Although most people are infected with the Epstein-Barr virus, the pathogen rarely causes cancer. Now, scientists say, they have uncovered how our cells prevent this virus from bringing on cancerous growth.
The study is one of the first to examine what happens inside cells immediately after they are infected with Epstein-Barr.
The findings could help researchers better understand how people respond to cancer-causing viruses in general, the researchers said.
The results might also help researchers find ways to prevent cancers, such as lymphoma, that can be induced by Epstein-Barr virus. People whose immune systems have been compromised, such as those with an HIV infection, are particularly at risk for developing these cancers.
However, the new study is based on cells grown in lab dishes, and further research is needed to determine if the results hold true inside the human body.
The study “gives us a handle on how…a virus is testing the cell's response in order to achieve its goal,” which is to copy its DNA and get passed around, said study researcher Micah Luftig, an assistant professor of molecular genetics and microbiology at Duke University in Durham, N.C. The findings “give us molecular probes, if you will, to be able to study how this might actually be going on in cancer,” he said.
About 95 percent of adults worldwide have been infected with the Epstein-Barr virus. Most people catch the bug when they are very young, and there are often no symptoms. However, if a person is immunocompromised, they are 20 to 100 times more likely to develop cancer from the virus, Luftig said.
Luftig and his colleagues pinned down the pathway by which healthy cells ward off cancer after they've been infected by Epstein-Barr.
The researchers saw that, immediately after infection, the virus forced immune cells called B cells into a state of hyper-proliferation, in which the cells excessively grow and multiply.
During such rapid division, the DNA within cells can become damaged. But, the researchers found, special sensors within cells recognize damaged DNA and trigger the cell to kill itself.
“Very early on after infection, most of the cells that would be potentially transformed — turned into tumor cells — are killed because the cell responds to the way the virus is telling it to divide,” Luftig said.
When the researchers blocked two of these sensors, many more infected cells turned cancerous than did when the sensors were working.
While these particular sensors, known as kinases, had been identified before, this was the first time researchers had seen them at work in cells infected with Epstein-Barr, Luftig told MyHealthNewsDaily.
It's possible that simply reactivating this pathway may protect vulnerable people from developing cancer due to Epstein-Barr infection.
A similar pathway could be at work in a number of different cancer-causing viruses, Luftig said.
The results were published today (Dec. 15) in the journal Cell Host and Microbe.
Pass it on: Healthy cells have sensors that prevent Epstein-Barr infections from turning into cancer.