Can Cancer Be Viral?
You might not know it, and you may have been told by your doctor it's harmless, but most of us are infected with a herpes virus called Epstein-Barr virus (EBV). For most, not all, the virus reveals itself as glandular fever or infectious mononucleosis. Now, in a quest to understand "How do viruses cause cancer in humans?" more and more research is associating EBV with cancer.
EBV Associated With Cancer
Alarmingly, a German study published in the Cell Press journal Cell Reportsshed light on how viruses cause cancer in humans and found that the difference between a seemingly harmless virus and a cancer-causing one lies partly in the viral strain itself.
The results offer some of the first evidence for the existence of distinct EBV subtypes with very different public health risks. The plan according to researchers is to create vaccines and strategies to prevent EBV infection with the cancer-causing strains of the virus in mind.
EBV Has Different Strains
"EBV is an important but neglected pathogen," said Henri-Jacques Delecluse of the German Cancer Research Centre in Heidelberg, Germany. "We have made an important step in recognizing that EBV is actually a family of viruses that have different properties, some of which are very likely to cause disease. So, the consequences of being infected with EBV might be different, depending on the strain one carries."
Cancer-Causing Strain of EBV Isolated
Delecluse and his colleagues made the discovery by sequencing the DNA of a viral strain that they called M81 isolated from a Chinese patient with nasopharyngeal carcinoma. Their analyses revealed that M81 is highly similar to other viruses isolated from nasopharyngeal carcinoma and profoundly different from Western strains in terms of its ability to infect and replicate within cells.
How Do Viruses Cause Cancers In Humans?
The M81 strain can infect epithelial cells and multiply spontaneously at a very high level in all cells it infects, including B lymphocytes, the cells in which the viruses hide, the researchers report. It remains to be seen exactly how infected epithelial cells become cancerous.
New Strategy For Dealing With EBV
"Our results have made me radically change my strategy to address the problem of EBV-associated diseases," Delecluse said. "The current view is that the virus is essentially the same all over the world and that local conditions explain the different consequences of EBV infection. We now show that the type of EBV also plays an important role. By concentrating on the potentially pathogenic EBV strains, we will soon better understand how EBV causes diseases, and this will also help [in] designing prevention strategies."
— Hanan Polansky (@HananPolansky) November 30, 2015
— Contagion (@Contagion_Live) November 17, 2016