Gene polymorphisms of folate metabolizing enzymes and the risk of gastric cancer.

Multiple studies have reported an association between disturbances of folate metabolism and increased risk of gastric cancer, including low intake of folate, low levels of folate in blood or genetic factors affecting folate metabolism. Among the genetic factors, in particular a common polymorphism in the gene encoding for 5,10-methylenetetrahydrofolate reductase (MTHFR C677T) has been linked to gastric cancer. Other polymorphisms in folate-metabolising genes have been less frequently investigated. Therefore, we analyzed this polymorphism, the glutamate carboxypeptidase (GCP) II C1561T and the reduced folate carrier (RFC) G80A in a case-control study involving 106 patients with histologically confirmed and characterized gastric cancer with adjustment for other established risk factors for gastric cancer in comparison to 106 age- and sex-matched controls. Neither the MTHFR nor the GCP gene polymorphisms showed an association to cancer diagnosis, to tumor stage, grade of differentiation or Lauren type. However, non-cardia cancers were more likely to exhibit the 80GA and 80AA RFC genotypes, compared to cancers of the gastric cardia (adjusted OR 0.28; 95% CI=0.11-0.71). Thus, gene polymorphisms of the RFC gene might contribute to an increased risk of developing distal gastric cancer.