Up to 15% of all cancer cases are thought to be caused by viruses. A virus operates with a completely different mechanism than chemical carcinogens. Viruses are spread from person to person by coughing, sneezing, ingestion and sexual contact. Once a virus enters the individual’s body it may take action or it may lay dormant until it is signaled to act.

Once signaled, the virus attaches itself to a cell and injects its DNA into it. The viral DNA will become incorporated into the DNA strand of the host cell so that when the cell makes its proteins, it will also make the virus. This is the only way a virus can replicate, without a host cell it will just lay dormant. Eventually, the cell will become so full of the new virus it will burst open, releasing all of its contents, including the viruses. These new viruses will be able to inject their DNA into a healthy cell and the process will repeat itself.