Kaposi sarcoma-associated herpesvirus/human herpesvirus 8, cytokines, growth factors and HIV in pathogenesis of Kaposi's sarcoma.

Epidemiological studies have strengthened the case for Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 being the long-sought Kaposi sarcoma agent, but have also pointed to a role for other co-factors. Like other tumour viruses, Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 establishes a latent (persistent) infection in Kaposi sarcoma-spindle (tumorous) cells, but can also undergo lytic replication in these and other cell types. Several latent and lytic viral genes may play a role in the pathogenesis of Kaposi's sarcoma. Although Kaposi sarcoma-associated herpesvirus/human herpesvirus 8 contains at least two genes with transforming properties, it has not yet been shown to be oncogenic in animals. This, and other studies on inflammatory/angiogenic cellular and viral cytokines as well as HIV-Tat, emphasizes the multifactorial complexity of the pathogenesis of Kaposi's sarcoma.