Polymorphisms and haplotypes in methylenetetrahydrofolate reductase gene and head and neck squamous cell carcinoma risk.

Functional polymorphisms in genes encoding enzymes involved in folate metabolism might modulate head and neck carcinoma risk because folate participates in DNA methylation and synthesis. We therefore conducted a case-control study of 853 individuals (322 head and neck cancer cases and 531 non-cancer controls) to investigate associations among MTHFR C677T and MTHFR A1298C polymorphisms and head and neck squamous cell carcinoma risk. Interactions between these two polymorphisms and risk factors and clinical histopathological parameters were also evaluated. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used to genotype the polymorphisms and Chi-square test and multiple logistic regression were used for statistical analyses. The variables age≥49 years, male gender, tobacco habits and alcohol consumption, MTHFR 1298 AC or CC genotypes, combined genotypes with two or more polymorphic alleles and 677T and 1298C polymorphic alleles were associated with increased risk for this disease (P<0.05). Furthermore, we found that 1298 AC or CC genotypes were associated with age≥49 years, tobacco and alcohol habits (P<0.05). Regarding clinical histopathological parameters, the A1298C polymorphism was more frequent in patients with oral cavity as primary site (P<0.05). MTHFR polymorphisms may contribute for increase risk for head and neck carcinoma and the variables age≥49 years, male gender, tobacco and alcohol habits were associated with MTHFR 1298AC or CC genotypes, confirming that individuals with these variables and MTHFR A1298C polymorphism has higher risk for this disease.