[Folate and cancer].

Folate is one of the important constituents of vegetables and fruits that may provide protection against cancer. An important function of folate is to provide methyl groups required for intracellular methylation reactions and de novo deoxynucleoside synthesis. Therefore, folate deficiency has been thought to be carcinogenic through disruption of DNA methylation, synthesis, and repair. However, to serve as the active mediator, folate requires metabolism catalyzed by several enzymes including methylenetetrahydrofolate reductase (MTHFR), which plays a central role in biotransformation of folate. Thus, it is likely that two functional single nucleotide polymorphisms(677C-->T and 1298A-->C) in the MTHFR gene,both of which diminishes MTHFR activity,may contribute to risk of cancer.