Can MTHFR C677T and A1298C Polymorphisms Alter the Risk and Severity of Sporadic Breast Cancer in Brazilian Women?

Lack of Association of C677T Methylenetetrahydrofolate Reductase Polymorphism with Breast Cancer Risk in Mali

Methylenetetrahydrofolate reductase (MTHFR) plays a major role in the metabolism of folates and homocysteine, which in turn can affect gene expression and ultimately promote the development of breast cancer. Thus, mutations in the MTHFR gene could influence homocysteine, methionine, and S-adenosylmethionine levels and, indirectly, nucleotide levels. Imbalance in methionine and S-adenosylmethionine synthesis affects protein synthesis and methylation. These changes, which affect gene expression, may ultimately promote the development of breast cancer. We therefore hypothesized that such mutations could also play an important role in the occurrence and pathogenesis of breast cancer in a Malian population. In this study, we used the PCR-RFLP technique to identify the different genotypic profiles of the C677T MTHFR polymorphism in 127 breast cancer women and 160 healthy controls. The genotypic distribution of the C677T polymorphism in breast cancer cases was 88.2% for CC, 11.0% for CT, and 0.8% for TT. Healthy controls showed a similar distribution with 90.6% for CC, 8.8% for CT, and 0.6% for TT. We found no statistical association between the C677T polymorphism and breast cancer risk for the codominant models CT and TT (p > 0.05). The same trend was observed when the analysis was extended to other genetic models, including dominant (p = 0.50), recessive (p = 0.87), and additive (p = 0.50) models. The C677T polymorphism of MTHFR gene did not influence the risk of breast cancer in the Malian samples.

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.

Strong Correlation of MTHFR Gene Polymorphisms with Breast Cancer and its Prognostic Clinical Factors among Egyptian Females

Introduction:

Globally, Breast cancer (BC) is considered the second most common type of cancer and the principal cause of death among affected women. Aim: In this study, we targeted to demonstrate the association of MTHFR single gene polymorphisms (SNPs) with the susceptibility of breast cancer, in addition to its correlation with the clinical patient features.

Patients and Methods:

This work was conducted on 100 Egyptian females with breast cancer and 60 healthy matched controls. Clinical examinations and pathological investigations were recorded. Genotyping of MTHFR polymorphisms C677T (rs1801133) and A1298C (rs1801131) by using Restriction Fragment length Polymorphisms (RFLP) and Sequencing assays were performed. Univariate, Multivariate and Haplotype analysis for the allelic frequencies and the association with clinicopathological features of BC were assessed.

Results:

The present data showed a strong significant association between the CT and TT of MTHFR (C677T), and AC and CC of (A1289C) with the susceptibility of BC showing highly statistical P- value (0.001). It was also demonstrated that the most frequent haplotype of the two loci of MTHFR (rs1801133-rs1801131) was TC. The latter was strongly associated with the aggressive clinical features of each of tumor size, advanced stage, involvement of cancer in lymph nodes, overexpression of HER2neu and dual negativity of both ER and PR hormones.

Conclusions:

SNPs within the MTHFR gene (C677T) and (A1289C) have strong correlation with BC among Egyptian females; These SNPs should be considered as important prognostic markers for identifying the individuals at high risk of developing BC and its progression.

Relationship between MTHFR Gene Polymorphisms and Gastrointestinal Tumors Development: Perspective from Eastern Part of Turkey

BACKGROUND

Gastric and esophageal cancers are 2 of the most prevalent cancer types worldwide. Polymorphisms in the genes that code the methylenetetrahydrofolate reductase (MTHFR) enzyme increase the formation of both cancer types. In this study, it was aimed to research the relationship between the existence of MTHFR C677T and A1298C polymorphisms in patients with gastric and esophageal cancer and the lifespans of patients.

METHODS AND MATERIALS

This prospective study was performed at Van Yuzuncu Yil University. Included in the study were 30 patients with esophageal tumors, 70 patients with gastric tumors, and 61 healthy volunteers. From each of the patients, 5 mL of blood was drawn. DNA was isolated via kits with spin-column technology.

RESULTS

It was concluded that the risk of developing gastric cancer was 4.13 times higher in individuals who had the AC genotype of the A1298C polymorphism when compared to those who had the AA genotype, while the risk was 2.91 times higher in individuals who had the CC genotype when compared to those who had the AA genotype (P = 0.001, P = 0.027). Carriers of the AC genotype of the A1298C polymorphism had 2.89 times higher risk of developing esophageal cancer when compared to those who had the AA genotype (P = 0.033). It was determined that individuals who had the 1298 CC genotype were not at higher risk of developing esophageal cancer when compared to those with the AA genotype (P = 0.863). It was concluded that individuals who had the TT genotype of the C677T polymorphism were not at higher risk of developing gastric and esophageal cancers when compared to those who had the 677CC genotype (P > 0.05). There was no difference in terms of the life spans of the patients with regards to the genotypes (P > 0.05).

