Tumors have found a bloody new way to grow and spread

Mitch Leslie in Science:

TumorOn a cool day in March 2000, several hundred researchers jammed into a hotel auditorium in Salt Lake City, eager to see a showdown over what had become one of the most controversial ideas in cancer research. On one side stood cancer biologist Mary Hendrix of the University of Iowa Cancer Center in Iowa City, whose team the year before had reported an unusual, seemingly new way through which tumor cells can tap into the blood supply and obtain nutrients. Facing off against her was tumor vascular biologist Donald McDonald of the University of California, San Francisco, who was certain that she and her colleagues had misinterpreted their data. “This debate had the feeling of a boxing match—with the championship belt hanging in the balance,” Hendrix recalls.

Researchers knew at the time that tumors can induce the endothelial cells of normal blood vessels to form new supply lines into a tumor, a process called angiogenesis. But Hendrix and her colleagues contended that tumor cells themselves sometimes create their own blood-delivering tubes, a mechanism they dubbed vasculogenic mimicry (also known as vascular mimicry). Their 1999 paper “started lots of upheaval,” says histopathologist Francesco Pezzella of the University of Oxford in the United Kingdom. The Utah debate, held at a Keystone meeting, was the first public discussion of the concept. In the end, neither side scored a knockout. Hendrix asserted that the loops and networks her team had observed represented a mini–circulatory system produced by the tumors themselves. McDonald countered that the patterns were folds of connective tissue, not tubes that carried blood. In the years since, the controversy has waned, and Hendrix and other researchers have pieced together a picture of how tumors build their own blood vessels and how they can affect prognosis and treatment. But some scientists continue to find the idea deeply unsettling. Now, vasculogenic mimicry faces another big test. The first clinical trial of a drug to block the process—and thus potentially limit tumor growth—has begun in the United States and Taiwan. If the drug succeeds, it would bolster what Hendrix and other researchers have been saying about these do-it-yourself blood vessels for nearly 17 years. And it might also explain why some of the most hyped drugs in cancer therapy—angiogenesis inhibitors—have underperformed.

More here.