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. No one knows why it reactivates in some people.
The virus is widespread within the global society. Among every 100 adults in the United States, 50–80 are infected with CMV by the time they are 40 years old, the Centers for Disease Control and Prevention (CDC) reports.
“Salivary gland cancers can be particularly problematic because they often go undiagnosed until they reach a late stage. And since the affected area is near the face, surgical treatment can be quite extensive and seriously detrimental to a patient's quality of life,” said Tina Jaskoll, professor of developmental genetics and co-director of the Laboratory for Developmental Genetics, who was associated with the finding.
Early stage salivary gland cancer may not cause any symptoms. The cancer may be found during a routine dental examination or health exams.
Symptoms, when present, including a lump (usually painless) in the area of the ear, cheek, jaw, lip, or inside the mouth; fluid draining from the ear; trouble swallowing or opening the mouth widely; numbness or weakness in the face, or facial pain that does not go away, should be examined immediately by a doctor, according to the National Cancer Institute, part of the National Institutes of Health.
CMV is spread by close contact with a person who has the virus in his or her saliva, urine, or other body fluids. CMV can be transmitted sexually, and from a pregnant woman to her fetus during pregnancy.
About one-third of women who become infected with CVM for the first time during pregnancy pass the virus to their unborn babies. Most babies born with CVM appear healthy at birth. About 20 percent develop long-term health problems or physical disabilities after age two.
Melnick says in the not too distant future, he expects much more information about viruses and their connections to cancer and other health issues seemingly unrelated to viral infection to emerge.
“This should be a most fruitful area of investigation for a long time to come," he said.
Lynette Summerill, an award-winning writer and scuba enthusiast lives in San Diego, CA with her husband and two canine kids. In addition to writing about cancer-related issues for EmpowHER, her work has been seen in newspapers and magazines around the world.
Sources:
Researchers confirm new cancer causing virus. University of Southern California news release via Eurekalert. 14 Nov. 2011
http://www.eurekalert.org/pub_releases/2011-11/uosc-rcn111411.php
Cytomegalovirus (CMV) and Congenital CMV Infection. Centers for Disease Control and Prevention. Accessed online 16 Nov. 2011 at: http://www.cdc.gov/cmv/overview.html
Salivary Gland Cancer. National Cancer Institute. Accessed online 16 Nov. 2011 at: http://www.cancer.gov/cancertopics/pdq/treatment/salivarygland/Patient
Reviewed November 17, 2011
by Michele Blacksberg RN
Edited by Jody Smith