What is Reovirus?

The Reovirus is a naturally occuring virus that is believed to cause mild infections of the upper respiratory and gastrointestinal tract of humans.

Viruses normally cause disease. Why is this one significant in cancer research?

Dr. Patrick Lee found that the reovirus is a potent killer of cancer cells whose growth signal has gone away. He discovered that the reovirus selectively kills cells with an activated Ras pathway. Infection of a single cancer cell by a single reovirus particle can generate a thousand progeny reovirus particles,which in turn infect neighbouring cancer cells. This cycle continues until all cancer cells are eliminated. Normal cells are spared.

Normally, cells are naturally protected against reovirus. But a reovirus kills cancer cells because an oncogene known as the Ras gene makes a protein that destroys that protection.