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Viruses and Cancer

What Viruses Cause Cancer?

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Updated September 05, 2011

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

How many times have you been told by your doctor that you have a virus and the only treatment is to let it run its course? Probably quite a few times. We have all been infected with viruses in our lives -- the result being a sore throat, stomachache or other mild symptom. In many cases, viruses are quite harmless. In some cases, however, they can greatly compromise our health, causing many diseases and conditions, including cancer.

How Does a Virus Cause Cancer?

A virus is nothing more than DNA or RNA wrapped in a protein coat. What makes them unique is that they do not contain the necessary materials to function on their own. They are forced to invade a host cell (can be plant, animal, or bacterial) in order to thrive and reproduce. There are several ways that a virus can cause cancer. One way is for the virus that has invaded a host cell to alter the cell's genetic coding, causing a mutation. In turn, these actions can result in cancer. A Look At The Role of Viruses in Cancer

Viruses Known to Cause Cancer

Human Papillomavirus (HPV): The human papillomavirus (HPV) is sexually transmitted virus affecting over 20 million Americans. It is the most common type of sexually transmitted infection. There are currently over one hundred known strains of HPV. About thirty of these strains affect both male and female genitalia, causing conditions like genital warts and more seriously, cancer. HPV is linked to several types of cancer, including cervical, anal, vaginal, vulvar, and penile cancers. Recent research has shown that HPV is strongly linked to the development of certain types of throat cancers.
Hepatitis: Infection with Hepatitis B virus (HBV) or Hepatitis C (HCV) virus greatly put you at risk for developing liver cancer. These viral infections are extremely contagious are are spread through the transmission of blood, semen, and other bodily fluids from one person to another. Common means of exposure include unprotected sex, mother to infant transmission during childbirth, and the sharing of intravenous needles (most often by dug use, but can also occur during tattooing).

There is no vaccine for Hep C, but there is for Hep B. The hepatitis B vaccine is recommended for all children in the United States and is required for school entry. If you are an adult, take a look over your medical records to ensure you were properly immunized as a child. If you don't have access to those records, talk with your physician about how the vaccine may benefit you as an adult.

Epstein Barr Virus (EBV): The Epstein Barr virus is most commonly recognized for causing mononucleosis, but can also cause a few different types of lymphoma and nasopharyngeal cancer. It is important to note that not all people infected people with EBV will develop cancer. It is a very common virus that usually does not cause any major health problems.

EBV is transmitted through the saliva of an infected person. The virus is shed through a person's saliva during a period where the infected person does not have any symptoms. It can be spread through kissing, sharing a drink, or other means where a person may be exposed to another's saliva.

Human Immunodefiency Virus (HIV): AIDS related cancers are not directly caused by HIV or AIDS, but a combination of factors. It is believed that the weakened immune system caused by the virus makes people more vulnerable to developing cancer. Those with HIV/AIDS may also be at a higher risk for cancer because of factors such as smoking, drinking, and genetics.

Less Common Viruses Known to Cause Cancer

Viruses such as Human T-lymphotrophic virus-1 (HTLV-1) and Human herpes virus 8 (HHV-8) are related to cancer development, but are not as common as the viruses listed above. Several viruses are being investigated in their role in cancer development.

If you are concerned with your risk of cancer because of a viral infection, talk to your doctor. Together you can discuss your risk of cancer and if you need screening or more frequent screening for certain types of cancer.

Sources:

Daniels D, Grytdal S, Wasley A; Surveillance for acute viral hepatitis - United States, 2007.Centers for Disease Control and Prevention (CDC). http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5803a1.htm

Hildesheim, A, Schiffman, M, Bromley, C, et al. Human papillomavirus type 16 variants and risk of cervical cancer. J Natl Cancer Inst 2001; 93:315.

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