Women infected with the Epstein-Barr virus (EBV) may face an increased risk for developing breast cancer.

That’s the latest word from a study published online in the journal EBioMedicine that health specialists say has important implications for breast cancer screening and prevention.

EBV, one of eight known viruses in the herpes family to infect humans, is one of the most common viruses and is best known as the cause of infectious mononucleosis.
More than 90 percent of the world's population carries EBV, and most individuals experience no effects from infection.

But in certain individuals, EBV has been linked to various cancers, including African Burkitt lymphoma, Hodgkin's disease, nasopharyngeal carcinoma, gastric adenocarcinoma, and leiomyosarcoma.

For the latest study, Dr. Gerburg Wulf — a physician at Beth Israel Deaconess Medical Center and an associate professor of Medicine at Harvard Medical School — cultured breast cells in the presence of EBV. The experiments showed EBV causes the cells to take on characteristics of stem cells and tumors, which can keep dividing.

When the breast cells were implanted into mice, EBV accelerated the formation of breast cancer, Wulf’s team found.

"We think that if a young woman develops EBV during her teenage years or later, her breast epithelial cells will be exposed to the virus and can be infected. While for most individuals, there will be no long-term consequences, in some the infection may leave genetic scars and change the metabolism of these cells," explained Wulf. "While these are subtle changes, they may, decades later, facilitate breast cancer formation.

"The findings further make the case for an EBV vaccine that might protect children from infection and later EBV-associated malignancies."