Can Epstein-Barr Virus Increase Breast Cancer Risk?

Epstein-Barr Virus (EBV) might increase the risk of breast cancer, according to experiments with cell lines and mouse xenografts that identified a potential mechanism for the suspected link, published in EBioMedicine.

EBV can infect mammary epithelial cells that express the CD21 receptor, inducing epithelial mesenchymal transition, and triggering the expansion of mammary epithelial-progenitor cells that had stem cell properties, the researchers reported.

EBV infection also hastened breast tumor formation in mice with xenografted mammary epithelial cells.

If confirmed by subsequent studies, the findings might represent a rationale for a vaccination effort to reduce the risk of breast cancer and other EBV-associated cancers.

“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,” speculated senior author Gerburg M. Wulf, MD, PhD, of Beth Israel Deaconess Medical Center, Harvard Medical School, in a press release. “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. While these are subtle changes, they may decades later facilitate breast cancer formation.”

One of eight herpes-family viruses known to infect humans, EBV is believed to infect more than nine in 10 people worldwide. Only a small minority of those infected will develop EBV-associated cancers, like Hodgkin disease, nasopharyngeal carcinoma, gastric adenocarcinoma, or leiomyosarcoma. While previous research has suggested a possible association between EBV infection and breast cancer in some women, it has remained controversial, partly because a molecular mechanism had not been identified, the authors noted.

“The findings further make the case for an EBV vaccine that might protect children from infection and later EBV-associated malignancies,” Dr. Wulf said.