• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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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.

• Clinical and Experimental Reproductive Medicine
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• 제29권3호
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• pp.215-222
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• 2002

Objective : Previous studies have suggested that hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR C677T) mutations are associated with increased risk of recurrent spontaneous abortion (RSA). Recently, a second site polymorphism in MTHFR, 1298A-->C, which changes a glutamic acid into an alanine residue, was shown to be associated with a decreased enzyme activity. We tested whether the variant alleles of MTHFR C677T and A1298C are risk factor (biomarker) for RSA. Materials and Methods: We analyzed DNA from a case-control study in the Korean DNA was extracted from blood samples of 118 patients with RSA and 123 healthy fertile patients as the controls. MTHFR variant alleles were determined by a PCR-restriction fragment length polymorphism assay. Results: We found no evidence for an association between 677TT genotype and risk of RSA (OR=1.95, 95% CI=$0.84{\sim}4.50$, p=0.12). However, the MTHFR 1298AC (OR=0.36, 95% CI=$0.20{\sim}0.63$, p=0.0004) and 1298AC+CC (OR=0.35, 95% CI=$0.20{\sim}0.61$, p=0.0002) genotypes were lower among 118 RSA cases compared with 123 controls, conferring a 2.8-fold decrease in risk of RSA, respectively. Moreover, the combined genotypes of MTHFR 677CC/1298AC (OR=0.30, 95% CI=$0.10{\sim}0.88$, p=0.029) and 677CT/1298AC (OR=0.77, 95% CI=$0.60{\sim}0.99$, p=0.043) also showed significantly lower risk than those with MTHFR 677CC/1298AA type. Conclusion: MTHFR 1298AC, MTHFR 677CC/1298AC and 677CT/1298AC genotypes may represent genetic markers for the protection of RSA at least in Korean women.

• Asian Pacific Journal of Cancer Prevention
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• 제15권22호
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• pp.9707-9711
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• 2014

Background: Acute lymphoblastic leukemia (ALL) is a complex disease caused by interactions between hazardous exogenous or/and endogenous agents and many mild effect inherited susceptibility mutations. Some of them are known, but their functional roles still requireinvestigation. Age is a recognized risk factor; children with disease onset after the age of ten have worse prognosis, presumably also triggered by inherited factors. Materials and Methods: The MDR1 gene polymorphisms rs1045642, rs2032582 and MTHFR gene polymorphisms rs1801131 and rs1801133 were genotyped in 68 ALL patients in remission and 102 age and gender matched controls; parental DNA samples were also available for 42 probands. Results: No case control association was found between analyzed polymorphisms and a risk of childhood ALL development. Linkage disequilibrium was not observed in a family-based association study either. Only marginal association was observed between genetic marker rs2032582A and later disease onset (p=0.04). Conclusions: Our data suggest that late age of ALL onset could be triggered by mild effect common alleles.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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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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• 제13권5호
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• pp.2025-2029
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• 2012

Objective: Methylenetetrahydrofolate reductase (MTHFR) catalyzes the metabolism of folate and nucleotides needed for DNA synthesis and repair. Variations in MTHFR functions likely play roles in the etiology of lung cancer (LC). So far, several studies between MTHFR C677T polymorphism and LC provide controversial or inconclusive results. Methods: To better assess the purported relationship, we performed a meta-analysis of 14 publications. Eligible studies were identified by searching the Pubmed, Embase, Web of Science and Google Scholar databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Results: Overall, no significant association was detected between the MTHFR C677T polymorphism and LC risk, the same as in race subgroup. However, in the stratified analysis by histological type, significantly increased non-small-cell lung cancer (NSCLC) risk was indicated (T-allele vs. C-allele: OR = 1.11, 95%CI = 1.03-1.19; TT vs. CC: OR = 1.24, 95%CI = 1.09-1.41; TC vs. CC: OR = 1.11, 95%CI = 1.03-1.20 and TT+TC vs. CC: OR = 1.09, 95%CI = 1.03-1.15). At the same time, ever-smokers who carried T-allele (TT+TC) had a 10% decreased LC risk compared with CC genotype carriers. Conclusions: Our study provided evidence that the MTHFR 677T null genotype may increase NSCLC risk, however, it may protect ever-smokers against LC risk. Future studies with large sample sizes are warranted to further evaluate this association in more detail.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6333-6337
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• 2014

