7 viruses that cause cancer

Researchers know that there are several viruses that can lead to cancer. For example, the human papillomavirus (HPV) can cause cervical and several other cancers. And hepatitis C can lead to liver cancer and non-Hodgkin’s lymphoma.

Studying viruses and cancer is helping researchers develop vaccines and other ways to reduce cancer risk. We spoke with Harrys Torres, M.D., associate professor of Infectious Diseases, to learn more. Here’s what he had to say.

How do viruses cause cancer?

Viruses are very small organisms. They are made up of genes – DNA or RNA – surrounded by a protein coating. There are several oncoviruses, or viruses that causes cancer:

Epstein-Barr virus (EBV) is a herpes virus that’s spread through saliva. EBV infection increases the risk of Burkitt lymphoma, some types of Hodgkin’s and non-Hodgkin’s lymphoma and stomach cancer. There is currently no vaccine for Epstein-Barr virus.

Hepatitis B virus (HBV) is spread through infected blood, semen and other body fluids. Hepatitis B is a leading cause of liver cancer. The hepatitis B vaccine is recommended for all children and adults. If you are not sure if you’ve been vaccinated, talk to your doctor.

Hepatitis C virus (HCV) is spread through infected blood. Hepatitis C is a leading cause of liver cancer, and can cause non-Hodgkin’s lymphoma. There is no vaccine against hepatitis C, but it is highly treatable.

Human immunodeficiency virus (HIV) is spread through infected semen, vaginal fluids, blood and breast milk. While it does not cause cancer directly, researchers believe it increases the risk of cancer by damaging the immune system, which reduces the body’s defenses against other oncoviruses. It can enable other oncoviruses to cause cancer. HIV-associated cancers include Kaposi sarcoma, non-Hodgkin’s and Hodgkin’s lymphoma, cervical cancer, and cancers of the anus, liver, mouth and throat and lung. There is no vaccine against HIV.

Human herpes virus 8 (HHV-8) is related to Kaposi sarcoma in people who have a weakened immune system. That includes patients with HIV.

Human papillomavirus (HPV) has at least 12 strains that can cause cancer in men and women, including anal, cervical, penile, throat, vaginal and vulvar cancer. Boys and girls age 11-12 should get the HPV vaccine. It’s available for patient from age 9-26.

Human T-cell leukemia virus type, also called human T-lymphotrophic virus (HTLV-1) is linked to adult T-cell leukemia/lymphoma. It is spread through infected semen, vaginal fluids, blood and breast milk. The infection is rarely found in the United States.

The effects of these viruses on cancer development is highly complicated. Experts don’t fully understand how most known oncoviruses cause cancer. What is known is that viruses highjack cells and insert their own DNA or RNA into the host cell. This can cause the host cells to become cancerous.

What can people do to avoid getting these cancer-causing viruses?

You can take steps to reduce your risk of getting oncoviruses.

• Get vaccinated. The HPV vaccine can help reduce risk of HPV-related cancer. The hepatitis B vaccine can help reduce your liver cancer risk.
• Get screened. Screening is available for some cancer-related viruses, like HPV, HIV and hepatitis B and C. If you’re at risk, get screened. In addition, follow our cancer screening guidelines. Screening is one of the best ways to catch cancer early, when it’s easiest to treat. Talk to your doctor to learn if you need earlier or additional screening.
• Practice safe sex. Viruses like HPV, HIV, hepatitis B and C are sexually transmitted.
• Don’t use illegal drugs, share syringes, needles or other infected equipment or personal items that might have blood on them.

If you think you may have or be at risk for an oncovirus, talk to your doctor about reducing your cancer risk.