In a paper published online in advance in the PNAS Early Edition this week, a team led by investigators at Harvard Medical School shows that, in a mouse model of pancreatic neuorendocrine cancer, administration of the endogenous angiogenesis inhibitors endostatin, thrombospondin-1, and tumstatin peptides, "as well as deletion of their genes, reveal neoplastic stage-specific effects on angiogenesis, tumor progression, and survival, correlating with endothelial expression of their receptors." Further, the team reports its finding that the deletion of tumstatin and thrombospondin-1 in