to gain a better understanding of breast tumor angiogenesis , breast endothelial cells were isolated and evaluated for gene expression patterns . when transcripts from breast ecs derived from normal and malignant breast tissues were compared , genes that were specifically elevated in tumor - associated breast endothelium were revealed . these results confirm that neoplastic and normal endothelium in human breast are distinct at the molecular level , and have significant implications for the development of anti - angiogenic therapies in the future .