Introduction

Biomedical Reports

2049-9434 2049-9442

D.A. Spandidos

BR-0-0-01390

10.3892/br.2020.1390

Articles

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

Han

Zhiqiang

1 * Sheng

Huaming

2 3 * Gao

Qiuzhi

4 Fan

5 Xie

Xiang

1Department of Osteology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212000, P.R. China 2Department of Oncology, Jiangyin Hospital, Wuxi, Jiangsu 214400, P.R. China 3School of Medicine, Southeast University, Nanjing, Jiangsu 210000, P.R. China 4School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China 5Cancer Institute, Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu 212002, P.R. China 6School of International Relations & Public Affairs, Fudan University, Shanghai 200000, P.R. China

Correspondence to: Dr Zhiqiang Han, Department of Osteology, Affiliated Hospital of Jiangsu University, 438 Jiefang Road, Zhenjiang, Jiangsu 212000, P.R. China zjhzq0812@sina.com

^*Contributed equally

01 2021

17 11 2020

14 1

22 02 2020 23 10 2020

2020

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.

gastric cancer MTHFR rs1801133 polymorphism risk

Introduction

Gastric cancer is one of the most common types of cancer. Worldwide, gastric cancer has the fourth highest morbidity and the second highest mortality rate (1). However, the incidence and mortality of different types of gastric cancer vary; for example, there is a decrease in the incidence of non-cardia gastric cancer, concurrent with an increase in the morbidity and mortality rate of gastric cardia adenocarcinoma (2-5).

According to the statistics of Global Cancer in 2012, ~952,000 cases of stomach cancer were diagnosed, and there were >700,000 deaths, almost half of which came from China. Additionally, there were 405,000 new cases and 325,000 deaths in China (6). Developing countries have a higher proportion of gastric cancer cases, accounting for 70% of the worldwide total. Among these cases, East Asia accounts for ~50% of cases, and China is the worst affected, accounting for 45% of all gastric cancer-related deaths. Additionally, 42.6% of the incidence is attributed to China (7,8). Several studies have shown the importance of various environmental factors on the risk of gastric cancer (9). In addition to environmental factors, the risk of gastric cancer is also influenced by internal factors, for example, age, genetic factors, lifestyle and sex. In particular, genetic factors may impact gastric cancer.

5,10-methylene 4 hydrogen folate is a methylene 4 hydrogen folic acid reductase Methylenetetrahydrofolate reductase (MTHFR) catalyst, converts irreversibly into 5-methyl folate four hydrogen, which directs the distribution of folic acid derivatives to homocysteine remethylation and DNA methylation, or to biosynthesis of DNA and RNA, at a key metabolic branching point (10). Chromosome 1p36.3 contains 11 exons that encode MTHFR. More importantly, 5-MTHF is the only single carbon donor that produces homocysteine remethylation in the methionine cycle (11). The MTHFR gene contains >20 SNPs, some of which are non-synonymous and some of which are associated with cancer risk. In particular, genetic polymorphisms in the MTHFR gene are associated with colorectal cancer risk (12,13). A previous study found that rs4846048 increased the risk of colorectal cancer through its association with miR-522, and further regulated the survival and apoptosis of HeLa cells (14). Additionally, rs1801131 is associated with an increased risk of gastrointestinal toxicity (15), and the rs1801131-CC genotype is associated with sporadic breast cancer (16). The most frequently studied SNP is rs1801133, which is less common in gastric cancer; however, its role and prevalence in breast cancer and ovarian cancer have been studied (16-18).

It was found that rs1801133 was associated with the risk of colorectal cancer (19,20), ovarian cancer (17), gastric cancer (21) and liver cancer (22). To further verify whether rs1801133 is associated with the risk of gastric cancer, a case-controlled study was performed using individuals recruited from Zhenjiang (Jiangsu, China). The aim of the present study was to explore the relationship between rs1801133, environmental factors and the risk of gastric cancer.

Materials and methods <sec> <title>Ethics statement

The present hospital-based case-controlled study protocol was approved by the Ethics Committee for Human Subject study of Jiangsu University (Zhenjiang, China), and the study conformed to the guidelines of the Helsinki Declaration (23) on Ethical Behavior in Human Research.

