evidence: Kaposi sarcoma is always caused by an infection with a virus called human herpesvirus 8, which is also known as Kaposi sarcoma-associated herpesvirus (KSHV). The virus, which is in the same family as Epstein-Barr virus, is rare in the United States. In fact, less than 1 percent of the general U.S. population is a carrier. The virus and the tumor are much more common in some other parts of the world. [...] In the United States, most cases of Kaposi sarcoma are related to HIV. HIV only leads to the development of Kaposi sarcoma in patients who are also KSHV infected. [...] KSHV, the virus that causes Kaposi, cannot be treated. Once you contract KSHV, you will always have it. Treatment for Kaposi sarcoma is focused on managing symptoms and treating the cancer. The best approach will depend on your specific diagnosis and the extent of the disease.