 Topotecan at the dose of 1.2 mgm2 will be administered orally daily x 5 for 2 weeks, during a 28 days cycle. Imaging studies including CT and DCE-MRI will be performed at baseline, at the end of treatment on cycle 1 day 9 or 10, end of treatment on cycle 2 day 12 or 13 and will provide information on clinical response as well as tumor angiogenesis. The repeat scans on day 9 or 10 of cycle 1 will be performed solely for research purposes to evaluate for early changes in tumor angiogenesis. Additional correlative studies include evaluation of mRNA expression of HIF-1 target genes in tumor tissue, circulating markers of angiogenesis, and measurement of circulating endothelial precursor cells CEP. The goal of this trial is to establish whether topotecan inhibits HIF-1alpha and angiogenesis in human cancers. 