The Facts

Kaposi's sarcoma is a cancer found in the tissues under the skin or in the mucous membranes, the lining of the mouth, nose, and anus. It can also affect the internal organs. It's the most common cancer found in people with acquired immunodeficiency syndrome (AIDS), and occurs as a complication of AIDS. Men infected with the human immunodeficiency virus (HIV) are affected about eight times more often than women with HIV. It is also more common among people taking immunosuppressive medications (for example, organ transplant recipients).

Before AIDS became widespread, Kaposi's sarcoma was usually only found in senior men, usually of Italian, Jewish, or African descent. It was also found in people who had received organ transplants and were taking immunotherapy to avoid organ rejection. In people with AIDS, the tumor grows and spreads more quickly than in senior men.

Causes

Researchers don't know what causes Kaposi's sarcoma. There is a known increase in the condition among people who have a depressed immune system, such as those with AIDS, or those taking immunosuppressant therapy after receiving an organ transplant. The most likely cause of this condition is the combination of immune depression, as occurs with HIV infection, and exposure to the human herpesvirus 8 (HHV 8), a sexually transmitted infection. While the condition is most prevalent among sexually active homosexual and bisexual males with HIV, the improvement in the medical treatment of HIV appears to have reduced the incidence of this condition. The incidence of the condition in heterosexual people with HIV is far lower.