Background: In this case-control study, we aimed to investigate the relationship between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and lung cancer. Materials and Methods: Total 200 individuals including 100 patients with lung cancer and 100 controls were analyzed. Genotyping of MTHFR C677T was performed using PCR and RFLP methods. Results: The majority of the patients were men and 90% were smokers. We found that the risk ratio for development of LC was 13-times higher in smokers compared with non-smokers between patient and control groups in our study (OR:13.5, 95%CI:6.27-29.04, p:0.0001). Besides, the risk ratio for development of LC was nine times higher in individuals with cancer history in their family than those without cancer history (OR:9.65, 95%CI: 2.79-33.36; p:0.0001). When genotype distributions and allele frequencies were analyzed in the study groups, no significant difference was apparent (${\chi}^2$:0.53, p=0.76). In addition, no correlation between genotypes of MTHFRC677T polymorphism and histological type of LC was found (${\chi}^2$:0.99, p=0.60). Conclusions: These results suggest that there was no association between the MTHFR C677T polymorphism and lung cancer in the Turkish population.

• Clinical and Experimental Pediatrics
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• 제54권8호
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• pp.335-339
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• 2011

Purpose: Hyperhomocysteinemia is known as a risk factor for atherosclerosis. Preclinical arteriosclerosis is noted and premature atherosclerosis is known to be accelerated in Kawasaki disease (KD) patients. Genetic polymorphisms in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene result in elevated plasma homocysteine concentrations and are known to be associated with the development of coronary artery disease. Our hypothesis is that single nucleotide polymorphisms (SNPs) of the MTHFR gene are related to the development of KD and coronary artery lesions (CALs). Methods: For this study, we selected 3 candidate single nucleotide polymorphisms (SNPs) (rs2274976, rs1801131, and rs1801133) of MTHFR. These SNPs are located on chromosome 1p36.3. We included 101 KD patients and 306 healthy adults as controls in this study. CALs were seen in 38 patients. Genotypes of the selected SNPs were determined by direct sequencing and analyzed with SNPAlyze. Results: The genetic distribution and allelic frequency of the 3 MTHFR SNPs (rs2274976, rs1801131, and rs1801133) were not significantly different in patients with KD compared to the control group (P=0.71, 0.17, and 0.96, respectively). There was no difference in the genetic distribution of the MTHFR SNPs between the normal control group and the CAL group (P=0.43, 0.39, 0.52 respectively). Conclusion: The genetic distribution of the MTHFR SNPs (rs2274976, rs1801131, and rs1801133) was not different in the KD group compared to the control group. In addition, the genetic distribution of these SNPs was not different in the CAL group compared to the control group in the Korean population.

• Journal of Preventive Medicine and Public Health
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• 제38권4호
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• pp.437-442
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• 2005

Objectives : DNA methylation is one of the best characterized epigenetic mechanisms that play a regulatory role in genome programming and imprinting during embryogenesis. In this present study, we investigated the association between DNA methylation in the human placenta and the maternal folate and homocysteine concentrations on the Methylenetetrahydrofolatereductase (MTHFR) genetic polymorphism during pregnancy. Methods : We investigated 107 pregnant women who visited Ewha Woman's University Hospital for prenatal care during their $24{\sim}28$ weeks-period of gestation. During the second trimester, we measured the serum homocysteine and folate concentrations . The MTHFR 677 genetic polymorphism was determine by performing PCR-RFLP assay. The expression of DNA methylation in the human placentas was estimated by using immunohistochemistry method. Results : Serum folate was negatively correlated with the serum homocysteine concentration for all the MTHFR genotypes. We found positive correlation between the folate concentrations and the DNA methylation in the human placenta (p<0.05). An increasing concentration of homocysteine was associated with reduced DNA methylation in the human placenta. The coefficient value was -2.03 (-3.77, -0.29) on the regression model (p<0.05). Conclusion : These findings suggest that the maternal folate and homocysteine levels along with the MTHFR 677 genetic polymorphism during pregnancy affect the DNA methylation in the human placenta.

