title: MTHFR C677T polymorphism interaction with heavy alcohol consumption increases head and neck carcinoma risk.
abstract: MTHFR C677T polymorphism has been indicated to be a risk factor for cancers, but its association with head and neck cancer (HNC) risk remains inconclusive. In the present study, we aimed to get a more precise estimation by performing a quantitative meta-analysis. Published papers up to Jun 2014 was searched and screened. Necessary information was rigorously extracted for data pooling and analyzing, and then, subgroup analyses on ethnicity, source of controls, sample size, tumor type, smoking and drinking status were also carried out. As a result, twenty-three case-control studies including 14298 subjects were included. The overall data failed to reveal a significant association between MTHFR C677T polymorphism and HNC risk (homozygote comparison model: OR = 1.16; 95%CI = 0.93-1.45; dominant model: OR = 1.05; 95%CI =  .90-1.21; recessive model: OR = 1.14; 95%CI = 0.93-1.38). However, in the subgroup analysis about drinking status, increase risk was shown in the heavy drinking subgroup (TT vs CC: OR = 3.11; 95%CI = 1.52-3.02). In conclusion, the results of the present study suggest that Homozygous TT alleles of MTHFR C677T polymorphism might be a risk factor for HNC among individuals who have a heavy drinking history. Further studies are needed to get a more definitive conclusion.
authors.affiliation: Department of Radiation Oncology, Chongqing Cancer Institute, Chongqing, China.
authors.forename: Xianlu
authors.initials: X
authors.lastname: Zhuo
authors.affiliation: Physical Examination Center, Affiliated Hospital of Guiyang Medical College, Guizhou, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Medical Oncology, Chongqing Cancer Institute, Chongqing, China.
authors.forename: Dairong
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Chongqing Cancer Institute, Chongqing, China.
authors.forename: Yongzhong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Gynecologic Oncology, Chongqing Cancer Institute, Chongqing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D000428:Alcohol Drinking / Q000009:adverse effects*; D000483:Alleles; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006258:Head and Neck Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D017594:Publication Bias
chemical_list: C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)