It is estimated that one in ten cancers is caused by viruses. The most common viral causes of cancer are human papillomavirus, Epstein-Barr virus and hepatitis virus. For example, human papillomavirus can cause cervical cancer and throat tumors. Epstein-Barr virus, which is a herpes virus, is associated with various types of lymphoma. And the hepatitis B and C viruses can lead to liver cancer.
In order to replicate, some viruses have to introduce their genetic material into the host cell's genome. This can lead to the switching on or off of genes with important control functions that regulate the growth or survival of the host cell. If such cells continue to grow uncontrollably, cancer can develop.
Vaccines offer the best protection against viral infection. Vaccines against the hepatitis B virus and individual human papillomaviruses are currently available to prevent cancer. These protect against cervical cancer and liver cancer - but only if administered before exposure to the cancer-promoting virus. Scientists around the world are conducting intensive research into further vaccines. The Swiss Cancer Research foundation helps them in this endeavor and has regularly supported high-quality projects in this field for many years.