• Journal of Nutrition and Health
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• 제36권4호
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• pp.389-396
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• 2003

Maternal nutritional status has been shown to influence pregnancy outcomes. And the elevated maternal plasma homocysteine concentrations have been associated with adverse pregnancy outcomes. We investigated the effects of maternal serum levels of B vitamins and homocysteine, and the C677T MTHFR (5, 10-methylenetetrahydrofolate reductase) polymorphism on pregnancy outcomes. In 177 pregnant women of 24-28 wks of gestation, the MTHFR gene mutation, serum B vitamins and homocysteine concentrations were measured, and their pregnancy outcomes were investigated from medical records. The birth length, and 1- and 5-min Apgar scores of neonates in the T/T mothers were 45.4 $\pm$ 9.3 cm, 7.6 $\pm$ 3.2 and 8.5 $\pm$ 3.8, respectively, which were significantly lower than those in the C/T (48.6 $\pm$ 3.3 cm, 9.0 $\pm$ 0.2, 10.0 $\pm$ 0.2) or the C/C mothers (49.4 $\pm$ 1.9 cm, 9.0 $\pm$ 0.2, 10.0 $\pm$ 0.0). The birth weight, birth length and the gestational age of neonates at delivery from hyperhomocysteinemic mothers whose homocysteine levels higher than 15 $\mu$ mol were 2.5 $\pm$ 1.3 kg, 43.9 $\pm$ 9.0 cm, 35.4 $\pm$ 6.3 wk, respectively, which were significant lower than those from normohomocysteinemic mothers (3.1 $\pm$ 0.6 kg, 48.8 $\pm$ 3.6 cm, 38.5 $\pm$ 2.5 wk). The birth weight and birth length of neonates in mothers whose PLP levels were below the median were significantly lower than those from mothers with the PLP levels above the median. The 1- and 5-min Apgar scores of neonates were lower in mothers with the T/T MTHFR genotype than those with the C/T or C/C only when the serum PLP levels were below the median. The 1-, 5 min Apgar scores and birth length of neonates were lower in mothers with the T/T MTHFR genotype than those with the C/T or C/C only when the serum FMN levels were below the median. In conclusion, maternal B vitamin status, homocysteine and the C677T MTHFR genotype seem to have played an important role on pregnancy outcomes.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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• pp.3101-3109
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• 2015

Background: Methylenetetrahydrofolate reductase (MTHFR) is involved in amino acid synthesis and DNA function. Two common polymorphisms are reported, C677T and A1298C, that are implicated in a number of human diseases, including cancer. Objective: The association between MTHFR C677T and A1298C genotype and haplotype frequencies in risk for lung cancer (LC) was investigated in the Jordanian population. Materials and Methods: A total of 98 LC cases were studied for MTHFR C677T and A1298C polymorphisms, compared to 89 controls taken from the general population, employing the PCR-RFLP technique. Results: The frequency of the genotypes of MTHFR C677T among Jordanians was: CC, 59.6%, CT, 33%; and TT, 7.4% among LC cases and 49.4%, 40.2% and 10.3% among controls. No significant association was detected between genetic polymorphism at this site and LC. At MTHFR A12987C, the genotype distribution was AA, 29.5%; AC, 45.3%, and CC 25.3% among LC cases and 36.8%, 50.6% and 12.6% among controls. Carriers of the CC genotype were more likely to have LC (OR=2.5; 95%CI: 1.04-6; p=0.039) as compared to AA carriers. Smokers and males with the CC genotype were 9.9 and 6.7 times more likely to have LC, respectively ($OR_{smokers}=9.9$; 95%CI: 1.2-84.5, p=0.018; $OR_{men}=6.6$; 95%CI: 1.7-26.2, p=0.005). Haplotype analysis of MTHFR polymorphism at the two loci showed differential distribution of the CC haplotype (677C-1298C) between cases and controls. The CC haplotype was associated with an increased risk for lung cancer (OR=1.6; 95% CI: 1.03-2.4, p=0.037). Conclusions: The genetic polymorphism of MTHFR at 1298 and the CC haplotype (risk is apparently lower with the C allele at position 677) may modulate the risk for LC development among the Jordanian population. Risk associated with the 1298C allele is increased in smokers and in males. The results indicate that a critical gene involved in folate metabolism plays a modifying role in lung cancer risk, at least in the Jordanian population.