University of Southern California researchers have confirmed for the first time cytomegalovirus (CMV), a common virus present in most people is a cause of salivary gland cancers and could possibly be responsible for other types of cancer malignancies.
The findings, published online in the journal Experimental and Molecular Pathology, are the latest in a series of studies by USC researchers that together demonstrate CMV's role as an oncovirus, a virus that can trigger cancer in healthy cells or exploit mutant cell weaknesses to enhance tumor formation.
With the finding, CMV joins a group of fewer than 10 cancer-causing viruses, including the human papillomavirus (HPV).
"This is just the tip of the iceberg with viruses,” said lead author Michael Melnick, a professor of developmental genetics in the USC Ostrow School of Dentistry and Co-Director of the Laboratory for Developmental Genetics in a written statement. “CMV may also be connected to other cancers besides salivary gland cancer.”
CMV's classification as a cancer-causing virus has important implications for human health. The virus has an extremely high prevalence in humans and can cause severe illness and death in patients with compromised immune systems and can cause birth defects if a woman is exposed to CMV for the first time during pregnancy.
The discovery came after rigorous study of both human salivary gland tumors and salivary glands of newborn mice. In the lab, cancer developed after newborn mice were exposed to purified CMV.
Efforts to stop the cancer progression identified how the virus sparked cancer within the cells. The researchers say this new information about CMV's connection to cancer brings hope for new prevention and more effective treatment methods.
CMV is one of the herpes viruses, a virus group that also causes chickenpox, shingles, Epstein-Barr and mononucleosis. CMV is a common infection that’s usually harmless in healthy children and adults with normal immune systems.
Once CMV is in a person's body, it stays there for life; there is no treatment currently available. The virus lies dormant within an infected person’s salivary glands.