Breast cancer risk higher with presence of cattle leukemia virus: study

The presence of bovine leukemia virus in women's breast tissue could increase the likelihood of breast cancer.

In a study published in the journal PLOS ONE, researchers found that in the 239 breast cancer tissue donate by women, nearly 60 percent of the breast cancer cells had bovine leukemia virus (BLV). However, in the breast tissue samples from women with no breast cancer, the BLV exposure was only 29 percent.

Further comparison and analysis enabled the researchers to determine that breast cancer risk is 3.1 times higher if BLV is present in women. The researchers found the discovery surprising as the BLV exposure is higher than the other risk factors of breast cancer.

"This odds ratio is higher than any of the frequently publicized risk factors for breast cancer, such as obesity, alcohol consumption and use of post-menopausal hormones," said Gertrude Buehring, lead author of study from Berkeley's School of Public Health, in a press release.

According to the report by News Everyday, the findings of the study cannot confirm that BLV directly causes breast cancer because the tissue samples cannot be examined if they have been exposed to BLV prior to their breast cancer diagnosis.

"The association between BLV infection and breast cancer was surprising to many previous reviewers of the study, but it's important to note that our results do not prove that the virus causes cancer," Buehring explained.

Buehring added that if further studies conducted found BLV to be the culprit behind breast cancer, it could open up new treatment methods for the disease.

"If BLV were proven to be a cause of breast cancer, it could change the way we currently look at breast cancer control," said Buehring in a report by UPI. "It could shift the emphasis to prevention of breast cancer, rather than trying to cure or control it after it has already occurred."

According to Medical News Today, it was only discovered in 2014 that the transmission of BLV to humans is possible. BLV is a retrovirus and can cause infected cattle to develop malignant lymphoma and lymphosarcoma. Infected animals that have been exposed to BLV usually have virus antibodies in their milk of serum. The outlet added that it is unclear how BLV virus shows up in breast tissue, Buehring states that it may be through uncooked meat, drinking unpasteurized milk or spread from another person.

Breast cancer is the most common cancer among US women and leading cause of death among Hispanic women. According to the Centers for Disease Control and Prevention, 224,147 women and 2,125 men in the country were diagnosed with breast cancer in 2012.