The polymorphism of methylenetetrahydrofolate reductase C677T but not A1298C contributes to gastric cancer

Associations between methylenetetrahydrofolate reductase polymorphisms and hepatocellular carcinoma risk: An update meta-analysis and trial sequential analysis

AIM

To evaluate the associations between the methylenetetrahydrofolate reductase (MTHFR) single-nucleotide polymorphisms (SNPs) and hepatocellular carcinoma (HCC) with meta-analysis and trial sequential analysis.

METHODS

PubMed, Embase, the Google Scholar, Wan fang database, VIP database, and China National Knowledge Infrastructure were extensively searched before April 2021. Odds ratios (ORs) and 95% confidence interval (95% CI) were calculated. Review Manager Version 5.3, STATA version 12.0 and TSA 0.9.5.10 Beta software were used.

RESULTS

Nineteen studies with 6941 HCC patients and 9436 controls were finally included. The MTHFR rs1801133 (C677T) SNP was associated with increased HCC risk under heterozygote genetic model (OR = 1.10, 95% CI = [1.01, 1.20]). For Subgroup analysis, increased risks of HCC were detected in Mongoloid, Chinese. For MTHFR rs1801131 (A1298C) SNP, increased risk of HCC was only observed in Caucasians (allelic: OR = 1.86, 95% CI = [1.49, 2.31]; homozygote: OR = 3.39, 95% CI = [2.18, 5.27]), interesting decreased risk was detected in Mongoloid (recessive: OR = 0.30, 95% CI = [0.15, 0.58]; homozygote: OR = 0.41, 95% CI = [0.24, 0.72]). Sensitivity analysis indicated stability in our results. Publication bias was not detected based on Begg test and Egger test. Trial sequential analysis indicated further studies to confirm the associations in MTHFR C677T polymorphism.

CONCLUSION

The MTHFR rs1801133 SNP was associated with an increased risk of HCC in Mongoloid population especially in Chinese. Increased HCC risk is also observed in Caucasian population for the MTHFR rs1801131 SNP, and decreased risk of HCC is remarkably discovered in Mongoloid and Chinese subgroups, which need further validation.

MTHFR C677T and A1298C Polymorphisms in Breast Cancer, Gliomas and Gastric Cancer: A Review

Folate (vitamin B9) is found in some water-soluble foods or as a synthetic form of folic acid and is involved in many essential biochemical processes. Dietary folate is converted into tetrahydrofolate, a vital methyl donor for most methylation reactions, including DNA methylation. 5,10-methylene tetrahydrofolate reductase (MTHFR) is a critical enzyme in the folate metabolism pathway that converts 5,10-methylenetetrahydrofolate into 5-methyltetrahydrofolate, which produces a methyl donor for the remethylation of homocysteine to methionine. MTHFR polymorphisms result in reduced enzyme activity and altered levels of DNA methylation and synthesis. MTHFR polymorphisms have been linked to increased risks of several pathologies, including cancer. Breast cancer, gliomas and gastric cancer are highly heterogeneous and aggressive diseases associated with high mortality rates. The impact of MTHFR polymorphisms on these tumors remains controversial in the literature. This review discusses the relationship between the MTHFR C677T and A1298C polymorphisms and the increased risk of breast cancer, gliomas, and gastric cancer. Additionally, we highlight the relevance of ethnic and dietary aspects of population-based studies and histological stratification of highly heterogeneous tumors. Finally, this review discusses these aspects as potential factors responsible for the controversial literature concerning MTHFR polymorphisms.

MTHFR C677T and A1298C polymorphisms and lung cancer risk in a female Chinese population

Objective

To examine the relationship between polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene and susceptibility to lung cancer in a female Chinese population.

Method

A hospital-based case-control study of 388 cases and 388 controls was conducted. Two polymorphisms in MTHFR were detected using TaqMan methods.

Results

The MTHFR C677T polymorphism was associated with the risk of lung cancer and lung adenocarcinoma. Carriers with the TT genotype of C677T were observed to have an increased risk of lung cancer and lung adenocarcinoma (the ORs were 1.550 and 1.588, respectively). By contrast, the A1298C polymorphism had a negative relationship with the risk of lung cancer and lung adenocarcinoma; compared with the AA genotype carriers, the CC genotype carriers had a lower risk of lung cancer and adenocarcinoma in the female Chinese population (ORs were 0.302 and 0.215, respectively). In the stratified analyses, we observed only the A1298C polymorphism in the CC genotype carriers with a statistically significant reduction in the risk of non-small-cell lung cancer, compared to the AA genotype carriers. No significant statistical association was found between the MTHFR gene polymorphisms and risk of the residual subtype of lung cancer.