Study population

All subjects in the present study, including the cases and controls, were of Chinese Han origin. A total of 307 patients with gastric cancer from the Affiliated People's Hospital of Jiangsu University and the Affiliated Hospital of Jiangsu University were collected between October 2014 and June 2016. Each patient was diagnosed with gastric cancer pathologically. The exclusion criteria were: Pre-existing cancer; the patient had undergone radiation or received chemotherapy; evidence of metastasis; or had an autoimmune disease. A total of 560 individuals with no cancer were recruited from the above two hospitals at the same time. Each of these individuals were interviewed to gather demographic data (such as age) and related risk factors (involving tobacco smoking and alcohol drinking). Participants who smoked at least 1 cigarette a day for 1 year were defined as ‘smokers’. Individuals who had more than 3 drinks a week for 6 months were considered ‘alcohol drinkers’. The median age was 63 years (age range, 40-90) in the case group and 62 years (age range, 40-88) in the control group. There were 223 males and 84 females amongst the case group, and 373 males and 187 females in the control group.

Genotyping

From each individual, 3-5 ml venous blood was collected. The sample was stored in a test tube lined with EDTA at 4˚C. Genomic DNA was extracted from whole blood samples using a commercially available DNA blood mini-kit (Qiagen, Inc.). Genotyping quality was determined using a procedure that included success rates of >95%, repeated genotyping, internal positive control samples, and Hardy-Weinberg Equilibrium (HWE) tests (24). The MTHFR tag SNP rs1801133 was assessed according to the HapMap Project and Haploview version 4.2 (ihg.gsf.de/cgi-bin/hw/hwa1.pl). The ligase detection reaction method was used to genotype rs1801133, for which Shanghai Biowing Applied Biotechnology Company provided technical support (25). For quality control, 104 samples (12.00%) were randomly reanalyzed, and the accuracy rate was 100% (data not shown). To analyze the regulome DB score, regulomedb.org/ was used, and to analyze the minor allele frequency in Chinese individuals, snpinfo.niehs.nih.gov/snpinfo/snpfunc.htm was used.

Statistical analysis

A t-test was used to compare the age of the cases and controls. A χ² test was used to detect differences in demographic variables, variations between smoking status, history of alcohol consumption, and frequency of the rs1801133 genotype between the cases and controls. A HWE test determined the expected frequency in controls using the standard χ² test. Deviations from HWE in the control group were assessed using an internet-based HWE tool (ihg.gsf.de/cgi-bin/hw/hwa1.pl) (26).

To assess the relationship between the genetic polymorphism and risk of gastric cancer, the odds ratio (OR) and 95% confidence intervals (CIs) were calculated using unconditional logistical regression analysis, and adjusted for age, sex, smoking status and drinking history. Furthermore, genetic polymorphisms were stratified by age, sex, smoking status and drinking history. All statistical analyses was performed using SPSS version 21.0 (IBM Corp.). The data are expressed as the mean ± standard deviation. All P-values are bilateral and P<0.05 was considered to indicate a statistically significant difference.

Results <sec> <title>Characteristics of the study population

As shown in Table I, there were 307 cases and 560 controls included in the present study. There was no statistical difference in age and sex between the cases and the control groups (P=0.218 and 0.067, respectively). The case group contained 185 smokers and 122 nonsmokers. Meanwhile, in the controls, 373 individuals were smokers and 187 were non-smokers. There was a statistically significant difference between the case and the control group (P<0.001). However, there was no statistically significant difference in alcohol consumption (P=0.223).

The genotyping call rate was 100%. In Table II, the genotype distribution of rs1801133 C>T (P=0.112) is shown, which conforms with the HWE (P>0.05). The minor allele frequency (MAF) in the controls is similar to the Chinese MAF in the SNP rs1801133 database (27).

rs1801133 and gastric cancer risk

The frequency of alleles and genotypes, and the associated ORs (95% CI) between cases and controls are shown in Table III. The observed frequency of the rs1801133-T allele in the control group was 43.9%, which was similar to the HapMap frequency of the Han Chinese in Beijing (44.4%). Compared with the control group (44.37%), the frequency of the T allele was significantly reduced (35.83%). The frequency of rs1801133 genotypes was 29.3% (CC), 52.7% (CT), and 18% (TT) in controls, and 41.4% (CC), 45.6% (CT) and 13% (TT) in cases, respectively.

When the rs1801133-CC homozygous genotype was used as the reference group, the CT genotype was associated with risk of gastric cancer (CT vs. CC, OR=0.61, 95% CI=0.45-0.83, P=0.002). The TT genotype was significantly associated with a reduced risk of gastric cancer (TT vs. CC, OR=0.51, 95% CI=0.33-0.79, P=0.002). In the dominant model, rs1801133-TT compared with rs1801133-CC genotype (CT/TT vs. CC, OR=0.59, 95% CI=0.44-0.79, P<0.001) was also associated with a reduced risk of gastric cancer risk. In the recessive model, the TT homozygous genotype was not related to the risk of gastric cancer (CC/CT vs. TT, OR=0.68, 95% CI=0.46-1.01, P=0.681) using the rs1801133-CC/CT genotypes as the reference group (Table III).

