Alcohol
en borstkanker.*
Voor het eerst hebben wetenschappers in het laboratorium de ontwikkeling van borstkanker als gevolg van alcohol goed in kaart kunnen brengen. Steeds meer studies de laatste tijd tonen aan dat alcoholconsumptie de kans op borstkanker flink kan verhogen. In deze studie kregen muizen of alleen water of water met een beetje alcohol, vergelijkbaar voor een mens 2 glazen per dag. Aan het eind van de studie bleek in de alcoholgroep de tumor bijna 2x zo groot en de aanmaak van nieuwe bloedvaatjes 30% hoger te zijn dan in de groep met alleen water.
New
Animal Study May Explain Why Alcohol Consumption Increases Breast Cancer Risk
For
the first time, scientists have used a laboratory mouse model to mimic the
development of human alcohol-induced breast cancer. The results are part of a
new study, Chronic Alcohol Consumption Increases Tumor Growth and
Amgiogenesis of Breast Cancer in Female Mice, conducted by Brandi Busby, Wei
Tan, Jordan Covington, Emily Young, and Jian-Wei Gu, all of the University of
Mississippi Medical Center, Department of Physiology and Biophysics, University
of Mississippi Medical Center, Jackson, MS. Dr. Gu will present the team's
findings in detail during the American Physiological Society (APS; www.The-APS.org)
annual meeting, which is being held as part of the Experimental Biology (EB '07)
meeting. More than 12,000 scientists are attending the conference, being held at
the Washington, DC Convention Center.
Background
Alcohol (EtOH) consumption - even moderate - is a well-established risk factor
for breast cancer in women. A recent study showed that 60 percent of female
breast cancers worldwide were attributable to alcohol consumption. Nevertheless,
the mechanisms of alcohol-induced breast cancer are poorly understood.
The definitive biological effects and molecular mechanisms of EtOH on
progression and malignancy of breast cancer have not been investigated using a
mammalian breast cancer model that mimics the human disease. Scientists have
suggested that the possible mechanisms involved include the agitation of
estrogen metabolism and response; cell mutation by the EtOH metabolite
acetaldehyde; oxidative damage; and one-carbon metabolism pathways through
reduced folic acid.
Methodology
To date, there has not been an animal model that faithfully mimics the human
disease with respect to characteristics of breast cancer, immunocompetence, and
physiologically relevant EtOH intake. The researchers addressed and overcame the
obstacles and developed a novel mouse breast cancer model. The model mimics
human breast cancer disease in which the estrogen receptor-positive breast
adenocarcinoma cells were subcutaneously injected near the pad of the fourth
mammary gland of female immunocompetant mice (C57BL/6). The six-week-old female
mice were fed with moderate EtOH (one percent in drinking water) for four weeks,
the equivalent of two drinks per day in humans. The control mice received
regular drinking water only.
In the second week of the experiment, mouse breast cancer cells (5x105 E0771)
were injected at cite referenced above. At the end of the experiment, the tumors
were isolated to measure tumor size, examine intratumoral microvessel (IM)
density via CD 31 immunohistochemistry staining, and assessing VEGF protein
levels via ELISA. These steps were taken to determine the effects of EtOH intake
in physiologically relevant doses on tumor growth and angiogenesis in mouse
breast cancer.
Results
The researchers found:
-- that moderate alcohol consumption significantly increased the tumor size of
breast cancer in mice, which was a 1.96-fold increase in tumor weight vs.
control mice;
-- that alcohol intake caused a 1.28-fold increase in tumor microvessel density
vs. the control group;
-- a significant increase in tissue protein levels of VEGF were found in the
tumors of the mice treated with EtOH vs. control group;
-- EtOH intake did not cause significant changes in the body weight of the mice.
Conclusions
This study presents the first animal model to confirm that alcohol consumption
stimulates tumor growth and malignancy of breast cancer, and reveals some of the
mechanisms of alcohol-induced breast cancer. The findings demonstrate that even
moderate alcohol consumption significantly stimulates tumor growth of breast
cancer and that induction of tumor angiogenesis and VEGF expressions are
mechanisms which are associated with the progression of this deadly disease.
The American Physiological Society (APS) has been an integral part of the
scientific discovery process since it was established in 1887. Physiology is the
study of how molecules, cells, tissues and organs function to create health or
disease.
(Juni 2007)