Relation between the SNPs in Methylenetetrahydrofolate Reductase Gene C677T and G1793A and the Susceptibility of Sporadic Breast Cancer

To investigate the relation between C677T and G1793A site SNPs(Single nucleotide polymorphisms) of methylenetetrahydrofolate reductase(MTHFR) gene and the susceptibility of sporadic breast cancer,the polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) method was used to analyze the SNPs of MTHFR C677T and G1793A in 200 breast cancer patients and 200 control volunteers,and the logistic regression analysis was performed to investigate the association between different genotypes and susceptibility of breast cancer.The results showed that,the frequency of MTHFR 677TT genotype in the breast cancer group was 25.00%,which was significantly higher than 10.50% in the controls(X2=14.401,P=0.001);The frequency of MTHFR 677CT genotype was 44.50%,which was lower than 54.50% in the controls;the frequency of MTHFR 677CC genotype was similar in both the cases and the controls;and the frequency of MTHFR 1793GA genotype was 18.50%,which was evidently higher than 8.50% in the controls(X2=8.563,P=0.003).The allele frequencies of MTHFR 677T and 1793A in the breast cancer patients were 47.25% and 9.25%,respectively,which were significantly greater than 37.75% and 4.25% in the controls.For MTHFR C677T,the MTHFR 677TT genotype was found to be at a significant 2.732-fold increased risk of developing breast cancer(95% CI=1.418~5.051,P=0.001),compared with that in the referent group carrying the MTHFR 677CC genotype.For MTHFR G1793A,the MTHFR1793GA genotype was found to be at a significant 2.444-fold increased risk of developing breast cancer(95% CI=1.325~4.505,P=0.004),compared with the referent group carrying the MTHFR 1793GG genotype.Besides,the polymorphism of MTHFR C677T gene in the breast cancer group was associated with the tumor size(x2=7.431,P=0.024),while the polymorphism of MTHFR G1793A gene was associated with lymph node metastasis(x2=8.939,P=0.011) and cancer histological grading(x2=9.983,P=0.007).The polymorphism of MTHFR genes C677T and G1793A is correlated with the susceptibility of sporadic breast cancer.