Kaposi' s sarcoma in HIV-positive patients: The state of art in the HAART-era

Kaposi's sarcoma (KS) is a multicentric angioproliferative cancer of endothelial origin typically occurring in the context of immunodeficiency, i.e. coinfection with Human Immonodeficiency Virus (HIV) or transplantation. The incidence of KS has dramatically decreased in both US and Europe in the Highly Active Antiretroviral Therapy (HAART) era. However, KS remains the second most frequent tumor in HIV-infected patients worldwide and it has become the most common cancer in Sub-Saharan Africa. In 1994, Yuan Chang et al discovered a novel γ-herpesvirus in biopsy specimens of human KS. Epidemiologic studies showed that KS-associated herpesvirus (KSHV) or human herpesvirus- 8 (HHV-8) was the etiological agent associated with all subtypes of KS. KS has a variable clinical course ranging from very indolent forms to a rapidly progressive disease. HAART represents the first treatment step for slowly progressive disease. Chemotherapy (CT) plus HAART is indicated for visceral and/or rapidly progressive disease. The current understanding of KS as a convergence of immune evasion, oncogenesis, inflammation and angiogenesis has prompted investigators to develop target therapy, based on anti-angiogenic agents as well as metalloproteinase and cytokine signaling pathway inhibitors. These drugs may represent effective strategies for patients with AIDS-associated KS, which progress despite chemotherapy and/or HAART. In this review, we focus on the current state of knowledge on KSHV epidemiology, pathogenesis and therapeutic options.