The acquired immunodeficiency syndrome (AIDS) and the AIDS- related complex (ARC) are caused by the human immunodeficien- cy virus (HIV-I), previously known as human T-celllymphotropic virus type III (HTLV-III) or lymphadenopathy-associated virus (LA V). It seems that additional retroviruses (HIV-II and perhaps 1 3 others) are able to cause variants of AIDS or ARC. - Patients infected wi~h the virus may (but do not necessarily) de- velop a wide range of clinical symptoms that are not directly relat- ed to the virus itself, but are secondary to the devastating effects of the viral infection on’ the human immune system. The virus thus renders the patient susceptible to a variety of opportunistic infec- tions with other viruses (such as cytomegalovirus), bacteria, fungi, and protozoa, as well as to the development of simultaneous or subsequent malignant tumors. The new topic of AIDS and cancer is a challenging and frighten- ing aspect of present-day medicine and health politics. With the growing prevalence of the human immunodeficiency virus(es) and clinical correlates ranging from persistent generalized lymphaden- opathy (PGL) to full-blown AIDS in our population, we will also encounter a steadily rising number of patients with both AIDS and neoplasias, such as Kaposi’s sarcoma, Hodgkin’s and non-Hodg- kin’s lymphomas, anal cancer, and a variety of additional malig- 4 nant tumors. , 5 1 Gallo RC, Salahuddin SZ, Popvic M et a!. (1984) Frequent detection and isolation of cytopathic retroviruses (HTL V-III) from patients with AIDS and at risk for AIDS. Science 224: 500-503.