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Viruses and Cancer

Peer Review Status: Internally Reviewed
First Published: October 2001
Last Revised: May 2003

Around 100 years ago researchers considered the possibility that cancer could be caused by viruses or other infectious organisms. Their attempts to prove this theory failed. However, in the past twenty years, scientists have demonstrated that viruses do cause some cancers. In the United States today about 5% of cancer deaths are attributed to viruses.

A virus cannot be said to be dead or alive. A virus has to depend on another living cell (host cell) to reproduce. When a virus comes in contact with a host cell, a virus can insert its genetic material into its host, literally taking over the host's functions. An infected cell produces more viral protein and genetic material instead of its usual products. As a result of the viral infestation, the host cells die.

There are several viruses that are linked to cancerous tumors:

How do you prevent being infected with these viruses? The answer is not simple because viruses as a cause of cancer are a newly discovered phenomenon. Because the Human Papilloma and Hepatitis viruses are sexually transmitted, one way to protect yourself is to practice safe sex. Judicious hand washing and avoiding touching the mouth and nose area of the face are healthy habits that everyone needs to practice. As scientists learn more about viruses and cancer, more prevention tips likely will evolve.