After adjustment for age, sex, smoking and drinking status, the TT genotype was associated with a significantly reduced risk of gastric cancer (TT vs. CC, adjusted OR=0.54, 95% 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). Using the rs1801133 CC/CT genotype as the reference group, the TT homozygous genotype was not associated with gastric cancer risk (CC/CT vs. TT, OR=0.71, 95% CI=0.48-1.07, P=0.098).

In order to evaluate the effects of the rs1801133 genotype on the risk of gastric cancer based on sex, smoking, age and alcohol consumption, a hierarchical analysis was performed (Table IV). Compared with the CC genotype, gastric cancer risk in the CT (adjusted OR=0.546, 95% CI=0.377-0.791, P=0.001) and TT (adjusted OR=0.447, 95% CI=0.276-0.823, P=0.008) and CT/TT (adjusted OR=0.525, 95% CI=0.369-0.748, P<0.001) genotype carriers was significantly decreased for male patients. Compared with the CC and CT genotypes, gastric cancer risk in the CT (adjusted OR=0.590, 95% CI=0.378-0.920, P=0.020), TT (adjusted OR=0.369, 95% CI=0.181-0.753, P=0.006), CT/TT (adjusted OR=0.534, 95% CI=0.348-0.818, P=0.004), and CT+CC vs. TT (adjusted OR=0.500, 95% CI=0.259-0.967, P=0.040) genotype carriers was significantly decreased in the younger patients. For older patients, compared with the CC genotype, the risk of gastric cancer was reduced in the CT (adjusted OR=0.601, 95% CI=0.386-0.935, P=0.024) and CT/TT (adjusted OR=0.618, 95% CI=0.408-0.936, P=0.023) genotype carriers. In addition to internal factors, the CT genotype may decrease the risk of gastric cancer (CT vs. CC, adjusted OR=0.411, 95% CI=0.236-0.717, P=0.002; and TT/CT vs. CC, adjusted OR=0.421, 95% CI=0.247-0.718, P=0.001) for those patients who have smoked. Based on alcohol consumption, the CT and TT genotypes may reduce gastric cancer risk (TT/CT vs. CC, adjusted OR=0.673, 95% CI=0.471-0.962, P=0.030) for individuals who drink. The CT and TT genotype may decrease the risk of gastric cancer (CC vs. CT, adjusted OR=0.427, 95% CI=0.226-0.809, P=0.002, and TT/CT vs. CC, adjusted OR=0.437, 95% CI=0.237-0.804, P=0.008) for individuals who never drink.

Discussion

In the present hospital-based case-controlled study on gastric cancer, whether the functional SNP rs1801133 genotypes in the MTHFR gene affected the susceptibility of the Chinese Han population to gastric cancer was assessed in the present study. There was no evidence that rs1801133 TT, CT and TT/CT genotypes were associated with decreased risk of gastric cancer. The rs1801133 C>T polymorphism in the MTHFR gene was negatively associated with the risk of gastric cancer, as well as with age, smoking status and drinking history after correction.

Several studies have not been able to confirm a relationship between the MTHFR C677T genotype and gastric cancer susceptibility. The results of this study are consistent with those of Lin et al (28) and Chen et al (29), although the present study included more cases than the study by Lin et al (28). In the case group, more patients aged 55-63 years, male patients, and patients with a history of smoking and drinking were also enrolled in the present study. The study by Lin et al (28) recruited individuals predominantly from southern China, whereas the present study recruited individuals from eastern China primarily. Therefore, the present study is more relevant for gastric cancer susceptibility in eastern China. However, as the results of the present study and Lin et al (28) were consistent, this highlights the potential generalizability of the results at least regarding the Chinese population.

Single nucleotide polymorphisms of the MTHFR gene are associated with the risk of gastric cancer (30). Chen et al (29) found that MTHFR 677TT was associated with a reduced risk of gastric cancer, which has been confirmed by another study (31). In other studies, several groups reported that carriers of the TT genotype had higher response rates or improved survival rates than the CC or CT genotypes in gastric cancer patients receiving 5-fluorouracil (5-FU) chemotherapy (32,33). Of note, MTHFR polymorphisms have an impact on the efficacy of fluorouracil, as patients with different SNPs have been shown to have different reactivities (34,35). The homozygous genotypes rs2274976-GG and rs1801131-AA were more common in reactive patients, whereas the rs2274976-A allele (GA and AA) and rs1801131-C allele (AC and CC) were more common in unresponsive patients (6). MTHFR polymorphisms may serve an important role in regulating the clinical toxicity and efficacy of 5-FU (36). The C677T SNP may predict toxicity in patients with metastatic colorectal cancer and fluorouracil chemotherapy in Costa Rica (37). However, patients with gastric cancer with CC or CT genotypes tended to have less chemotoxicity than those with the TT genotype. The C677T polymorphism predicted severe chemotoxicity in GC patients receiving 5-FU based chemotherapy, but could not predict efficacy (21). Chen et al (38) found a significant increase in gastric cancer risk in the Asian population. Zintzaras (39) performed study with 1,584 cases and 2,785 controls, and showed that the evidence for association between MTHFR polymorphisms and GC was predominantly present in East Asians and was not significant in Caucasians (39). To further clarify the relationship between the rs1801133 variant of the MTHFR gene and gastric cancer risk, the present case-controlled study using a large sample was performed. Through the analysis of alcohol consumption, sex, age and smoking status, it was shown that male, younger, former smokers and drinkers with the rs1801133 C>T variant had a reduced risk of gastric cancer.

