Viruses were once thought to be the sole cause of cancer. Although we now know that to be untrue, there are instances in which viruses can induce cancer formation. Instead of killing the host cell, some viruses are able to incorporate their nucleic acid into the sequence of the human genome. If the virus is able to force the human cell to grow uncontrollably, it can lead to tumor formation. Integration into the host genome is required for cancer formation to be induced. Often the body’s immune system is able to clear the virus before integration into the genome thereby preventing cancer formation.
Roughly 20% of all cancers worldwide are attributable to the presence of a virus. Well known viruses that induce cancer formation include human papillomavirus (HPV) which can cause cervical and throat cancer and hepatitis C virus (HCV) which can lead to liver carcinoma. Vaccinations are available to prevent numerous types of HPV. There are now also antiviral agents that can cure HCV infection. These medical advancements will lead to a reduction in the number of cancers due to HPV and HCV infection.
