Patients undergo a biopsy during prestudy and after the second course of treatment. Patients receive endostatin IV daily for 4 weeks. Patients on dose level 1-6 receive endostatin over 20 minutes. Patients on dose level 7 receive endostatin over 40 minutes, with no treatment on day 2 of the first course only. Treatment continues every 4 weeks in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients receive escalating doses of endostatin until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose limiting toxicity.