MTHFR polymorphisms are associated with the risk of neurological diseases, psoriasis, various types of cancer, infertility and vascular diseases (40). Folic acid levels are associated with the MTHFR C677T genotype binding and microRNA (miR)-21 expression. miR-21 is a noncoding small RNA that regulates gene expression and is often found in secreted microvesicles (41). Tumor-derived microbubbles induce skeletal muscle cell apoptosis, resulting in a decrease in skeletal muscle quality, which is a characteristic symptom of cancer cachexia (42).

The MTHFR gene produces methylene tetrahydrofolate reductase, a rate-limiting enzyme for folic acid metabolism and DNA methylation, and folic acid is essential to rescue a vulnerable state (43). It is an active 77 kDa protein that catalyzes the transfiguration of 5, 10-methylenetetrahydrofolate to 5-methyltetrahydrofolate (44). There is evidence that MTHFR gene mutations lead to decreased thymidylate synthase (TS) activity in cancer cells, as a consequence of decreased levels of 5, 10-methylenetetrahydrofolate (45); the latter of which supplies the methyl for the methylation of dUMP to dTMP (46). TS is a critical and rate-limiting enzyme for maintaining an appropriate supply of DNA to ensure accurate DNA synthesis and repair (47). Thus, SNPs in the MTHFR gene may contribute to genetic susceptibility to cancer (48).

According to one report, the C>T variant at nucleotide 677 (in exon 4 at the folate-binding site) leads to a valine substitution for alanine, which is functionally relevant, causing a reduction in the activity of MTHFR (19). Studies have shown that individuals who are heterozygous for the rs1801133 polymorphism had 70% of the normal enzyme activity, while carriers of the homozygous polymorphism had only 30% of the normal enzyme activity (47), affecting folate metabolism (49). With regards to the relationship between MTHFR and folate, it has been shown that compound heterozygosity for the 677T allele was associated with reduced plasma folic acid levels (50). Another study found that rs1801133 C>T was related to low plasma folate content and significantly decreased MTHFR activity (51).

The present study has several limitations. Given that the case and control groups were recruited from the hospital, the study population may not represent the average Chinese Han population. Folate status may influence the relationship between the MTHFR SNP rs1801133 and gastric cancer sensitivity. However, no data was available on the intake of folic acid in these subjects, for which a prospective study would be required. Finally, an even larger sample size is required to confirm the results. Further research is required to improve our understanding of the interactions between genes and the environment in the causation of gastric cancer.

In conclusion, the results of the present study showed that the functional MTHFR rs1801133 C>T polymorphism may contribute to the susceptibility of gastric cancer in Chinese Han individuals.

Acknowledgements

We would like to express our gratitude to Dr Wei Zhu for their valuable input. We would also like to thank Dr Mei Wang for assistance with revision of the manuscript.

Funding

This study was supported by funding from the Jiangsu Provincial Key Research and Development Special Fund (grant no. BE2015666) and the Jiangsu Innovative Team Leading Talent Fund (grant no. CXTDC2016006).

Availability of data and materials

The datasets used and/or analyzed during the present study are available from the corresponding author on reasonable request.

Authors' contributions

ZH and HS designed the study. QG acquired the data. QG and ZH wrote the manuscript. ZH and HS performed the experiments. YF and XX analyzed the results. HS and QG edited the manuscript. All authors read and approved the final manuscript.

Ethics approval and consent to participate

The experimental protocol used in the present study was approved by the Ethics Committee for Human Subject study of Jiangsu University (Zhenjiang, China). All patients provided written informed consent.

