 To assess the antitumor effect of bevacizumab 15 mgkg administered intravenously once every three weeks in patients with human immunodeficiency virus HIV-associated Kaposis sarcoma KS. Other objectives include assessment of the antitumor effect of bevacizumab 15 mgkg administered intravenously once every three weeks in patients with classical KS; assessment of the toxicity profile of bevacizumab in HIV-infected and HIV-negative patients with KS; exploration in a preliminary fashion effect of bevacizumab on KS progression free survival; and study of a number of biochemical parameters, including stromal cell-derived factor-1 SDF-1 expression in KS lesions; human herpes virus-8 HHV-8 viral load in peripheral blood mononuclear cells; serum vascular endothelial growth factor VEGF levels over the course of treatment; and changes in viral interleukin 6 IL-6 levels over the course of treatment. 