• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5853-5860
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• 2014

Background: Methylenetetrahydrofolate (MTHFR) is the key enzyme of the folate metabolic pathway and several studies have pointed to association between the MTHFR C677T polymorphism and breast cancer risk. Although significant association was observed in some studies, in others no clear link could be established. Objective: A meta-analysis of published Asian case control studies was therefor carried out to shed further light on any C677T breast cancer association. Materials and Methods: PubMed, Springer Link, Google Scholar and Elsevier databases were searched for case control studies of associations between MTHFR C677T polymorphism and breast cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A total of 36 studies including 8,040 cases and 10,008 controls were included in the present meta-analysis. Results: Overall, a significantly elevated breast cancer risk was associated with the T allele and TT genotype in homozygote comparison and dominant genetic models when all studies were pooled into the meta-analysis (T vs C (allele contrast model): OR=1,23, 95%CI=1.13-1.37, p=0.000 ; TT vs CC(homozygote model): OR=1.38, 95%CI=1.16-1.63, p=0.0003; TT+CT vs CC (dominant model): OR=1.12, 95%CI=1.01-1.23, p=0.02). Conclusions: The present meta-analysis strongly suggested a significant association between the MTHFR C677T polymorphism and risk of breast cancer in Asian populations.

• Proceedings of the Korean Nutrition Society Conference
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• 2002.05a
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• pp.142-142
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• 2002

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3763-3766
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• 2012

Background: Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate, and the role of the MTHFR C677T polymorphism in pancreatic carcinogenesis is still controversial. Methods: A literature search was performed using Pubmed and CNKI databases for published studies through May 2012. We performed a meta-analysis of all relevant case-control studies that examined the association between MTHFR C677T polymorphism and pancreatic cancer risk. Results: Finally, 9 individual case-control studies with a total of 1,299 pancreatic cancer cases and 2,473 controls were included into this meta-analysis. Results: This metaanalysis showed there was an obvious association between MTHFR C677T polymorphism and pancreatic cancer risk in East Asians (for allele model, OR = 1.67, 95%CI 1.11-2.51; For homozygote model, OR = 2.77, 95%CI 1.40-5.48; for recessive model, OR = 1.96, 95%CI 1.54-2.50; for dominant model, OR = 2.11, 95%CI 1.01-4.41). However, no significant association was found in Caucasians. Conclusions: The MTHFR C677T polymorphism is associated with pancreatic cancer risk, and a race-specific effect may exist in this association. More studies with a larger sample size are needed to further clarify this association.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.569-573
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• 2012

Early diagnosis and better prognosis of ovarian cancer is still a challenge. Besides environmental risk factors, genetic factors have established a role in pathogenesis of ovarian cancer. Methods: A case-control and a prospective study design conducted in 224 ovarian cancer patients and 432 controls in Chinese population. MTHFR C677T genotyping was done by PCR-RFLP. Results: Patients with ovarian cancer is associated with a higher less number of delivery and less frequent oral contraceptive use. When potential confounding factors adjusted logistic regression analysis between cases and controls were performed, significant association was obtained for 677T/T genotype and ovarian cancer (OR=3.13, 95% CI=1.59-5.72). Cox regression survival analysis showed individuals carrying T/T genotype had significantly increased HR for death in ovarian cancer patients (HR=2.86, 95% CI=1.27-7.93). In conclusion, we observed that the MTHFR C677T polymorphism is associated with the susceptibility and survival of ovarian cancer in Chinese population.

• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1045-1052
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• 2002

Hyperhomocysteinemia, resulted from an interaction between the mutation of MTHFR gene and B vitamin deficiency, is suggested as a possible cause for complications and adverse outcomes of pregnancy. The purpose of the present study was to investigate the relationship between the intakes of B vitamins and serum homocysteine concentrations with the C677T mutation in the MTHFR genotypes in 135 normal pregnant women of 24-28 weeks of gestation. Dietary intake of B vitamins did not differ among the three genotypes, but the negative correlation between dietary folate intake and the serum homocysteine level was the strongest in the T/T type (r ＝ -0.249) than in other genotypes (C/T: r＝ -0.040, C/C:r＝ 0.126, p＜0.05). Among the subject with the T/T type, the pregnant women who consumed folate less than 50% of the RDA had higher serum homocysteine levels than those who consumed folate greater than 125% of the RDA (10.4$\pm$5.9 vs 7.0$\pm$1.5 $\mu$mol/L, p＜0.05). Serum homocysteine levels were higher in the women with micronutrient supplements than those with no supplements in the T/T type, but such relation was not present in the C/C or the C/T type. In conclusion, serum homocysteine concentrations were influenced by the interrelationship between the MTHFR polymorphisms and dietary folate intake or micronutrient supplementation.

