With the pocket jammed, the protein can no longer function. In the case of GIST, Gleevec hits a receptor protein on the surface of the tumor cells known as c-kit. For reasons that are not fully understood, blocking c-kit leads to the destruction of the tumor cells. Because of the new understanding of tumors at the molecular level, some experts predicted that cancers would soon be classified by their molecular characteristics rather than the anatomical site of origin as is current practice. The excitement expressed in the scientific sessions and hallway conversations about Gleevec's benefits for two uncommon cancers transformed the somber mood of past meetings to one of ebullience this year.
Cancer cells are daunting to treat because they often have a number of genetic mutations.
They quickly develop resistance to the drugs that are thrown at them, suggesting that no one drug will ever be much use in itself. The unexpected success of Gleevec has raised oncologists' hopes that other drugs like Gleevec, alone or in combination, may bring down many different types of tumors. If the drugs do not cure the cancer, they may allow people to live with it as a chronic disease. We know that we can get very good responses and perhaps even cures with very specific targeted molecules. Imagine what we can do when we start combining them and hitting two or three targets at the same time.