The nutrients folate and vitamin B6 may help reduce the risk of developing breast cancer, according to a study in the March 5 issue of the Journal of the National Cancer Institute.
Past epidemiologic studies have suggested that folate intake may reduce the increased risk of breast cancer associated with moderate alcohol consumption. However, there is limited data on the relationship between plasma folate levels and breast cancer risk.
Shumin M. Zhang, M.D., Sc.D., of the Harvard School of Public Health, and colleagues examined intake and plasma levels of folate, vitamin B6, vitamin B12, and homocysteine among 712 patients with breast cancer and 712 control subjects without breast cancer who were participating in the Nurses' Health Study.
The authors found that higher plasma folate levels were associated with lower risk of breast cancer and that this association was particularly strong among women who consumed moderate amounts of alcohol (at least 15 g/day or 1 drink/day). Higher plasma vitamin B6 levels were also found to be associated with breast cancer risk. Plasma vitamin B12 levels were inversely associated with breast cancer risk, but only among premenopausal women.
Contact: Amy Dayton, Brigham and Women's Hospital, 617-534-1600, adayton2@partners.org
Risk of Digestive Cancers Elevated Among Patients with Cystic Fibrosis
Patients with cystic fibrosis, particularly those who have undergone an organ transplantation, may have an increased risk of digestive tract cancers, according to a study in the March 5 issue of the Journal of the National Cancer Institute.
Because more patients with cystic fibrosis are reaching adulthood, lung and other organ transplantations among these patients is increasing. However, aging and organ transplantion are two factors associated with increased cancer risk.
To compare the risk of cancer among transplant and nontransplant patients with cystic fibrosis, Patrick Maisonneuve, of the European Institute of Oncology, Milan, and Albert B. Lowenfels, M.D., of the New York Medical College, Valhalla, and their colleagues examined 28,858 patients with cystic fibrosis over a period of 10 years and found a greater than expected number of digestive cancers--particularly cancers of the small bowel, colon, and biliary tract--among these patients. However, the increased risk appeared to be more pronounced in patients who had undergone an organ transplantation.
Contact: Susan Hoffner, New York Medical College, 914-594-4536, susan_hoffner@nymc.edu
Plasmogen Activator and Captopril Increase Antiangiogenic Activity of Plasma
Human plasma is rich in molecules that can regulate angiogenesis, or the formation of new blood vessels. A study in the March 5 issue of the Journal of the National Cancer Institute has found that the overall antiangiogenic activity of human plasma may be increased by treatment with recombinant t-PA and captopril, and that this activity is independent of the antiangiogenic molecule angiostatin. Jaime Merchan, M.D., and Vikas P. Sukhatme, M.D., Ph.D., of the Beth Israel Deaconess Medical Center in Boston, and their colleagues showed that mice treated with rt-PA and captopril had substantially reduced angiogenic activity compared with untreated control mice. In tests on three cancer patients, antiangiogenic activity in the plasma was higher after the patients were treated with rt-PA and captopril than it was before treatment. The authors noted that the antiangiogenic activity of plasma remained even after the removal of angiostatin, suggesting that the antiangiogenic effects are independent of angiostatin.
Oral Drug Reactivates Silenced Genes
A new drug called zebularine, which can be administered orally, may help reactivate genes that have been silenced by methylation, concludes a study in the March 5 issue of the Journal of the National Cancer Institute.
The silencing of genes, particularly tumor suppressor genes, by methylation is associated with cancer. Silenced genes can be reactivated by methylation inhibitors such as 5-azacytidine, but these inhibitors are toxic and cannot be given orally. New demethylating agents, such as zebularine, are thus being studied.
Jonathan C. Cheng and Peter A. Jones, Ph.D., D.Sc., of the University of Southern California/Norris Comprehensive Cancer Center and Hospital in Los Angeles, and their colleagues found that zebularine inhibited DNA methylation, reactivated genes previously silenced by methylation, and had minimal cytotoxicity in both laboratory and animal experiments. Tumors in mice treated orally with zebularine shrunk significantly compared with tumors in control mice.
Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.
Journal
JNCI Journal of the National Cancer Institute