Many risk factors for breast cancer, including genetics, age, reproductive history and lifestyle, may increase a woman’s chances for getting this very serious disease. However, this study shows that bovine leukemia virus, or BLV, when transmitted to humans, may make women three times more likely to develop breast cancer than women who don’t carry this bovine disease.
The study, published in September 2015 in PLOS ONE, examined breast tissue from 239 donors over the six years from 2002 to 2008. Researchers noted that the frequency of BLV DNA in mammary tissue was prevalent in 59 percent of women with breast cancer versus just 29 percent for those who never developed this cancer. Scientists took into account other risk factors for breast cancer when measuring these odds.
What Does This Mean?
The results are startling in terms of a possible new cause for breast cancer, notes UC Berkeley. The risk factor for BLV is greater than that of more common risk factors, including obesity, alcohol and using hormones past menopause. The good news is that scientists may develop a new way to help prevent one possible cause of breast cancer.
The link between a virus and getting cancer is not a novel idea in medical science. The virus that causes hepatitis B can cause liver cancer. The human papillomavirus can cause cervical and anal cancers. Doctors and health care experts use vaccines for these viruses to prevent their associated cancers.
The BLV study’s lead author Gertrude Buehring pointed out that their results do not prove that the virus causes cancer, but its correlation as a risk factor is too great to ignore. Scientists must try to figure out when these women got the virus and whether it was before or after getting breast cancer. Researchers need to determine exactly how humans become infected with BLV, a disease that normally only infects cattle.
How Do Humans Get BLV?
Scientists aren’t sure how humans get BLV DNA in their bodies; however, consuming unpasteurized milk or undercooked beef may cause the virus to appear in human tissue. Other humans, such as farmers who come in contact with the cows, may transmit the virus to another human through common contact. Cows transmit the disease among themselves through blood, semen, saliva and milk. Just 1 to 5 percent of cows that test positive for BLV DNA develop full-blown leukemia.
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A 2007 report from the U.S. Department of Agriculture found that 100 percent of dairy operations with 500 or more head of cattle tested positive for BLV in bulk milk tanks. In small herds of less than 100 cattle, BLV appeared in 83.2 percent of their test samples. Overall, 83.9 percent of dairy operations found BLV, and nearly 80 percent of U.S. dairy operations participated in this massive study.
The figures reconfirm a 1996 study that stated a majority of dairy operations spread BLV among cows. Farmers can prevent the spread of BLV by using new needles for each injection, sterilizing equipment that comes in contact with cows, and feeding calves pasteurized milk and colostrum. Culling specimens that have BLV is not cost effective for dairy farmers, so preventing the spread of BLV represents the way to go with respect to keeping BLV away from humans.
What Can Women Do?
If scientists find a viral link to breast cancer through BLV, women can take steps to prevent BLV DNA from entering their bodies. One way to try to prevent getting this disease includes eating clean food. For meats, this means eating foods raised without antibiotics. One crucial step to eating clean beef and dairy involves consuming pasteurized milk and fully cooked beef. A healthy diet is already essential to good health in general and could prevent some types of cancer as well.The link between BLV and breast cancer needs much more study to find conclusive evidence of a possible risk factor.
Discover more ways to eat healthy with breast cancer on The Breast Cancer Site.