CONCLUSION

The results showed that the A1298C polymorphism on the MTHFR gene can be a risk factor for gastric and esophageal cancer in eastern Turkey. These polymorphisms may have no effect on the life spans of the patients.

Methylenetetrahydrofolate Reductase (MTHFR) Gene rs1801133 C>T Polymorphisms and Lung Cancer Susceptibility: An Updated Meta-analysis

Objective: The aim of this study was to investigate the methylenetetrahydrofolate reductase (MTHFR) gene rs1801133 C>T polymorphisms and lung cancer susceptibility by pooling openly published data.

Methods: Electronic databases of Medline, Web of Science, Embase, Google scholar, CBM and CNKI were systematic searched to find the relevant studies related to MTHFR gene rs1801133 C>T polymorphisms and lung cancer susceptibility. The odds of TT, CT and CC alleles in lung cancer patients compared with healthy controls was pooled by the effect size of odds ratio (OR) and corresponding 95% confidence interval (95%CI) under random or fixed effect model. Publication bias was analyzed by Begg’s funnel plot and Egger’s line regression test.

Results: Overall, twenty-one studies relevant to MTHFR gene rs1801133 C>T polymorphisms and lung cancer susceptibility were included. The pooled data showed subject with T allele had significant increased risk of developing lung cancer in dominant (OR=1.14, 95%CI: 1.01-1.28, p<0.05), recessive (OR=1.26, 95%CI:1.08-1.48, p<0.01) and homologous (OR=1.36, 95%CI:1.12-1.65, p<0.01) genetic model. Begg’s funnel plot and Egger’s line regression test showed significant publication bias in all genetic models.

Conclusion: Based on present data, subjects with TT or CT alleles may have increased susceptibility to lung cancer. However, due to significant publication bias, the conclusion should be drawn with caution and should be proved by further well-designed case-control or cohort studies relevant to MTHFR gene rs1801133 C>T polymorphisms and lung cancer risk.

C677T and A1298C methylenetetrahydrofolate reductase polymorphisms and breast cancer susceptibility among Latinos: a meta-analysis

BACKGROUND

Previous meta-analyses have shown an ethnic dependency of the C677T and the A1298C methylenetetrahydrofolate reductase (MTHFR) polymorphisms, with no focus on the Latino population. For Latinos, many studies have examined these polymorphisms and breast cancer susceptibility, yielding no concise result. Therefore, we undertook this meta-analysis to determine the effect these polymorphisms have on breast cancer risk for Latinos.

METHODS

PubMed, EBSCO, LILACS, Scopus, and Latin American-specific databases were searched for studies exploring the association between the MTHFR polymorphisms and breast cancer susceptibility in Latinos until January 2019. Genotype distributions were extracted and, depending on the level heterogeneity determined by the ψ²-based Q test and the I² test, fixed-effects or random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) for the heterozygous, homozygous, dominant, recessive, and allelic genetic models. No publication bias was detected by the Begg-Mazumdar's test and Egger's test.

RESULTS

Of the 280 retrieved publications, 9 studies were included: 9 for the C677T polymorphism and 5 for the A1298C polymorphism. For the C677T polymorphism, there was an elevated risk for the homozygous (OR 1.42, 95% CI 1.05-1.92), the dominant (OR 1.16, 95% CI 1.02-1.31), the recessive (OR 1.33, 95% CI 1.01-1.75), and the allelic model (OR 1.17, 95% CI 1.03-1.33, p < 0.01). No association between the A1298C polymorphism and the risk to develop breast cancer was determined.

CONCLUSION

The results indicated that, for Latinos, the C677T polymorphism is associated with a significant risk for developing breast cancer, whereas the A1289C polymorphism does not.

The association between MTHFR polymorphism and cervical cancer

Cervical cancer is an extremely prevalent disease worldwide. The purpose of this study was to illustrate the relationship between methylenetetrahydrofolate reductase (MTHFR) polymorphisms or methionine synthase reductase (MTRR) polymorphisms and cervical cancer. There were 372 women who performed genetic and folic acid assessments. For the MTHFR C677T, there was no significant difference in the distribution of C allele and T allele in the three groups. However, the mutant C allele of MTHFR A1298C was significantly higher in the cancer group than in the normal group. Similarly, the mutant G allele of MTRR A66G was also higher than the normal group. The serum folic acid levels were gradually decreased with the development of cervical lesions. Serum folate levels in 4–9 ng/ml and ≤4 ng/ml were both significantly associated with cervical cancer risk. However, the MTHFR C677T polymorphism was not associated with the risk of cervical cancer or CIN. In contrast, the MTHFR A1298C polymorphism could increase the risk of both cervical cancer and CIN. In addition, the MTRR A66G polymorphism was only associated with the risk of cervical cancer but not CIN.