Patient consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

References 1

Sun

Wang

Chen

Zhao

Shen

Wang

Zhu

Zhao

Gastric cancer mesenchymal stem cells derived IL-8 induces PD-L1 expression in gastric cancer cells via STAT3/mTOR-c-Myc signal axis

Cell Death Dis99282018

30206229

10.1038/s41419-018-0988-9

Potrc

Ivanecz

Krebs

Marolt

Iljevec

Jagric

Outcomes of the surgical treatment for adenocarcinoma of the cardia-single institution experience

Radiol Oncol5265742018

29520207

10.1515/raon-2017-0039

Xin

Wang

Chu

Wang

Zhang

A transcriptomic study for identifying cardia- and non-cardia-specific gastric cancer prognostic factors using genetic algorithm-based methods

J Cell Mol Med24945794652020

32649057

10.1111/jcmm.15618

Nguyen

Mallepally

Hammad

Liu

Thrift

El-Serag

Tan

Prevalence of Helicobacter pylori positive non-cardia gastric adenocarcinoma is low and decreasing in a US population

Dig Dis Sci65240324112020

31728790

Zhang

Bai

Chen

Feng

Yan

Jiang

Zhong

Cheng

Polymorphism of methylenetetrahydrofolate reductase gene is associated with response to fluorouracil-based chemotherapy in Chinese patients with gastric cancer

Chin Med J (Engl)127356235672014

25316230

Bray

Ren

Masuyer

Ferlay

Global estimates of cancer prevalence for 27 sites in the adult population in 2008

Int J Cancer132113311452013

22752881

10.1002/ijc.27711

Wang

Sun

Deng

Feng

Fang

Wang

Liang

Zhou

A novel nomogram individually predicting disease-specific survival after D2 gastrectomy for advanced gastric cancer

Cancer Commun (Lond)38232018

29764518

10.1186/s40880-018-0293-0

Torre

Bray

Siegel

Ferlay

Lortet-Tieulent

Jemal

Global cancer statistics, 2012

CA Cancer J Clin65871082015

25651787

10.3322/caac.21262

Zhang

Zhong

Liu

Wang

Yuan

Wang

Sun

Zhang

Song

Miao

Smoking and COX-2 functional polymorphisms interact to increase the risk of gastric cardia adenocarcinoma in Chinese population

PLoS One6e218942011

21779349

10.1371/journal.pone.0021894

Selhub

Homocysteine metabolism

Ann Rev Nutri192172461999

10448523

10.1146/annurev.nutr.19.1.217

Luo

Muhammad

Chen

Zhang

Song

Associations of the MTHFR rs1801133 polymorphism with coronary artery disease and lipid levels: A systematic review and updated meta-analysis

Lipids Health Dis171912018

30115070

10.1186/s12944-018-0837-y

Jamshidi

Mohammadi Pour

Mahmoudian-Sani

Single nucleotide variants associated with colorectal cancer among Iranian patients: A narrative review

Pharmgenomics Pers Med131671802020

32581566

10.2147/PGPM.S248349

Ozen

Sen

Ozdemir

Methylenetetrahydrofolate reductase gene germ-line C677T and A1298C SNPs are associated with colorectal cancer risk in the Turkish population

Asian Pac J Cancer Prev15773177352014

25292054

10.7314/apjcp.2014.15.18.7731

Zhou

Shan

Wang

The SNP rs4846048 of MTHFR enhances the cervical cancer risk through association with miR-522: A preliminary report

Mol Genet Genomic Med8e10552020

31750632

10.1002/mgg3.1055

De Marchi

Melendez

Laus

Kuhlmann

de Carvalho

Arantes

LMRB

Evangelista

Andrade

de Castro

G Junior

Reis

The role of single-nucleotide polymorphism (SNPs) in toxicity of induction chemotherapy based on cisplatin and paclitaxel in patients with advanced head and neck cancer

Oral Oncol9848522019

31539757

10.1016/j.oraloncology.2019.09.013

Hardi

Melki

Boughaleb

El Harroudi

Aissaoui

Boukhatem

Significant association between ERCC2 and MTHR polymorphisms and breast cancer susceptibility in Moroccan population: Genotype and haplotype analysis in a case-control study

BMC Cancer182922018

29544444

10.1186/s12885-018-4214-z

Xiong

Bian

Lin

Wang

Zhao

Methylenetetrahydrofolate reductase gene polymorphisms in the risk of polycystic ovary syndrome and ovarian cancer

Biosci Rep40BSR202009952020

32639550

10.1042/BSR20200995

Floris

Sanna

Castiglia

Putzu

Sanna

Pazzola

De Miglio

Sanges

Pira

Azara

MTHFR, XRCC1 and OGG1 genetic polymorphisms in breast cancer: A case-control study in a population from North Sardinia

