How Cancer Spreads: Cells 'Chase and Run' Study may lead to treatment that can halt cancer's spread By Evann Gastaldo, Newser Staff Posted Jun 17, 2013 1:25 PM CDT 7 comments Comments Stock image of cancer cells. (Shutterstock) (Newser) – Scientists have figured out how cancer metastasizes, and they think the findings could help develop drugs to halt the disease's spread, the Telegraph reports. The study, published in Nature Cell Biology, describes a phenomenon researchers call "chase and run," in which cancer cells and healthy cells follow each other through the body. Though healthy cells try to escape, the Milwaukee Journal Sentinel explains, they produce small molecules, which in turn attract malignant cells to the healthy cells. "We use the analogy of the donkey and the carrot to explain this behavior: The donkey follows the carrot, but the carrot moves away when approached by the donkey," the lead author says. "Nobody knew how this happened, and now we believe we have uncovered it. If that is the case it will be relatively easy to develop drugs that interfere with this interaction." Researchers came to their conclusions by using comparable cells to mimic the behavior of cancer cells and healthy cells. The lead author notes that most cancer deaths are actually the result of a secondary tumor, not the original.