To
gain a better understanding of
tumor angiogenesis, new techniques for isolating endothelial cells (ECs) and evaluating
gene expression patterns were developed. When transcripts from ECs derived from normal and malignant colorectal tissues were compared with transcripts from non-endothelial cells, over 170 genes predominantly expressed in the
endothelium were identified. Comparison between normal- and tumor-derived
endothelium revealed 79
differentially expressed genes, including 46 that were specifically elevated in tumor-associated
endothelium. Experiments with representative genes from this group demonstrated that most were similarly expressed in the endothelium of primary
lung, breast, brain, and pancreatic cancers as well as in metastatic lesions of the liver. These results demonstrate that neoplastic and normal endothelium in humans are distinct at the
molecular level, and have significant implications for the development of anti-angiogenic therapies in the future.