Machines Like Us

Within the next few months, researchers at three medical centers expect to start the first test in patients of one of the most promising -- and contentious -- ideas about the cause and treatment of cancer. The idea is to take aim at what some scientists say are cancerous stem cells -- aberrant cells that maintain and propagate malignant tumors.

Although many scientists have assumed that cancer cells are immortal -- that they divide and grow indefinitely -- most can only divide a certain number of times before dying. The stem-cell hypothesis says that cancers themselves may not die because they are fed by cancerous stem cells, a small and particularly dangerous kind of cell that can renew by dividing even as it spews out more cells that form the bulk of a tumor. Worse, stem cells may be impervious to most standard cancer therapies.

Read full story in The New York Times