BMC Cancer202342020

32192442

10.1186/s12885-020-06749-w

Le Marchand

Wilkens

Kolonel

Henderson

The MTHFR C677T polymorphism and colorectal cancer: The multiethnic cohort study

Cancer Epidemiol Biomarkers Prev14119812032005

15894672

10.1158/1055-9965.EPI-04-0840

Slattery

Potter

Samowitz

Schaffer

Leppert

Methylenetetrahydrofolate reductase, diet, and risk of colon cancer

Cancer Epidemiol Biomarkers Prev85135181999

10385141

Tang

Jiang

Cheng

Peng

Chen

Cui

Liu

A meta-analysis: Methylenetetrahydrofolate reductase C677T polymorphism in gastric cancer patients treated with 5-Fu based chemotherapy predicts serious hematologic toxicity but not prognosis

J Cancer9105710662018

29581785

10.7150/jca.23391

Zhang

Lin

Jiang

Chen

Tang

Liu

Association between methylenetetrahydrofolate reductase tagging polymorphisms and susceptibility of hepatocellular carcinoma: A case-control study

Biosci Rep39BSR201925172019

31694048

10.1042/BSR20192517

World Medical Association (WMA): WMA Declaration of Helsinki - Ethical Principles for Medical Research Involving Human Subjects. WMA, Ferney-Voltaire, 2018. https://www.wma.net/policies-post/wma-declaration-of-helsinki-ethical-principles-for-medical-research-involving-human-subjects/. Accessed July 9, 2018.

Rohlfs

Weir

Distributions of Hardy-Weinberg equilibrium test statistics

Genetics180160916162008

18791257

10.1534/genetics.108.088005

Hou

Jin

Liu

Wang

Song

UCP2-866G/A polymorphism is associated with prediabetes and type 2 diabetes

Arch Med Res515565632020

32553458

10.1016/j.arcmed.2020.06.001

Sohn

Croxford

Yates

Lucock

Kim

Effect of the methylenetetrahydrofolate reductase C677T polymorphism on chemosensitivity of colon and breast cancer cells to 5-fluorouracil and methotrexate

J Natl Cancer Inst961341442004

14734703

10.1093/jnci/djh015

Tang

Zhang

Qiu

Wang

Sun

Yin

Genetic variations in MTHFR and esophageal squamous cell carcinoma susceptibility in Chinese Han population

Med Oncol319152014

24687778

10.1007/s12032-014-0915-6

Lin

Zeng

Cao

Aberrant DNA methylation of the P16, MGMT, and hMLH1 genes in combination with the methylenetetrahydrofolate reductase C677T genetic polymorphism and folate intake in gastric cancer

Genet Mol Res13206020682014

24737431

10.4238/2014.March.24.10

Chen

Yuan

Duan

Jiang

Zhang

Huang

Xiao

Impact of methylenetetrahydrofolate reductase polymorphisms and folate intake on the risk of gastric cancer and their association with Helicobacter pylori infection and tumor site

Genet Mol Res13971897262014

24615072

10.4238/2014.January.24.2

Application of microarray-based method for methylenetetrahydrofolate reductase (MTHFR) polymorphisms in the risk of gastric carcinoma in east China population

J Nanosci Nanotechnol7324532492007

18019157

10.1166/jnn.2007.693

Galván-Portillo

Oñate-Ocaña

Pérez-Pérez

Chen

Herrera-Goepfert

Chihu-Amparan

Flores-Luna

Mohar-Betancourt

López-Carrillo

Dietary folate and vitamin B12 intake before diagnosis decreases gastric cancer mortality risk among susceptible MTHFR 677TT carriers

Nutrition262012082010

19577428

10.1016/j.nut.2009.05.006

Gao

Sun

Wang

Feng

Relationship of methylenetetrahydrofolate reductase C677T polymorphism and chemosensitivity to 5-fluorouracil in gastric carcinoma

Ai Zheng239589622004

15301724

(In Chinese)

Rozen

Molecular genetics of methylenetetrahydrofolate reductase deficiency

J Inherit Metab Dis195895941996

8892013

10.1007/BF01799831

Custodio

Moreno-Rubio

Aparicio

Gallego-Plazas

Yaya

Maurel

Rodríguez-Salas

Burgos

Ramos

Calatrava

Pharmacogenetic predictors of outcome in patients with stage II and III colon cancer treated with oxaliplatin and fluoropyrimidine-based adjuvant chemotherapy

Mol Cancer Ther13222622372014

24980946

10.1158/1535-7163.MCT-13-1109

Cecchin

Perrone

Nobili

Polesel

De Mattia

Zanusso

Petreni

Lonardi

Pella

D'Andrea

MTHFR-1298 A>C (rs1801131) is a predictor of survival in two cohorts of stage II/III colorectal cancer patients treated with adjuvant fluoropyrimidine chemotherapy with or without oxaliplatin

