Robert Langreth, 12.27.04
Radical researchers are onto a controversial idea for stopping cancer:go after stem cells
Peter Dirks uses a talented pair of hands to cut cancer out of the brains of sick children. But no matter how brilliantly he performs, he rarely is able to stop cancer's return; sometimes the tumors come roaring back just months after he excises all visible signs of disease.
This inevitability--of children dying in the face of his best attempts to heal them--got to him. "It broke my heart that we couldn't do more for them," says Dirks, a surgeon-scientist at the University of Toronto-affiliated Hospital for Sick Children. So in desperation he set out six years ago to pursue a radical new theory of what truly fuels cancer's growth, one that might unlock new therapies and explain why today's treatments often provide only fleeting help.
His concept was so fringy that government agencies repeatedly rejected his grant proposals. Parents of several of his patients kept the research going by donating $100,000 to his efforts; one of the couples even took up a collection at their child's funeral. But this fall Dirks reported a breakthrough that could dramatically alter our understanding of how cancer grows. His revelation, which could take a decade or more to take hold, is the latest in a string of findings that may one day uncloak the key triggers of many different kinds of cancer.
Scientists have long assumed that all of the dozens of kinds of cells inside a tumor are created equal--and are equally deadly, capable of spreading elsewhere in the body to create a totally new tumor. So they focus on chemotherapy that kills as many cancer cells as possible.
Dirks and a handful of other mavericks argue that this indiscriminate approach is wrongheaded. They believe a single type of cell may be cancer's main growth engine:mutant stem cells that, though barely present, spawn other cells that then spark growth. "This has profound implications," says researcher Thomas Look of Boston's Dana-Farber Cancer Institute. "The major cells you see under a microscope may not be the ones you need to kill in order to cure the disease." He adds that the theory "is definitely still very controversial" in some quarters.