The link between sexually transmitted infection Human Papillomavirus (HPV) and breast cancer has been strengthened by a new Australian study showing the virus gene sequences to be active in some breast cancers.
The research, while not conclusive, has implications for women who have had HPV, as they could be at higher risk of developing some breast cancers and at younger ages.
It also provides hope, however, as vaccines can be created for viruses, potentially leading the way to the eradication of some breast cancers.
University of NSW Emeritus Professor James Lawson told The Huffington Post Australia the new research set to fill in gaps of understanding about viruses and some breast cancers.
"We confirmed women who had have previous cervical HPV-related pathology -- including pre cancer of the cervix -- those young women have a greater-than-expected proportion to develop HPV-related breast cancer," he told HuffPost Australia.
"We also found the identical virus in both the cervix and the breast, and that’s a very significant observation because there's an implication that it is almost certainly the same virus hanging around inside a woman, for maybe 10, 20 or more years.
Previous research showed HPV appeared to be able to travel from the cervix into other parts of the body through white blood cells.
"It also showed that women with HPV-positive breast cancer are significantly younger than the average age of all women with breast cancer -- nearly 10 years younger," Lawson said.
"The implication is pretty sensitive but important because young, modern women are more sexually active than previous generations, hence will have a much higher rate of HPV cervical infections."
Lawson said more research needed to be done to understand how HPV spread in the body and to confirm it did in fact cause cancer in other areas of the body.
"It shows HPV is one of a key handful of viruses that are beginning to look more and more as if they are the underlying cause of breast cancer," he said.
The research was funded by the National Breast Cancer Foundation.
As for continuing research, Lawson, who is 82 and has been collaborating with colleagues in their 70s, said it was a contentious area of science and more young people needed to get involved.
"Who would’ve thought breast cancer is an infectious disease?" he said.
"There aren't many young people studying it and we have a theory why: It is difficult. It is not accepted. People don’t believe it, and therefore young people at the start of their careers are less likely to take a risk. They are thinking about their career.
"I'm 82, I have nothing to lose."