ABSTRACT. Methylenetetrahydrofolate reductase (MTHFR) plays an important role in folate metabolism and is involved in DNA synthesis, DNA repair and DNA methylation. The two common functional polymorphisms of MTHFR, C677T and A1298C have been associated with several diseases, including cancer. We made a case-control study to analyze a possible association of MTHFR gene polymorphisms C677T and A1298C with risk for colorectal cancer in an eastern Chinese Han population of 137 patients with a confirmed histopathological diagnosis of CRC and 145 age-and gender-matched controls with no history of cancer. DNA was isolated from peripheral blood samples and the genotypes were determined by PCR-RFLP. The concentrations of folate in plasma were measured by chemiluminescence immunoassay. The MTHFR 677TT genotype had a protective effect against colorectal cancer, with an odds ratio (OR) = 0.467 (95% confidence interval ( for individuals who carried both MTHFR 677CC and 1298CC genotypes, the OR of colorectal cancer was 0.103 (95%CI = 0.012-0.900); among individuals who carried both MTHFR 677TT and 1298AC genotypes, the OR for risk of colorectal cancer was 0.169 (95%CI = 0.044-0.654). MTHFR 677TT+CT genotypes had a significantly lower plasma folate concentration than those with the MTHFR 677CC genotype. MTHFR 1298AC+CC genotypes had a lower plasma folate concentration than those with the MTHFR 1298AA genotype (P < 0.05). In conclusion, subjects with the MTHFR 677TT and MTHFR 1298CC genotypes appeared to have a significantly lower risk for colorectal cancer. MTHFR haplotypes 677CC/1298CC and 677TT/1298AC were less common in cases than in controls. These haplotypes, when compared to the most common haplotype 677CC/1298AA, were associated with a decreased risk for colorectal cancer. We conclude that plasma folate level is influenced by MTHFR genotypes.

Previous studies investigating the association between 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and colon cancer risk have generated conflicting results. The aim of our meta-analysis was to clarify the precise association. A systematic literature search was conducted to identify all relevant studies. Pooled odds ratio (ORs) with 95% confidence interval (CI) were used to estimate the strength of the association. In this meta-analysis, a total of 13 articles, involving 5,386 cases and 8,017 controls met the inclusion criteria. Overall, a significant association was found between colon cancer risk and the MTHFR C667 polymorphism

Background: Hyperuricemia (HUA) is caused by genetic and dietary factors. However, little is known about the ways in which diet and gene interactions influence HUA or the role of dietary patterns in HUA. Objectives: We aimed to explore the association between dietary patterns and HUA as well as dietary patterns and gene interactions in HUA among the Yi ethnic group of China. Methods: Food consumption information was collected using a semi-quantitative food frequency questionnaire. Vein blood samples were collected after overnight fasting from all participants and DNA was extracted from peripheral blood leukocytes. Dietary patterns were derived using factor analysis.Results: The study included 2646 participants aged 18–88 years with a HUA prevalence of 26.8%. Three major dietary patterns were identified and shown to be associated with HUA prevalence, with meat-based diets having a higher association with HUA than plant-based or regionally specific diets. The frequency of the T allele at ABCG2 rs2231142 and SLC2A9 rs11722228 loci was higher in HUA than in non-HUA populations. An additive interaction between a meat-based diet and the rs2231142 locus was associated with the risk of HUA. The relative excess risks of interaction (RERI), attributable proportion of interaction (AP), and synergy index (S) were 0.482 (95% CI 29 = 0.012,0.976),0.203 (95% CI = 0.033,0.374), 1.544 (95% CI = 1.012,2.355), respectively. Conclusions: The meat-based dietary pattern was associated with an increased risk of HUA. There was an additive interaction between a meat-based dietary pattern and the ABCG2 rs2231142 locus in study participants. Individuals with the rs2231142 T allele had a higher frequency of HUA than those with the rs2231142 GG allele. Individuals with the rs2231142 T allele but a healthy dietary pattern could have a reduced HUA risk.