Interactions Between MTHFR C677T - A1298C and Folic Acid Deficiency in Breast Cancers in China

Folate is an important micronutrient found in green vegetables, fruits and beans. The synthetic form that is added to foods and found in supplements is known as folic acid (FA). FA plays an essential role in several complex metabolic pathways including DNA synthesis and pathways that are involved in the methionine metabolic pathway, which is crucial for DNA methylation (Fenech et al., 2001; Eichholzer et al., 2006; Mazz et al., 2010; Bouckaert et al., 2011). FA levels are determined by both dietary FA intake and FA metabolism. FA deficiency induces deficient methylation of deoxyuridylic acid (dUMP) to deoxythymidylic acid (dTMP) leading to uracil misincorporation (Fenech, 2001; Mazz et al., 2010) and DNA global hypomethylation (Rampersaud et al., 2000); this not only leads to point mutations, the generation of singleand double-stranded DNA breaks, chromosome breakage, micronucleus formation and abnormal apoptosis (Everson et al., 1988; Fenech et al., 2001; Fenech et al., 2002; Eichholzer et al., 2006; Yang et al., 2008; Mazz et al., 2010; Bouckaert et al., 2011), but also may