Why alcohol boosts breast cancer risk: study
NEW YORK (Reuters Health) - A study in mice shows that moderate alcohol consumption stimulates the growth and progression of breast cancer by fueling the development of new blood vessels -- a process called "angiogenesis." It does this by boosting expression of a key growth factor known as vascular endothelial growth factor or VEGF.
Drinking alcohol -- even moderate amounts - is a well-established risk factor for breast cancer in women. A recent study found that 60 percent of breast cancer cases in women worldwide were attributable to alcohol consumption. But the mechanism(s) of alcohol-induced breast cancer are poorly understood.
Dr. Jian-Wei Gu and colleagues from the University of Mississippi Medical Center in Jackson examined the effects of alcohol on tumor growth and progression of breast cancer in mice.
For 4 weeks, 6-week old female mice consumed regular drinking water or water containing 1 percent alcohol, which is equivalent to about 2 to 4 drinks in humans. In week 2, the animals were inoculated with mouse breast cancer cells.
"We found after about 4 weeks that breast tumor size almost doubled in mice that drank alcohol compared to control mice given plain water," Gu noted in a telephone interview with Reuters Health. Moderate alcohol intake also caused a noteworthy increase in tumor blood vessels compared with no alcohol intake.
The team also observed a significant increase in VEGF levels in the tumors of mice consuming alcohol compared to the tumors of control mice.
"VEGF can promote the formation of new blood vessels," Gu said. "This suggests that alcohol can induce tumor angiogenesis."
He presented the research at the American Physiological Society's annual meeting, part of Experimental Biology 2007, underway in Washington DC.
What breastcancer.org says about this article…
Why alcohol boosts breast cancer risk: study
Earlier research has shown that drinking alcohol every day can increase breast cancer risk. It's not clear how or why alcohol affects risk. The study reviewed here suggests that in mice, alcohol may promote the growth of a breast cancer by increasing the number of blood vessels that feed the breast cancer. The study also found that levels of a growth factor, VEGF, increased in the mice that were given alcohol. VEGF can stimulate the growth of new blood vessels.
One way cancers grow and thrive in people is by stimulating the growth of new blood vessels in the cancer. Doctors call this new blood vessel growth "angiogenesis." The targeted therapy medicine Avastin works by blocking angiogenesis. Avastin in combination with other medicines has shown promise in treating advanced breast cancer.
We really don't know exactly how much alcohol is safe for breast cancer survivors. But if you want to keep your risk of breast cancer as low as it can be, it makes sense to limit your alcohol consumption. You may even choose to stop drinking alcohol completely. If you do enjoy alcoholic beverages and plan to continue using them, try to have fewer than 5 alcoholic drinks a week. Significant alcohol use is also unhealthy for your liver. And alcohol's effects on the liver may contribute to the link between alcohol and breast cancer. Your liver helps regulate your estrogen levels. Limiting your alcohol may help your liver keep blood estrogen levels low, which also can lower breast cancer risk.
For more information on steps you can take to reduce your breast cancer risk, visit the breastcancer.org Lower Your Risk section.