Alpha(v)-beta(3) integrins are thought to promote survival of endothelial cells and the formation of tumor blood vessels in vivo, and the role of the integrins in tumor angiogenesis has been supported by overexpression of the integrin on tumor endothelial cells, while inhibition of beta(3) integrin signaling has been shown to decrease blood vessel formation in certain in vivo models.

The theory thus has been that inhibiting the integrin will block angiogenesis and starve the tumor of oxygen. Last week, however, researchers published evidence that antagonizing the integrin could have tumor-promoting activity in some circumstances.