Pharmacogenomics J152192252015

25331073

10.1038/tpj.2014.64

De Mattia

Toffoli

C677T and A1298C MTHFR polymorphisms, a challenge for antifolate and fluoropyrimidine-based therapy personalisation

Eur J Cancer45133313512009

19144510

10.1016/j.ejca.2008.12.004

Ramos-Esquivel

Chinchilla

Valle

Association of C677T and A1298C MTHFR polymorphisms and fluoropyrimidine-induced toxicity in mestizo patients with metastatic colorectal cancer

Anticancer Res40426342702020

32727753

10.21873/anticanres.14428

Chen

Zhang

Weng

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

Oncol Lett10115911652015

26622644

10.3892/ol.2015.3356

Zintzaras

Association of methylenetetrahydrofolate reductase (MTHFR) polymorphisms with genetic susceptibility to gastric cancer: A meta-analysis

J Hum Genet516186242006

16758123

10.1007/s10038-006-0405-6

Liew

Gupta

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism: Epidemiology, metabolism and the associated diseases

Eur J Med Genet581102015

25449138

10.1016/j.ejmg.2014.10.004

Beckett

Martin

Choi

King

Niblett

Boyd

Duesing

Yates

Veysey

Lucock

Folate status, folate-related genes and serum miR-21 expression: Implications for miR-21 as a biomarker

BBA Clin445512015

26674922

10.1016/j.bbacli.2015.06.006

Calore

Londhe

Canella

Guttridge

Croce

Microvesicles containing miRNAs promote muscle cell death in cancer cachexia via TLR7

Proc Natl Acad Sci USA111452545292014

24616506

10.1073/pnas.1402714111

Vidmar Golja

Smid

Karas Kuzelicki

Trontelj

Gersak

Mlinaric-Rascan

Folate insufficiency due to MTHFR deficiency is bypassed by 5-methyltetrahydrofolate

J Clin Med92020

32887268

10.3390/jcm9092836

Kim

Methylenetetrahydrofolate reductase polymorphisms, folate, and cancer risk: A paradigm of gene-nutrient interactions in carcinogenesis

Nutr Rev582052092000

10941256

10.1111/j.1753-4887.2000.tb01863.x

Tan

Miao

Wang

Xiong

Liang

Sun

Zhou

Zhang

Lin

Significant increase in risk of gastroesophageal cancer is associated with interaction between promoter polymorphisms in thymidylate synthase and serum folate status

Carcinogenesis26143014352005

15817609

10.1093/carcin/bgi090

Chai

Zhang

Geng

Lian

Zhang

Shi

Chen

Genetic association between methylenetetrahydrofolate reductase gene polymorphism and risk of osteonecrosis of the femoral head

Biomed Res Int20151964952015

25688352

10.1155/2015/196495

Jain

Pandey

Tiwary

Jain

MTHFR C677T polymorphism is associated with hyperlipidemia in women with polycystic ovary syndrome

J Hum Reprod Sci552562012

22870016

10.4103/0974-1208.97802

Födinger

Wagner

Hörl

Sunder-Plassmann

Recent insights into the molecular genetics of the homocysteine metabolism

Kidney Int Suppl78S238S2422001

11169018

10.1046/j.1523-1755.2001.59780238.x

Kim

Role of the MTHFR polymorphisms in cancer risk modification and treatment

Future Oncol55235422009

19450180

10.2217/fon.09.26

Bezerra

Oliveira

Soares

Cardoso

Ururahy

Neto

Lima-Neto

Luchessi

Silbiger

Fajardo

Genetic and non-genetic factors that increase the risk of non-syndromic cleft lip and/or palate development

Oral Dis213933992015

25219684

10.1111/odi.12292

Ericson

Ivarsson

Sonestedt

Gullberg

Carlson

Olsson

Wirfält

Increased breast cancer risk at high plasma folate concentrations among women with the MTHFR 677T allele

Am J Clin Nutr90138013892009

19759169

10.3945/ajcn.2009.28064

Table I

Clinicopathological characteristics and risk factors of the patients with in gastric cancer and control group.

	Cases, n=307		Controls, n=560
Variable	n	%	n	%	P-value
Age, years					0.218
≥63	162	52.8	271	48.4
<63	145	47.2	289	51.6
Sex					0.067
Male	223	72.6	373	66.6
Female	84	27.4	187	33.4
Smoking status					<0.001^a
Never	185	60.3	402	71.8
Smoker	122	39.7	158	28.2
Alcohol use					0.223
Never	222	72.3	426	76.1
Drinker	85	27.7	134	23.9

^aP<0.05.

Table II

Primary information of the MTHFR rs1801133 C>T polymorphisms.

