These viruses have been linked to cancer

Though it's difficult to determine a specific cause of cancer, the American Cancer Society notes that some forms of cancer are found more often in people who have been infected with certain viruses. Infection with the following viruses does not necessarily mean a person has cancer, but there does seem to be a connection between these viruses and cancer.

* Human papillomavirus: The Centers for Disease Control and Prevention note that human papillomavirus, or HPV, is the most common sexually transmitted virus in the United States. There are more than 40 types of HPV, and they can affect both men and women, though many people who have HPV do not know they have it. HPV has been linked to many different types of cancer, most notably cervical cancer. HPV has also been linked to cancers of the vagina, vulva, penis, and anus, and new research has suggested that HPV may be linked to cancers of the mouth, throat, head, and neck.

* Epstein-Barr virus: Often referred to as EBV, Epstein-Barr virus is a type of herpes virus and is one of the most common human viruses across the globe. EBV infection does not typically occur during childhood in developed countries, but children are not immune to the virus. Research has shown a link between EBV and nose and throat cancer, lymphoma of the stomach, Hodgkin's lymphoma, and Burkitt's lymphoma.

* Hepatitis B virus and Hepatitis C virus: The Hepatitis B virus, known as HBV, causes Hepatitis B, an infectious and inflammatory illness of the liver. The Hepatitis C virus, or HPC, causes Hepatitis C, an infectious disease that can cause scarring of the liver and potentially cirrhosis. Both viruses have been linked to long-term liver infections, which can increase a person's risk of developing liver cancer.

* Human herpes virus type 8: Human herpes virus type 8, commonly referred to as HHV-8, is also known as Kaposi's sarcoma herpes virus. How the virus is contracted is not well understood, and infected individuals who are otherwise healthy may show no signs or symptoms of the virus. A healthy immune system can keep the virus in check, but those with suppressed immune systems are at high risk of infection. HHV-8 is linked with a type of cancer called Kaposi's sarcoma, though the majority of people with HHV-8 do not develop Kaposi's sarcoma unless they are also HIV-positive. When coupled with HHV-8 medications that weaken the immune system, such as those that may be prescribed after an organ transplant, may increase a person's risk of getting Kaposi's sarcoma.