Human Breast Tumor Cells Support Productive HCMV Infection

Breast cancer is the leading cause of cancer deaths among women. While many risk factors for breast cancer are known, viral infection has emerged as a potential factor in tumor development. Human Cytomegalovirus (HCMV) generally causes mild or asymptomatic infection; however, recent evidence links HCMV to breast cancer. In particular, the viral cytokine cmvIL-10 promotes proliferation, migration, and invasion of breast cancer cells in culture. Since HCMV is transmitted via human breast milk, we hypothesized that breast tumor cells could become infected and produce cmvIL-10. HCMV infection of breast cancer cells was confirmed with fluorescence microscopy. Viral gene expression was analyzed by PCR, and the supernatants contained virus particles that successfully infected fibroblasts. These results demonstrate that breast cancer cells support productive HCMV infection and may indicate that antiviral therapeutics could improve treatment outcomes for breast cancer patients.