D. Leon, D. Smith, and G. , Infant mortality, stomach cancer, stroke, and coronary heart disease: ecological analysis, BMJ, vol.320, issue.7251, pp.1705-1711, 2000.
DOI : 10.1136/bmj.320.7251.1705
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC27414

P. Lao-sirieix, C. Caldas, and R. Fitzgerald, Genetic predisposition to gastro-oesophageal cancer, Current Opinion in Genetics & Development, vol.20, issue.3, pp.210-217, 2010.
DOI : 10.1016/j.gde.2010.03.002

C. Stoicov, R. Saffari, X. Cai, C. Hasyagar, and J. Houghton, Molecular biology of gastric cancer: Helicobacter infection and gastric adenocarcinoma: bacterial and host factors responsible for altered growth signaling, Gene, vol.341, pp.1-17, 2004.
DOI : 10.1016/j.gene.2004.07.023

J. Bornschein and P. Malfertheiner, Gastric carcinogenesis. Langenbecks Arch Surg, pp.729-771, 2011.

E. El-omar, M. Carrington, W. Chow, M. Bream, J. Young et al., Interleukin-1 polymorphisms associated with increased risk of gastric cancer, Nature, vol.404, issue.6776, pp.398-402, 2000.
DOI : 10.1038/35006081

J. Zabaleta, Multifactorial Etiology of Gastric Cancer, Methods Mol Biol, vol.863, pp.411-446, 2012.
DOI : 10.1007/978-1-61779-612-8_26

P. Goyette, J. Sumner, R. Milos, A. Duncan, D. Rosenblatt et al., Human methylenetetrahydrofolatereductase: isolation of cDNA, mapping and mutation identification, Nat Genet, 1994.

P. Frosst, H. Blom, R. Milos, P. Goyette, C. Sheppard et al., A candidate genetic risk factor for vascular disease: a common mutation in methylenetetrahydrofolate reductase, Nature Genetics, vol.11, issue.1, pp.111-114, 1995.
DOI : 10.1016/0076-6879(93)17067-F

I. Weisberg, P. Tran, B. Christensen, S. Sibani, and R. Rozen, A Second Genetic Polymorphism in Methylenetetrahydrofolate Reductase (MTHFR) Associated with Decreased Enzyme Activity, Molecular Genetics and Metabolism, vol.64, issue.3, pp.169-72, 1998.
DOI : 10.1006/mgme.1998.2714

L. Stern, J. Mason, J. Selhub, and S. Choi, Genomic DNA hypomethylation, a characteristic of most cancers, is present in peripheral leukocytes of individuals who are homozygous for the C677T polymorphism in the Methylenetetrahydrofolate reductase gene, Cancer Epidemiol Biomarkers Prev, vol.9, pp.849-53, 2000.

B. Blount, M. Mack, C. Wehr, J. Macgregor, R. Hiatt et al., Folate deficiency causes uracil misincorporation into human DNA and chromosome breakage: Implications for cancer and neuronal damage, Proceedings of the National Academy of Sciences, vol.94, issue.7, pp.3290-3295, 1997.
DOI : 10.1073/pnas.94.7.3290

K. Robien and C. Ulrich, 10-methylenetetrahydrofolate reductase polymorphisms and leukemia risk: a HuGE mini review, Am J Epidemiol, vol.5157, issue.7, pp.571-82, 2003.

E. Taioli, M. Garza, Y. Ahn, D. Bishop, J. Bost et al., Meta-and pooled analyses of the Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and colorectal cancer: a HuGE-GSEC Saberi et al, Iran. Biomed. J, 2012.

X. Qi, X. Ma, X. Yang, L. Fan, Y. Zhang et al., Methylenetetrahydrofolate reductase polymorphisms and breast cancer risk: a meta-analysis from 41 studies with 16,480 cases and 22,388 controls, Breast Cancer Research and Treatment, vol.59, issue.6, pp.499-506, 2010.
DOI : 10.1007/s10549-010-0773-7

S. Langevina, D. Lin, K. Matsuo, C. Gao, T. Takezaki et al., Review and pooled analysis of studies on MTHFR C677T polymorphism and esophageal cancer, Toxicology Letters, vol.184, issue.2, 2009.
DOI : 10.1016/j.toxlet.2008.09.003

X. Dong, J. Wu, P. Liang, J. Li, L. Yuan et al., Methylenetetrahydrofolate Reductase C677T and A1298C Polymorphisms and Gastric Cancer: A Meta-analysis, Archives of Medical Research, vol.41, issue.2, pp.125-158, 2010.
DOI : 10.1016/j.arcmed.2010.01.001

M. Mohagheghi, A. Mosavi-jarrahi, R. Malekzadeh, and M. Parkin, Cancer incidence in Tehran metropolis: the first report from the Tehran Population-based Cancer Registry, Arch Iran Med, 1998.

P. Lauren, The two histological main types of gastric carcinoma: diffuse and so-called intestinal-type carcinoma. An attempt at a histological classification, Acta Pathol Microbiol Scand, vol.64, pp.31-49, 1965.

