OBJECTIVES: I. Determine the maximum target-inhibiting dose of SU5416 in patients with advanced solid tumors. II. Determine the relationship between dose or plasma levels and the clinical safety profile and antitumor effects of this treatment regimen in terms of objective response, stabilization of disease, or progression-free survival in this patient population. III. Evaluate the relationship between dose or plasma levels of SU5416 concentrations and the ability of this treatment regimen to reduce microvessel density and induce apoptosis of endothelial and tumor cells in this patient population. IV. Determine prognostic and surrogate serologic markers in these patients treated with this regimen. V. Determine if pre and posttreatment plasma and serum levels of angiogenic growth factors, basic fibroblast growth factor, and vascular endothelial cell growth factor are prognostic in predicting patient response to this regimen. VI. Determine if elevated plasma levels of endothelial cell specific proteins reflective of SU5416-induced endothelial damage and/or apoptosis are useful surrogate markers in assessing response to this treatment regimen in these patients.