A diet high in sucrose and carbohydrates does not appear to increase the risk of pancreatic cancer, according to a new study in the September 4 issue of the Journal of the National Cancer Institute. However, the study did find that impaired glucose metabolism may play a role in the development of pancreatic cancer.
Obesity and diabetes have been associated with an increased risk of pancreatic cancer. To determine whether sugar and carbohydrate intake affect this risk, Dominique Michaud, Sc.D., of the National Cancer Institute, Charles S. Fuchs, M.D., of the Dana-Farber Cancer Institute, and their colleagues tracked the eating habits and incidence of pancreatic cancer among 88,802 women in the Nurses' Health Study.
After 18 years of follow-up, the researchers found no association between carbohydrate and sucrose intake and the overall risk of pancreatic cancer. However, among women who were overweight or more sedentary, diets high in fructose and glycemic load (a quantitative measure of a diet's effect on blood glucose levels) were associated with an increased risk of pancreatic cancer.
The authors conclude that a diet high in glycemic load may increase the risk of pancreatic cancer in women who already have an underlying degree of insulin resistance.
Contact: Bill Schaller, Dana-Farber Cancer Institute, 617-632-5357, william_schaller@dfci.harvard.edu
Study Finds No Association Between Intake of Dairy Products and Breast Cancer Risk
Among postmenopausal women, consumption of dairy products is not associated with a reduced risk of breast cancer, according to a study in the September 4 issue of the Journal of the National Cancer Institute. However, among premenopausal women, consumption of low-fat dairy products may be associated with a modest reduction in breast cancer risk.
Myung-Hee Shin, MD, Ph.D., and Walter C. Willett, M.D., Dr.P.H., of the Harvard School of Public Health, and their colleagues examined the association between breast cancer risk and intake of dairy products, calcium, and vitamin D among 88,691 participants in the Nurses' Health Study.
After 16 years of follow-up, the authors found no association between intake of dairy products and risk of breast cancer among postmenopausal women. In premenopausal women, however, high intakes of dairy products, especially low-fat dairy foods and skim/low-fat milk, was associated with a modest reduction in the risk of breast cancer.
Contact: Jeff Ventura, Brigham and Women's Hospital, 617-534-1605, jventura@partners.org
Natural Compounds Trigger Tumor Cell Death
New research provides insight into how a natural compound found in hot chili peppers makes tumor cells commit suicide. The work is described in the September 4 issue of the Journal of the National Cancer Institute.
According to Numsen Hail, Jr. and Reuben Lotan, Ph.D., of the University of Texas M. D. Anderson Cancer Center in Houston, capsaicin, and a related compound called resiniferatoxin, cause tumor cells to self-destruct by starving them of oxygen. Capsaicin and resiniferatoxin are natural compounds known as vanilloids.
The researchers exposed human skin cancer cells to capsaicin and resiniferatoxin and found that a majority of the cells died. The process was associated with an increase in permeability of the inner mitochondrial membrane and a decrease in oxygen consumption. These findings suggest that vanilloids may be useful for preventing or treating skin cancers.
Contact: Laura Sussman, M. D. Anderson Cancer Center, 713-745-2457, lsussman@mdanderson.org
Macrophage Activating Factor Shown to Have Antiangiogenic Effect
A macrophage activating factor called GcMAF can stimulate macrophages, or a type of white blood cell, to attack tumor cells. A new study has found that, in addition to its ability to activate macrophages, GcMAF also has direct antiangiogenic effects on endothelial cells. The results appear in the Sept. 4 issue of the Journal of the National Cancer Institute.
Shigeru Kanda, M.D., Ph.D., of the Nagasaki University Graduate School of Medicine, found that, in vitro, GcMAF (the vitamin D3-binding protein [Gc protein]-derived macrophage activating factor) inhibited different characteristics of angiogenesis, including endothelial cell proliferation, chemotaxis, and tube formation that were stimulated by growing cells in the presence of various angiogenic stimulants (fibroblast growth factor-2 [FGF-2], vascular endothelial growth factor-A, or angiopoietin 2). They also noted that GcMAF inhibited angiogenesis induced by fibroblast growth factor-2 in vivo.
By using monoclonal antibodies against CD36, a receptor for the antiangiogenic factor thrombospondin-1, the authors found that the antiangiogenic activity of GcMAF could be blocked. The authors conclude that, in addition to its ability to activate tumoricidal macrophages, GcMAF has direct antiangiogenic effects on endothelial cells that may be mediated through the CD36 receptor.
Gene Amplification May Manifest as Aggressive Bladder Cancers
Amplification of the STK15 gene appears to be associated with more aggressive bladder cancers, according to new research in the September 4 issue of the Journal of the National Cancer Institute. Subrata Sen, Ph.D., Bogdan Czerniak, MD, Ph.D., and their colleagues at the University of Texas M. D. Anderson Cancer Center examined the STK15 gene in 61 human bladder tumor samples and found that tumors expressing high levels of the STK15 gene were associated with an increased rate of metastases and decreased patient survival compared with tumors expressing low levels of the gene.
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JNCI Journal of the National Cancer Institute