 cases and 11,357 controls were retrieved according to the inclusion criteria. Overall, no significant association was found between the MTHFR C677T polymorphism and colorectal cancer in Asian populations (for T vs. C: OR=1.03; 95% CI= 0.92-1.5; p= 0.64; for TT vs CC: OR=0.88; 95%CI= 0.74-1.04; p= 0.04; for CT vs. CC: OR = 1.02; 95%CI= 0.93-1.12; p=0.59; for TT+ CT vs. CC: OR=1.07; 95%CI= 0.94-1.22; p=0.87). Conclusions: Evidence from the current meta-analysis indicated that the C677T polymorphism is not associated with CRC risk in Asian populations. Further investigations are needed to offer better insight into any role of this polymorphism in colorectal carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3937-3942
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• 2012

Background: Many studies have investigated possible association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and ovarian cancer risk, but the impact is still unclear owing to the obvious inconsistencies. This study was performed to quantify the strength of the association with a metaanalysis. Methods: We searched the PubMed, Embase, and CNKI databases for studies relating the association between MTHFR C677T polymorphism and ovarian cancer risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Results: Finally, eight studies with a total of 3,379 ovarian cancer cases and 4,078 controls were included into this meta-analysis. Overall the showed that MTHFR C677T polymorphism was not associated with ovarian cancer risk under all genetic models ($OR_{T\;versus\;C}$ = 1.03, 95%CI 0.90-1.18; $OR_{TT\;versus\;CC}$ = 1.08, 95%CI 0.79-1.47; $OR_{TT\;versus\;TC+CC}$ = 1.05, 95%CI 0.80-1.37; $OR_{TT+TC\;versus\;CC}$ = 1.05, 95%CI 0.86-1.21). Meta-analyses of studies with confirmation of HWE also showed no significant association. Subgroup analyses by ethnicity showed there was no significant association in the Caucasians but MTHFR C677T polymorphic variant T contributed to increased risk of ovarian cancer in East Asians. No evidence of publication bias was observed. Conclusion: Meta-analyses of available data show that MTHFR C677T polymorphism is not associated with ovarian cancer risk in Caucasians, but the MTHFR polymorphic variant T may contribute to increased risk in East Asians.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4627-4630
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• 2012

Purpose: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with pancreatic cancer, but the published studies have yielded inconsistent results. This study assessed the relationship between MTHFR gene polymorphisms and the risk for pancreatic cancer using a meta-analysis approach. Methods:A search of Google scholar, PubMed, Cochrane Library and CNKI databases before April 2012 was performed, and then associations of the MTHFR polymorphisms with pancreatic cancer risk were summarized. The association was assessed by odds ratios (ORs) with 95% confidence intervals (CIs). Publication bias was also calculated. Results: Four relative studies on MTHFR gene polymorphisms (C667T and A1298C) were included in this meta-analysis. Overall, C667T (TT vs. CC:OR=1.61,95%CI=0.78-3.34; TT vs. CT: OR=1.41,95%CI=0.88-2.25; Dominant model:OR=0.68,95%CI=0.40-1.17; Recessive model: OR=0.82,95%CI=0.52-1.30) and A1298C (CC vs. AA:OR=1.01,95%CI=0.47-2.17; CC vs. AC: OR=0.99,95%CI=0.46-2.14; Dominant model:OR=1.01, 95%CI=0.47-2.20; Recessive model: OR=1.01,95%CI=0.80-1.26) did not increase pancreatic cancer risk. Conclusions: This meta-analysis indicated that MTHFR polymorphisms (C667T and A1298C) are not associated with pancreatic cancer risk.

• Journal of Nutrition and Health
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• v.39 no.3
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• pp.264-273
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• 2006

Elevated maternal plasma homocysteine concentrations have been associated with adverse pregnancy outcomes. Serum homocysteine levels may be affected by the MTHFR genotypes and the nutritional status of B vitamins including vitamin $B_2,\;B_6$, folate and vitamin $B_{12}$. We investigated whether postnatal growth measurements were influenced by maternal MTHFR genotypes and their mid-pregnancy serum vitamin B and homocysteine levels. In 130 pregnant women of 24-28 wks of gestation, the MTHFR genotypes, serum B vitamins and homocysteine concentrations were analyzed. Physical growth status was assessed in their offsprings by measuring height, weight, and head and chest circumferences from birth up to 24 months. Serum homocysteine levels were higher in the subjects with T/T genotype than those with the C/T or C/C. Heights and head and chest circumferences of offsprings from the T/T mothers were significantly lower than those from the C/C or C/T mothers only when the serum homocysteine levels were above the median. The mean height of offsprings from the T/T mothers was significantly lower than those from the C/C and C/T mothers. The mean weight and head circumferences of offsprings born from the mothers whose mid-term pregnancy PLP levels were in the lowest quartile was significantly lower than those from mothers in the highest quartile. Heights and head circumferences of offsprings from the T/T mothers were significantly lower than those from the C/C or C/T mothers only when the serum FAD levels were in the lowest quartile. These results suggest that postnatal growth up to 24 months may be influenced by the maternal C677T MTHFR genotypes, and mid-pregnancy serum homocysteine and vitamin B status.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1203-1208
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• 2012

Background: Previous studies concerning the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and colorectal cancer risk in Asian populations generated conflicting results. A meta-analysis was therefore performed to allow a more reliable estimate of any link. Methods: Relevant studies concerning the association between the MTHFR C677T polymorphism and risk of colorectal cancer were included into this meta-analysis. The quality of the studies was assessed according to a predefined scale. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined for this gene-disease association using fixed or random effect models according to the heterogeneity between included studies. Results: Finally, 21 studies with a total of 6692 cases and 8266 controls were included. Meta-analyses showed that there was an obvious association of the MTHFR 677T allele with decreased risk of colorectal cancer (OR = 0.91, 95%CI=0.85-0.98, P=0.011). Subgroup analyses by country further identified this association, with dietary folate as the main source of heterogeneity. Conclusion: The MTHFR 677T allele is associated with a lower risk of colorectal cancer in Asian populations, and there is effect modification by population plasma folate.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3943-3947
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• 2012

Objective: Findings for associations between the methylenetetrahydrofolate reductase (MTHFR) A1298C gene polymorphism and head and neck cancer risk have been conflicting. We therefore performed a meta-analysis to derive a more precise relationship. Methods: Ten published case-control studies were collected and odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between MTHFR A1298C polymorphism and head and neck cancer risk. Sensitivity analysis and publication bias assessment also were performed to guarantee the statistical power. Results: Overall, no significant association between MTHFR A1298C polymorphism and head and neck cancer risk was found in this meta-analysis (C vs. A: OR=1.04, 95%CI=0.87-1.25, P=0.668, Pheterogeneity<0.001; CC vs. AA: OR=1.07, 95%CI=0.70-1.65, P=0.748, $P_{heterogeneity}<0.001$; AC vs. AA: OR=1.06, 95%CI=0.88-1.27, P=0.565, $P_{heterogeneity}<0.001$; CC+AC vs. AA: OR=1.06, 95%CI=0.86-1.30, P=0.571, $P_{heterogeneity}<0.001$; CC vs. AA+AC: OR=1.02, 95%CI=0.69-1.52, P=0.910, $P_{heterogeneity}<0.001$). Similar results were also been found in succeeding analysis of HWE and stratified analysis of ethnicity. Conclusion: In conclusion, our meta-analysis demonstrates that MTHFR A1298C polymorphism may not be a risk factor for developing head and neck cancer.