M. Mohammadi, Y. Talebkhan, G. Khalili, F. Mahboudi, S. Massarrat et al., Advantage of using a home-made elisa kit for detection of <i> Helicobacter pylori</i> infection over commercially imported kits, Indian Journal of Medical Microbiology, vol.26, issue.2, pp.127-158, 2008.
DOI : 10.4103/0255-0857.40525

S. Miller, D. Dykes, and H. Polesky, A simple salting out procedure for extracting DNA from human nucleated cells, Nucleic Acids Research, vol.16, issue.3, p.1215, 1988.
DOI : 10.1093/nar/16.3.1215

Y. Wang, W. Guo, Y. He, Z. Chen, D. Wen et al., Association of MTHFR C677T and SHMT1 C1420T with susceptibility to ESCC and GCA in a high incident region of Northern China, Cancer Causes & Control, vol.5, issue.2, pp.143-52, 2007.
DOI : 10.1007/s10552-006-0097-4

V. De-re, R. Cannizzaro, V. Canzonieri, E. Cecchin, L. Caggiari et al., MTHFR polymorphisms in gastric cancer and in first-degree relatives of patients with gastric cancer, Tumor Biology, vol.121, issue.1, pp.23-32, 2010.
DOI : 10.1007/s13277-009-0004-1

A. Rashid and J. Issa, CpG island methylation in gastroenterologic neoplasia: A maturing field, Gastroenterology, vol.127, issue.5, pp.1578-88, 2004.
DOI : 10.1053/j.gastro.2004.09.007

T. Tahara, T. Shibata, M. Nakamura, H. Yamashita, D. Yoshioka et al., MTHFR 677T Carrier Influences the Methylation Status of H. Pylori-Infected Gastric Mucosa in Older Subjects, Digestive Diseases and Sciences, vol.16, issue.11, pp.2391-2399, 2009.
DOI : 10.1007/s10620-008-0624-0

S. Hercberg and P. Galan, Nutritional anaemias, Bailli??re's Clinical Haematology, vol.5, issue.1, pp.143-68, 1992.
DOI : 10.1016/S0950-3536(11)80039-9

L. Wroblewski, R. Peek, . Jr, and K. Wilson, Helicobacter pylori and Gastric Cancer: Factors That Modulate Disease Risk, Clinical Microbiology Reviews, vol.23, issue.4, pp.713-752, 2010.
DOI : 10.1128/CMR.00011-10
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952980

L. Coussens and Z. Werb, Inflammation and cancer, Nature, vol.2, issue.6917, pp.860-867, 2002.
DOI : 10.1006/cyto.1996.0074

J. Salgueiro, M. Zubillaga, C. Goldman, A. Barrado, M. Martinez-sarrasague et al., Review article: is there a link between micronutrient malnutrition and Helicobacter pylori infection? Aliment Pharmacol Ther, pp.1029-1063, 2004.

N. Filho, E. Alves, M. Lima, V. Rabenhorst, and S. , MTHFR C677T polymorphism and differential methylation status in gastric cancer: an association with H. pylori infection. Virchows Arch, pp.627-660, 2010.

F. Zhang, M. Terry, L. Hou, J. Chen, J. Lissowska et al., Genetic Polymorphisms in Folate Metabolism and the Risk of Stomach Cancer, Cancer Epidemiology Biomarkers & Prevention, vol.16, issue.1, pp.115-136, 2007.
DOI : 10.1158/1055-9965.EPI-06-0513

T. Gotze, C. Rocken, F. Rohl, T. Wex, J. Hoffmann et al., Gene polymorphisms of folate metabolizing enzymes and the risk of gastric cancer, Cancer Letters, vol.251, issue.2, pp.228-264, 2007.
DOI : 10.1016/j.canlet.2006.11.021

C. Walmsley, C. Bates, A. Prentice, and T. Cole, Relationship between cigarette smoking and nutrient intakes and blood status indices of older people living in the UK: further analysis of data from the national diet and nutrition survey of people aged 65 years and over, Public Health Nutr, vol.2, issue.2, pp.95199-208, 1994.

D. Mannino, J. Mulinare, E. Ford, and J. Schwartz, Tobacco smoke exposure and decreased serum and red blood cell folate levels: Data from the Third National Health and Nutrition Examination Survey, Nicotine & Tobacco Research, vol.5, issue.3, pp.357-62, 2003.
DOI : 10.1080/1462220031000094330

P. Ueland, S. Hustad, J. Schneede, H. Refsum, and S. Vollset, Biological and clinical implications of the MTHFR C677T polymorphism, Trends in Pharmacological Sciences, vol.22, issue.4, pp.195-201, 2001.
DOI : 10.1016/S0165-6147(00)01675-8

M. Lacasana-navarroa, M. Galvan-portilloa, J. Chenb, M. López-cervantes, and L. López-carrillo, Methylenetetrahydrofolate reductase 677C>T polymorphism and gastric cancer susceptibility in Mexico, European Journal of Cancer, vol.42, issue.4, pp.528-561, 2006.
DOI : 10.1016/j.ejca.2005.10.020

M. Hosseini, M. Houshmand, and A. Ebrahimi, MTHFR polymorphisms and breast cancer risk, Archives of Medical Science, vol.1, issue.1, pp.134-141, 2011.
DOI : 10.5114/aoms.2011.20618
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3258688

P. Fard-esfahani, A. Fard-esfahani, P. Saidi, S. Fayaz, R. Mohabati et al., An increased risk of differentiated thyroid carcinoma in Iran with the 677C???T homozygous polymorphism in the MTHFR Gene, Cancer Epidemiology, vol.35, issue.1, pp.56-64, 2011.
DOI : 10.1016/j.canep.2010.10.001

M. Safarinejad, N. Shafiei, and S. Safarinejad, Relationship between three polymorphisms of methylenetetrahydrofolate reductase (MTHFR C677T, A1298C, and G1793A) gene and risk of prostate cancer: A case-control study, The Prostate, vol.29, issue.6, pp.1645-57, 2010.
DOI : 10.1002/pros.21200