Item	Information
Genotyped SNPs	MTHFR rs1801133 C>T
Chromosome	1
Gene Official Symbol	MTHFR
Function	Missense
Chromosome position^a	11778965
Regulome DB Score^b	4
nsSNP	Y
MAF for Chinese in database^c	0.439
MAF in our controls, n=560	0.444
P-value for HWE test in our controls	0.112
Genotyping method	LDR
Genotyping value	100.00%

^aBased on Genome Build version 36.3.

^bBased on regulomedb.org/.

^cBased on snpinfo.niehs.nih.gov/snpinfo/snpfunc.htm. MAF, minor allele frequency; HWE, Hardy-Weinberg equilibrium; LDR, ligation detection reaction; SNP, single nucleotide polymorphism; nsSNP, nonsynonymous single nucleotide polymorphism.

Table III

Logistical regression analyses of the associations between MTHFR rs1801133 C>T polymorphisms and the risk of gastric cancer.

MTHFR rs1801133 C>T genotype	Cases, n (%)	Controls, n (%)	Crude OR (95% CI)	P-value	Adjusted OR^c (95% CI)	Adjusted P-value^c
C	394 (64.2)	623 (55.3)
T	220 (35.3)	497 (44.4)
CC	127 (41.4)	164 (29.3)	1
TT	40(13)	101(18)	0.51 (0.33-0.79)	0.002	0.54 (0.35-0.83)	0.006^a
CT	140 (45.6)	295 (52.7)	0.61 (0.45-0.83)	0.002	0.59 (0.44-0.79)	<0.001^b
CT+TT	180 (58.6)	396 (70.7)	0.59 (0.44-0.79)	<0.001	0.61 (0.44-0.83)	0.001^b
CC+CT	167 (54.4)	265 (47.3)	1
TT	40(13)	295 (52.7)	0.68 (0.46-1.01)	0.681	0.71 (0.48-1.07)	0.098

^aP<0.01,

^bP<0.001.

^cAdjusted for age, sex, smoking status and alcohol consumption. OR, odds ratio; CI, confidence interval.

Table IV

Stratified analyses between MTHFR rs1801133 C>T polymorphism and gastric cancer risk based on sex, age, smoking status and alcohol consumption.

	MTHFR rs1801133 C>T, n, case/control^d				Adjusted^e odd ratio (95% confidence intervals), P-value
Variable	CC	CT	TT	CT+TT	CC	CT	TT	CT+TT	TT vs. CT+CC
Sex
Male	95/107	102/204	26/62	128/266	1	0.546 (0.377-0.791), P=0.001^b	0.447 (0.276-0.823), P=0.008^b	0.525 (0.369-0.748), P<0.001^c	0.677 (0.412-1.114), P=0.125
Female	32/57	38/91	14/39	52/130	1	0.748 (0.420-1.335), P=0.326	0.639 (0.300-1.361), P=0.246	0.717 (0.417-1.234), P=0.230	0.745 (0.378-1.466), P=0.394
Age
<63	64/86	68/152	13/51	81/203	1	0.590 (0.378-0.920), P=0.020^a	0.369 (0.181-0.753), P=0.006^b	0.534 (0.348-0.818), P=0.004^b	0.500 (0.259-0.967), P=0.040^a
≥63	63/78	72/143	27/50	99/193	1	0.601 (0.386-0.935), P=0.024^a	0.681 (0.382-1.215), P=0.193	0.618 (0.408-0.936), P=0.023^a	0.897 (0.534-1.510), P=0.683
Smoking status
Never	72/121	86/201	27/80	113/281	1	0.763 (0.511-1.140), P=0.187	0.621 (0.360-1.072), P=0.087	0.720 (0.492-1.052), P=0.090	0.717 (0.441-1.168), P=0.182
Smoker	55/43	54/94	13/21	67/115	1	0.411 (0.236-0.717), P=0.002^b	0.466 (0.195-1.109), P=0.084	0.421 (0.247-0.718), P=0.001^b	0.803 (0.368-1.753), P=0.582
Alcohol consumption
Never	85/126	105/217	32/83	137/300	1	0.704 (0.483-1.026), P=0.068	0.599 (0.355-1.009), P=0.054	0.673 (0.471-0.962), P=0.030^a	0.732 (0.461-1.160), P=0.184
Drinker	42/38	35/78	08/18	43/96	1	0.427 (0.226-0.809), P=0.009^b	0.486 (0.178-1.325), P=0.159	0.437 (0.237-0.804), P=0.008^b	0.790 (0.312-1.997), P=0.618

^aP<0.05,

^bP<0.01,

^cP<0.001.

^dGenotyping was successful in all cases and control.

^eAdjusted for age, sex, smoking status and alcohol consumption.