Conclusion

This study provides evidence that the MTHFR C677T polymorphism may contribute to the development of lung cancer and lung adenocarcinoma in a female Chinese population. However, the MTHFR A1298C polymorphism may be associated with the decreasing risk of lung cancer.

5,10-Methylenetetrahydrofolate reductase polymorphisms and colon cancer risk: a meta-analysis

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 (TT vs CC+CT: OR=0.79; 95%CI=0.65-0.96; p=0.017). Stratification by ethnicity revealed that MTHFRC667 was associated with colon cancer risk in the non-Asian group (TT vs CC+CT:OR=0.77, 95%CI=0.68-0.89, p=0.000; TT vs CC: OR=0.84, 95%CI=0.73-0.97, p=0.016). Stratification by source of control indicated that MTHFR C667 also correlated with colon cancer risk in the population-based subgroup (TT vs CC: OR=0.85, 95%CI=0.74-0.97, p=0.017; TT vs CC+CT: OR=0.78, 95%CI=0.68-0.89, p=0.000) and hospital-based subgroup (TT vs CC+CT: OR=0.65, 95%CI=0.49-0.86, p=0.003). However, risk was significantly increased for MTHFR A1298C polymorphisms and colon cancer risk in hospital-based studies (C vs A: OR=1.52, 95%CI=1.26-1.83, p=0.000; CC+AC vs AA: OR=1.93, 95%CI=1.47-2.49, p=0.000) but reduced in population-based studies (CC vs AA: OR=0.83, 95%CI=0.70-0.99, p=0.042). In conclusion, the results of our meta-analysis suggest that the MTHFR C667 polymorphism is associated with reduced colon cancer risk, especially for non-Asian populations.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and gastric cancer susceptibility

AIM: To identify the association between methylenetetrahydrofolate reductase (MTHFR) polymorphisms and gastric cancer (GC) susceptibility.

METHODS: Systematic searches were performed on the electronic databases PubMed, ISI, Web of knowledge, CNKI and Wanfang, as well as manual searching of the references of the identified articles. A total of 26 papers were included in this meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95%CI were used to evaluate the associations between MTHFR polymorphisms and GC risk. The I² statistics were used to evaluate between-study heterogeneity. Sensitivity analysis was also performed.

RESULTS: Increased risk was found for the MTHFR C677T polymorphism under four genetic models (TT + CT vs CC: OR = 1.23, P = 0.002; T vs C: OR = 1.15, P = 0.001; TT vs CC: OR = 1.37, P = 0.0005; TT vs CT + CC: OR = 1.17, P = 0.0008). Subgroup analysis by ethnicity suggested that C677T polymorphism conferred a risk of GC in eastern but not in western populations. Stratification by tumor site showed an association between the C677T polymorphism and gastric cardia cancer and non-cardia GC in the worldwide population and in eastern populations. Regardless of comparisons with controls or diffuse-type GC, a positive association was found for the C677T polymorphism and an increased risk of intestinal-type GC in the whole population and in western populations. With regard to the A1298C polymorphism, we found that genotype CC was significantly decreased and conferred protection against GC in eastern populations (CC vs AA: OR = 0.44, P = 0.03; CC vs AC + AA: OR = 0.46, P = 0.04).

CONCLUSION: MTHFR C677T polymorphism is a risk factor for GC, and the A1298C polymorphism may be a protective factor against GC in eastern populations.

Quantitative assessment of the associations between DNA repair gene XRCC3 Thr241Met polymorphism and gastric cancer

Gastric cancer is one of the most prevalent types of cancer in the world today. Recently, there is a large sample volume of published case-control studies on XRCC3 Thr241Met polymorphism with gastric cancer. This will have an important impact on published article by meta-analysis regarding XRCC3 Thr241Met polymorphism with gastric cancer. Therefore, it is necessary to update by meta-analysis to comprehensively investigate the relationship between DNA repair gene XRCC3 Thr241Met polymorphism and gastric cancer. To preciously examine the association between the XRCC3 Thr241Met polymorphism and gastric cancer, we undertook a meta-analysis of 12 case-control studies. The association between the XRCC3 Thr241Met polymorphism and gastric cancer risk was assessed by odds ratios together with their 95 % confidence intervals using a fixed-effects model or random-effects model. We found that the XRCC3 Thr241Met polymorphism was not associated with an increased gastric cancer risk. However, the XRCC3 Thr241Met polymorphism was associated with decreased gastric cancer risk in Asians. In addition, there is no evidence of association on XRCC3 Thr241Met polymorphism with response to chemotherapy and prognosis in gastric cancer. The XRCC3 Thr241Met polymorphism might influence gastric cancer risk in Asians.