• Korean Journal of Clinical Oncology
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• v.9 no.2
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• pp.80-86
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• 2013

Purpose: Hypermethylation of human mut L homologue 1 (hMLH1) promoter region is known to cause sporadic microsatellite instability (MSI) colorectal cancers. 5,10-methylenetetrahydrofolate reductase (MTHFR) is the key enzyme in folate metabolism, acting as a methyl donor for DNA methylation. In this study, we investigate whether the polymorphism of MTHFR 677C>T plays a role in the alteration of the promoter-specific hypermethylation, predisposing to MSI colorectal cancers. Methods: Total of 487 sporadic colorectal cancer patients in CHA Bundang Medical Center were collected. MSI was identified when two or more are positive among five microsatellite markers (BAT25, BAT26, D17S250, D5S346, D2S123). The others were classified as microsatellite stable (MSS). Polymorphism of MTHFR 677C>T was genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: MSI was observed in 65 of 487 patients (12.73%). MSI colorectal cancers showed similar clinicopathological features with previously reported; younger age onset, right-sided preponderance, mucinous and poorly differentiated histology, lower stage, fewer lymph node metastases than MSS tumors (each P<0.05). The frequency of MTHFR 677TT genotype was 17.7% in the MSI group higher than 14.6% in the MSS group (P=0.17). Although not statistically significant, compared to the MTHFR 677CC referent, MTHFR 677 CT+TT genotype was more likely to have MSI than MSS (odds ratio, 1.81; 95% confidence interval, 0.94 to 3.68; P=0.06). Conclusion: This study demonstrated higher frequency of MTHFR 677TT genotype in MSI colorectal cancers. Furthermore, individuals with MTHFR 677CT+TT variant type might potentially develop MSI rather than MSS colorectal cancers.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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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.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.3
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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.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.3
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• pp.168-173
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• 2011

Objective: To examine the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and hyperhomocysteinemia in women with unexplained recurrent miscarriages (RM) and to investigate the association between MTHFR genotype variants and alloimmune activation, proportion of peripheral blood natural killer (pbNK) cells. Methods: A total of 39 patients with a history of two or more unexplained miscarriages were recruited to this study. The controls were women who had a live birth without a history of RM (n=50). The proportion of pbNK cells was measured by flow cytometry. Plasma homocysteine levels and the incidence of the MTHFR variant of the RM and control groups were compared. The proportion of pbNK cells was compared to the MTHFR variants in the RM group. Results: No differences were found between the two groups' mean plasma homocysteine levels ($7.6{\pm}1.5{\mu}mol$/L vs. $7.1{\pm}2.1{\mu}mol$/L) or incidence of the MTHFR genotype variant (CC, 35% vs. 33%; CT, 40% vs. 53%; and TT, 25% vs. 14%). In the RM group, individuals with the TT variant ($7.7{\pm}1.1{\mu}mol$/L) had higher homocysteine levels than those with the CC and CT variants ($7.4{\pm}1.9{\mu}mol$/L and $7.4{\pm}1.2{\mu}mol$/L) and those with the CT variant ($19.2{\pm}8.1%$) had a higher proportion of CD3-/CD56+ pbNK cells than those with the CC and TT variants ($17.7{\pm}6.6%$ and $17.9{\pm}7.0%$), but the results of both comparisons were statistically insignificant. Conclusion: These preliminary results show no difference in plasma homocysteine levels between the RM and control groups or among MTHFR genotype variants in the RM group, which may suggest that the plasma homocysteine level is difficult to use as a predictive marker of RM in the Korean population. A study of a larger number of patients is needed.

• 대한예방의학회:학술대회논문집
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• 2002.10a
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• pp.362-363
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• 2002