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The numerous different types of cancer that can affect the human body have a multitude of known and unknown causes. One known phenomenon that can increase the risk of developing certain types of cancer is the presence of a virus in the body that alters the way in which cells grow and divide. Cancer viruses are types of viral infections that are known to alter the makeup of cells, so that they are more likely to behave erratically, resulting in tumor formation. There are two distinct types of cancer viruses, known as DNA viruses and RNA viruses.
Most viruses that affect humans are not capable of causing cancer, and those that can will not do so in every person. Since cancer is the result of a combination of many factors, both genetic and environmental, viruses alone cannot be singled out as the primary cause for any disease. For a virus to cause tumor growth, it must enter a cell and alter its genetic material. This alters the way in which the cell operates, making it immune to anti-growth signals from the brain and to the cell aging process that prevents excessive division. The way in which a virus impacts a cell depends on whether it is a DNA or RNA virus.
DNA viruses place their genetic information directly into the nucleus of the body's cells. Such viruses include the human papilloma virus (HPV), herpes, the Epstein-Barr virus and hepatitis B. HPV, a sexually transmitted infection, is known to be a potential cause of cervical cancer in women and is also associated with other cancers of the genital areas and the throat. Herpes is related to the development of a form of sarcoma known as Kaposi, in which abnormal tissue growth occurs underneath the skin.
More commonly known as mono, the Epstein-Barr virus is a very common infection related to herpes. It is transmitted through close human contact, such as kissing, and infects the body's B cells. While a high percentage of adults contract this virus at some time and experience very few side effects, a small number can go on to develop cancers known as Burkitt's lymphoma or nasopharyngeal carcinoma. Hepatitis B is one of the cancer viruses that targets a specific organ. It can result in liver cancer in patients experiencing repeated liver infections from the virus.
For RNA cancer viruses to infect their hosts, they must first change their RNA into DNA, then insert their genetic material into the cell. Hepatitis C is a type of RNA virus that acts much like hepatitis B, resulting in liver cancer. Another type, human T lymphotrophic virus type 1 (HTLV-1), attacks the lymphatic system and is associated with T-cell leukemia.
As of 2012, research into cancer viruses remains in its infancy, and treatments to target viral infections before they can cause cancer are still being developed. Some vaccines have been created to attempt to prevent viruses, such as HPV and hepatitis B, but no vaccine can provide complete protection. Early diagnosis and treatment are still the keys to increasing survival rates of all types of cancer.
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