An increased risk of differentiated thyroid carcinoma in Iran with the 677Ca'T homozygous polymorphism in the MTHFR Gene

Background: Methylenetetrahydrofolate reductase (MTHFR) involves in folic acid metabolism which influences DNA methylation. A single nucleotide polymorphism (SNP) called 677Ca'T in MTHFR gene causes producing a thermolabile enzyme with reducing function and eventually defects DNA methylation. To determine association between germ-line polymorphism in MTHFR gene with differentiated thyroid carcinoma (DTC), this preliminary study was designed. Methods: This was a case-control study of 154 DTC patients and 198 cancer free individuals. Genotyping was performed by a multiplex PCR method and the frequencies of the 677Ca'T SNP in cases and controls were compared. The risk estimation was done by multivariate logistic regression analysis. Results: Compared to CC genotype, an increased risk of DTC for the 677Ca'T homozygous genotype was demonstrated (odds ratio [OR]: 2.08, 95% confidence interval [CI]: 0.82-5.25). Also, multivariate analysis demonstrated an increased risk of DTC in recessive fashion (TT vs. CC or CT) (OR: 2.38, 95% CI: 0.97-5.82). Conclusion: The MTHFR 677Ca'T homozygous variant allele may be associated with increased risk of DTC.