Epstein-Barr virus has been detected in breast cancer tissue and tumor cells and may impact the efficiency of chemotherapeutic drug treatment, say researchers from France and Japan. They report their findings in the Journal of Virology.

A ubiquitous human herpes virus, the Epstein-Barr virus (EBV), has been previously linked to skin and gastric cancer, as well as cancer of the salivary glands and thymus. New studies have detected EBV in breast cancer specimens and have prompted researchers to examine the effect of infection with EBV on anticancer drug treatment.

In the study, biopsy specimens of breast cancer tissue and tumor cells were tested for the EBV genome. The genome was identified in about half of the specimens; however, the viral load was highly variable from tumor to tumor. These findings indicate that although EBV isn't likely to cause breast cancer, it may contribute to tumor progression. In addition, researchers studied the EBV infected cells in vitro and found that the virus may contribute to the resistance of paclitaxel (taxol), chemotherapy commonly used in the treatment breast cancer, and cause overexpression of the multidrug resistance gene (MDRI).

"Consequently, even if a small number of breast cancer cells are EBV infected, the impact of EBV infection on the efficiency of anticancer treatment might be of importance," say the researchers.

SOURCES:
Journal of Virology, January 2006
American Society of Microbiology (http://www.asm.org)