In 1872, Moritz Kaposi described a blood vessel tumor (originally called "idiopathic multiple pigmented sarcoma of the skin") that has since been eponymously named Kaposi's sarcoma (KS). KS was at first thought to be an uncommon tumor of Jewish and Mediterranean populations until it was later determined to be extremely common throughout sub-Saharan African populations. This led to the first suggestions in the 1950s that this tumor might be caused by a virus. With the onset of the AIDS epidemic in the early 1980s, there was a sudden resurgence of KS affecting primarily gay and bisexual AIDS patients, with up to 50% of reported AIDS patients having this tumor—an extraordinary rate of cancer predisposition.