Cattle Virus That Causes Leukemia Triples Breast Cancer Risk In Women

In a first, a new study claims that exposure to bovine leukemia virus (BLV) that causes cancer in cattle could increases risk of breast cancer in women.

Business Standard reports findings of the study published in PLOS ONE. Accordingly, 239 breast cancer tissue samples showed evidence of exposure to BLV. In the study around 59 percent of breast cancer tissue indicated presence of viral DNA as against 29 percent non-cancerous samples with possible exposure to BLV. The study concluded that the risk of having breast cancer could be 3.1 times higher if exposed to BLV.

"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 study lead author Gertrude Buehring, a professor at UC Berkeley's School of Public Health.

 "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 said.

The study cannot conclusively tie human breast cancer and the virus as samples do not tell if study participants were exposed to the virus before or after cancer diagnosis.

BLV is said to spread between cattle but causes disease in only 5 % of the animals. It can spread through infected blood, milk and meat. Pasteurization of milk and proper cooking of meat kills the virus. Until last year, it was not known if the virus could be found in humans.