Clinical aspects of AIDS-related Kaposi's sarcoma

Kaposi's sarcoma was one of the first conditions defining the new disease AIDS in 1981. From the outset, it was quite apparent that the biology of Kaposi's sarcoma in the setting of AIDS was quite different from that of most other known neoplasms. This observation led many investigators to speculate that Kaposi's sarcoma is, in fact, a reactive tumor and not a true malignancy. Our understanding of the pathogenesis of Kaposi's sarcoma has evolved over the years, and it now believed that the tumor arises from mesenchymal cells, which are influenced by HIV, various cytokines or growth factors, and perhaps other viruses or environmental factors operating in the setting of immune suppression. The tumor itself has various clinical manifestations, ranging from indolent cutaneous tumors to rapidly growing tumors involving lung and other viscera. New approaches to the treatment of Kaposi's sarcoma include inhibition of angiogenic and Kaposi's sarcoma stimulating growth factors, eg, interleukin-6, fibroblast growth factor, tumor necrosis factor, oncostatin-M, and the HIV-tat gene product. Additionally, improvement in our use of cytotoxic chemotherapy, interferons, and antiretroviral drugs has led to better management of complications of the tumor and of HIV itself. This review highlights recent advances in our understanding of Kaposi's sarcoma and its treatment, with a focus on pathogenesis and novel therapies.