Association between the MTHFR C677T polymorphism and gastric cancer susceptibility: A meta-analysis of 5,757 cases and 8,501 controls

Association of Dietary Antioxidant Vitamin Intake and Gastric Cancer Risk According to Smoking Status and Histological Subtypes of Gastric Cancer: A Case-Control Study in Korea

Smoking is a risk factor for gastric cancer (GC) and causes oxidative stress. Antioxidant vitamins may protect against oxidative stress. This study aimed to determine the association between dietary antioxidant vitamin intake and GC risk according to smoking status and the histological subtype. This case-control study included 286 pairs of patients with GC and controls aged 20-79 years enrolled at two hospitals from 2002 to 2006, matched by age (± 2 years), sex, hospital, and participation period (± 1 years). Dietary information was collected using a quantitative food frequency questionnaire (FFQ). When stratified by smoking status, increased intake of vitamin C (OR = 0.38; 95% CI = 0.17-0.84 for highest vs. lowest; P for trend = 0.033) and folate (OR = 0.28; 95% CI = 0.12-0.64 for highest vs. lowest; P for trend = 0.003) decreased GC risk in nonsmokers. Vitamin C (P for interaction = 0.043) and folate (P for interaction =0.015) levels were significantly associated with smoking status. Similar results were observed in nonsmokers with diffuse and mixed types of GC, but not in those with intestinal type of GC. Therefore, we found an inverse association between higher intake of dietary vitamin C and folate with the risk of GC among nonsmokers. These protective associations were strong in nonsmokers with diffuse and mixed types of GC.

The combination of methylenehydrofolate reductase C677T polymorphism screening and gastrointestinal tumor markers detection may be an early screening method for gastrointestinal cancer related to helicobacter pylori infection

Methyltetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism, and its single nucleotide polymorphism (SNP) site C677T may be associated with gastrointestinal cancer. However, the relationship between MTHFR C677T polymorphism and gastrointestinal tumor markers carcinoma embryonic antigen (CEA), carbohydrate antigen 199 (CA199) and carbohydrate antigen 724 (CA724) in Helicobacter pylori (H. pylori) infection is not specified. This study aims to identify the association between MTHFR C677T polymorphism and gastrointestinal tumor markers (CEA, CA199 and CA724) in H. pylori infection. The relationship between MTHFR C677T polymorphism and gastrointestinal tumor markers in 58 patients with H. pylori infection and 94 non-infected patients was studied. We found that TT genotype was a susceptibility factor of H. pylori infection, which was also associated with increased CEA and CA724 levels. Moreover, there was a negative additive interaction between MTHFR gene C677T polymorphism and CEA levels in H.pylori infection. Meanwhile, there were significant differences in CEA levels between MTHFR C677T polymorphism and H.pylori infection. The presence of T allele led to a decrease in CEA levels when ¹³C urea breath test (¹³C-UBT) was positive, while the presence of T allele led to an increase in CEA levels when ¹³C-UBT was negative. Therefore, we suggest that healthy people should take MTHFR C677T polymorphism screening, combined with ¹³C-UBT and gastrointestinal tumor markers detection, which can screen out the susceptible population of H. pylori, and help to detect gastrointestinal cancer in the early stage.

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.

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.

Associations of the MTHFR rs1801133 polymorphism with gastric cancer risk in the Chinese Han population

In recent years, increasing evidence has implicated the importance of mutations in the MTHFR gene in the risk of gastric cancer risk. A single nucleotide polymorphism (SNP) in the MTHFR gene (rs1801133) may serve a critical role in gastric cancer. A hospital-based case-controlled study was performed to assess the risk of the rs1801133 polymorphism on gastric cancer. A total of 307 patients with gastric cancer and 560 patients in the control group were recruited. Genomic DNA was extracted from peripheral blood and genotyped for rs1801133 using the ligase detection reaction. The relationship between rs1801133 and gastric cancer risk was evaluated by unconditional logistical regression analysis. The rs1801133-TT genotype was associated with a borderline significantly decreased risk of gastric cancer [(TT vs. CC, adjusted odds ratio (OR)=0.54, 95% confidence intervals (CI)=0.35-0.83; P=0.006; CT vs. CC, adjusted OR=0.59, 95% CI=0.44-0.79, P<0.001; and TT/CT vs. CC, adjusted OR=0.61, 95% CI=0.44-0.83, P=0.001), and further analysis showed the relationship was evident amongst older patients and patients who never drank alcohol. The C>T mutation at rs1801133 of the MTHFR gene was associated with a decreased risk of gastric cancer in older individuals and those who never drink.

Association of MTHFR C677T polymorphism with severity and localization of chronic atrophic gastritis patients without Helicobacter pylori infection: a case control study

Background

Previous reports indicate that the methylenetetrahydrofolate reductase (MTHFR) 677C > T polymorphism plays a role in gastric cancer. However, whether it influences the development and progression of atrophic gastritis remains ambiguous. We aimed to determine the possible relationship between MTHFR C677T polymorphism and the severity of atrophic gastritis.

Methods

A total of 128 patients without Helicobacter pylori infection were included in the study. The severity of gastric atrophy was assessed by pathological diagnosis using OLGA and OLGIM Gastritis Staging System. MTHFR 677C > T genotyping was performed by digital fluorescence molecular hybridization. Categorical variables were analyzed by percentages using the χ² test.

Results

In this study, the TT genotype was significantly more frequent among Helicobacter pylori-negative patients aged ≤44 years (age ≤ 44 years vs. > 44 years, P = 0.039). Patients with TT genotype showed a higher ratio of incisura with atrophy or intestinal metaplasia (TT vs. CC + CT, P = 0.02). Furthermore, TT genotype was associated with more severe lesions compared with the CC + CT genotypes (TT vs. CC + CT for atrophy: P = 0.07; for intestinal metaplasia: P = 0.01; for moderate-to-severe lesions: P = 0.01). OLGA and OLGIM stages III-IV were observed more frequently in patients with TT genotype compared with CC + CT genotypes (for OLGA: P = 0.003; for OLGIM: P = 0.036).

Conclusions

The MTHFR 677C > T TT genotype showed an increased risk of moderate-to-severe lesions by OLGA and OLGIM stages, and these results indicate that MTHFR C677T polymorphism may act as a predictive marker for precancerous gastric lesions, especially in Helicobacter pylori-negative patients aged ≤44 years.

State of Art of Cancer Pharmacogenomics in Latin American Populations

Over the past decades, several studies have shown that tumor-related somatic and germline alterations predicts tumor prognosis, drug response and toxicity. Latin American populations present a vast geno-phenotypic diversity due to the great interethnic and interracial mixing. This genetic flow leads to the appearance of complex characteristics that allow individuals to adapt to endemic environments, such as high altitude or extreme tropical weather. These genetic changes, most of them subtle and unexplored, could establish a mutational profile to develop new pharmacogenomic therapies specific for Latin American populations. In this review, we present the current status of research on somatic and germline alterations in Latin America compared to those found in Caucasian and Asian populations.